1 
 

 TABLE OF CONTENTS 
 
 Section Page 
 
 Introduction, 5 
 
 I. General Railway Signal Electric Inter- 
 locking System, 13 
 
 II. General Railway Signal Electric Inter- 
 locking Appliances, 29 
 
 III. General Railway Signal Alternating 
 
 Current Appliances, 107 
 
 IV. Signal Lighting at Interlocking Plants, 125 
 V. Electric Locking and Check Locking, . 131 
 
 VI. Installation and Operating Data for 
 
 Power Plants and Switchboards, . . 143 
 VII. Installation and Operating Data for 
 
 Electric Interlocking Machines, . . 183 
 VIII. Installation and Operating Data for 
 
 Switch Mechanisms, 197 
 
 IX. Installation and Operating Data for 
 
 Signal Mechanisms, 235 
 
 X. Installation and Operating Data for 
 
 Relays and Indicators, 263 
 
 XL Installation and Operating Data for 
 
 Transformers, 277 
 
 XII. Installation and Operating Data for 
 
 Primary Batteries, 283 
 
 XIII. Wire, Trunking, and Conduit, ... 295 
 
 XIV. Portland Cement Concrete, .... 319 
 XV. Written Circuits, 329 
 
 XVI. Signal Aspects and Symbols, .... 341 
 
 XVII. General Data, 361 
 
 XVIII. Appendix, . 403 
 
 Index, .419 
 
ELECTRIC 
 INTERLOCKING 
 HANDBOOK | 
 
 BY THE 
 
 ENGINEERING STAFF OF THE 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 WITH AN INTRODUCTION BY 
 
 WILMER W. SALMON 
 
 HENRY M. SPERRY, EDITOR 
 M. Am. Soc. C. E. 
 
 PAUL E. CARTER, ASSISTANT EDITOR 
 SHERMAN A. BENEDICT, ILLUSTRATOR 
 
 PRICE $3.00 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 ROCHESTER, N. Y. 
 1913 
 

 COPYRIGHT, 1913, BY 
 
 GENERAL, RAILWAY SIGNAL. CO. 
 
 ROCHESTER, N. Y. 
 
THE ENGINEERING STAFF 
 
 OF THE 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 WINTHROP K. HOWE, CHIEF ENGINEER 
 
 M. A. I. E. E. 
 
 FRANK L. DODGSON, CONSULTING ENGINEER 
 WILLIAM S. HENRY, PRINCIPAL ASSISTANT ENGINEER 
 
 JAMES B. EVANS, ASSISTANT ENGINEER 
 
 SEDGWICK N. WIGHT, COMMERCIAL ENGINEER 
 
 SALISBURY M. DAY, ELECTRICAL ENGINEER 
 
 264319 
 
GENERAL RAILWAY SIGNAL COMPANY 
 
 WILMER W. SALMON, 
 PRESIDENT AND GENERAL, MANAGER 
 
 GEORGE D. MORGAN, CLARENCE H. LITTELL, 
 
 VICE-PRESIDENT SECRETARY 
 
 PRINCIPAL OFFICE AND WORKS 
 ROCHESTER, N. Y. 
 
 BRANCH OFFICES: 
 
 NEW YORK OFFICE 
 
 LIBERTY TOWER BUILDING, 55 LIBERTY STREET 
 NEW YORK, N. Y. 
 
 CHICAGO OFFICE 
 
 PEOPLE'S GAS BUILDING, 122 SOUTH MICHIGAN AVENUE 
 CHICAGO, ILL. 
 
 SAN FRANCISCO OFFICE 
 
 MONADNOCK BUILDING, 681 MARKET STREET 
 
 SAN FRANCISCO, CAL. 
 
 CANADIAN AGENCIES 
 
 GENERAL RAILWAY SIGNAL COMPANY OF CANADA, LTD. 
 LACHINE, P. Q. 
 WINNIPEG, P. M. 
 
 AUSTRALASIAN AGENCIES 
 R. W. CAMERON & Co. 
 
 SYDNEY 16 SPRING STREET 
 
 MELBOURNE, 34 QUEEN STREET 
 
 BRISBANE NEW ZEALAND CHAMBERS 
 
 PERTH, . . SELBORNE CHAMBERS 
 
 WELLINGTON, N. Z., AUSTRALASIA CHAMBERS 
 
GENERAL RAILWAY SIGNAL COMPANY 
 
 ENGINEERS, MANUFACTURERS, AND ERECTORS OF 
 
 RAILWAY SIGNAL APPLIANCES 
 
 PRODUCTS 
 
 ELECTRIC INTERLOCKING 
 
 MECHANICAL INTERLOCKING 
 
 AUTOMATIC BLOCK SIGNALS, DIRECT CURRENT 
 
 AUTOMATIC BLOCK SIGNALS, ALTERNATING CURRENT 
 
 MANUALLY OPERATED BLOCK SIGNALS 
 
 TELEPHONE SELECTORS 
 
INTRODUCTION 
 
 INTERLOCKING is of English origin, numerous patents 
 having been granted in England for manually operated 
 interlocking devices from 1856 to 1867, at which later 
 date was first disclosed by Saxby a satisfactory means for 
 obtaining what is now known as "preliminary latch locking." 
 The rapidity with which this valuable system was adopted in 
 England is indicated by the fact that six years later, in 1873, 
 13,000 mechanical interlocking levers were employed on the 
 London & Northwestern Railway alone, at which time not a 
 single lever was in use in the United States, the first experi- 
 mental installation having been made in this country by 
 Messrs. Toucey and Buchanan at Spuyten Duyvil Junction, New 
 York City, in 1874, and the first important installations on a 
 commercial basis having been made by the Manhattan Elevated 
 Lines of New York City with machines of the Saxby-Farmer 
 type, built by the Jackson Manufacturing Co. of Harrisburg, 
 Pa., in 1877-78. 
 
 Very soon after American railways had gained a little experi- 
 ence with mechanical interlocking plants, it was felt that 
 there were many situations where great .economies could be 
 effected and more satisfactory operation obtained if switches 
 and signals could be successfully worked by power instead of 
 manually. For precisely the same reason viz : saving of 
 labor that English railways were first led to concentrate in 
 a single frame the theretofore widely separated levers for the 
 operation of switches and signals thus leading up to the 
 idea of interlocking so the much higher cost of labor in the 
 United States than in England caused the American railways 
 to demand an interlocking that would afford means for operat- 
 ing switches and signals over greater distances and with fewer 
 operators than were required under the English method. 
 The first concrete response of the American inventor to this 
 demand was the Hydro-Pneumatic Interlocking installed 
 in 1884 near Bound Brook, N. J., at the crossing of the 
 P. & R. and L. V. R. R. From 1884 to 1891, eighteen Hydro- 
 Pneumatic plants, having 482 levers, were installed on six 
 
GENERAL RAILWAY SIGNAL COMPANY 
 
 railways,' but th4s^ system Ibaving developed many serious 
 defec_vs,^ its^ipveiitOFS devised and in 1891 installed the first 
 elecfro-piteumatk *p1ft& . if ^fre. ^Chicago & Northern Pacific 
 Drawbridge, Chicago. In the following ten years, there 
 were ordered up to June 1, 1900 fifty-four electro- 
 pneumatic plants, having 1,864 levers, for use on thirteen 
 railways. It was felt at this time that while power interlock- 
 ing had been proven to be usable with advantage in a few 
 important situations, it fell far short of accomplishing all that 
 was desired and required of it by the railways, and it was even 
 then believed by some engineers that owing to certain defects 
 and limitations inherent in the electro-pneumatic principle 
 itself, some safer, more reliable and economical system would 
 have to be developed before power interlocking could, with 
 wisdom, be more generally employed. 
 
 Just at this time (May, 1900) a company was formed to 
 develop and exploit the electric interlocking patents now 
 owned by the General Railway Signal Company and embody- 
 ing the now well-known "dynamic indication" principle. In 
 1901 this Company put in service its first electric interlocking 
 plant employing the dynamic indication, at Eau Claire, Wis., 
 on the C. St. P. M. & O. R'y. As might have been expected, 
 in view of the newness of the idea, and of the Company exploit- 
 ing it in opposition to an old-established and rich competitor, 
 its progress was slow; but, the idea being right, its progress 
 has been steady and sure, with the result that in the eleven 
 years since its first plant went into service, it has furnished for 
 use on eighty-three railways in thirty-five States and Provinces 
 of the United States and Canada, 440 of these plants, having 
 21,370 levers. In the sixteen years from the installation of the 
 first commercial pneumatic machine, during which time no 
 competitive power interlocking machine was on the market, 
 the average annual sales were four and five-tenths machines 
 and 147 levers. In the eleven years following the installation 
 of the first commercial dynamic indicating electric interlock- 
 ing machine, and in competition with all other types of 
 power interlocking, our average annual sales have been 
 forty machines and 1,943 levers. With but few exceptions, 
 American railways requiring power interlocking now exclu- 
 sively specify the "all electric," and while the success achieved 
 with our "dynamic indication" system has led a number of 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 companies to devise and offer electric systems, it is believed 
 conservative to state that much more than 90 per cent, of 
 all the electric interlocking in use in the United States is of 
 our manufacture. A more exact statement of percentage 
 cannot be given for the reason that, so far as we have been 
 able to ascertain, other makers of power interlocking plants 
 have not in recent years seen fit to give publicity to the num- 
 ber of power plants and power levers installed by them, though 
 prior to our advent in this field such statements were fre- 
 quently published. It can, however, be positively stated 
 that more of our electric plants and more electric levers have 
 been installed on American railways in this past ten years 
 than of all other types of power interlocking in the past twenty- 
 eight years. 
 
 An evolution so rapid, extensive and radical as this cannot 
 fail to suggest an inquiry into its causes and what bearing 
 they may or should have upon the interlocking practice of the 
 future. 
 
 During the annual meeting of the Railway Signal Associa- 
 tion at Buffalo in October, 1901, one of the principal questions 
 discussed was, "At what leverage is it economical to install 
 power interlocking rather than mechanical." The consensus 
 of opinion then seemed to be that power plants might be 
 economically used where and only where, on account of the 
 size of the machine or density of traffic or for any other reason, 
 more levermen would be required to operate a mechanical 
 than a power machine. At that time the writer hazarded 
 the opinion that in the course of time mere size of plant and 
 density of traffic would cease to be generally regarded as the 
 sole or even as very vital factors in arriving at a choice between 
 power and mechanical interlockings ; that signalmen who were 
 at that time obliged to compare the advantages of mechanical 
 interlocking with those of the only power interlocking with 
 which they then had experience, the electro-pneumatic, might 
 reasonably be expected to change their views very materially 
 when they came to be familiar with the advantages of "all 
 electric" interlocking. How far this forecast, which was then 
 regarded by many able, experienced signalmen as visionary, 
 was warranted may be judged by an examination of tables in 
 this handbook showing hundreds of small and medium sized 
 electric interlocking plants installed by us in the decade that 
 
8 GENERAL RAILWAY SIGNAL COMPANY 
 
 has elapsed since then, thus affording evidence that not only 
 is electric interlocking rapidly displacing all other types of 
 power interlocking but that it is being largely and increasingly 
 used where formerly nothing but mechanical interlocking 
 would have been considered. The writer believes now as he 
 believed ten years ago that certain of the important reasons 
 for this change are found in the following facts: 
 
 Entirely aside from considerations of economical operation 
 that obviously demand the usage of power interlocking at all 
 points where more than one leverman would be required for 
 the operation of a mechanical plant, or where train movements 
 are so numerous as to make the operation of such a plant too 
 great a physical strain upon the operator, there are other and 
 equally important features to be considered with respect to 
 every proposed new interlocking, chief of which is the fact 
 that no purely mechanical interlocking ever devised is any- 
 where near so safe as is the dynamic indicating electric inter- 
 locking. In spite of the now general recognition of this fact, 
 it must be remembered that it was only as the electric inter- 
 locking came to be commonly used and its safety features to 
 be compared with those of straight mechanical interlocking 
 that the defects and dangers of the latter became emphasized 
 by the contrast. Thus, beginning about ten years ago, the 
 realization of this fact by skilled signalmen led them, at first 
 slowly but as time has gone on more and more rapidly, to one 
 'of two practices, viz: the use, on the one hand, of electric 
 interlocking, pure and simple, or, on the other, adding to 
 mechanical interlocking all sorts of electrical apparatus and 
 circuits. Where the latter expedient is adopted, the resultant 
 composite plant requires a maintainer combining the experience 
 of a mechanic and of an electrician, and such men are not 
 numerous. Fifteen years ago the number of young men who 
 had even a rudimentary knowledge of electrics was small; 
 but owing to the enormously increased employment of elec- 
 tricity in telegraphy, telephony, lighting, manufacturing and 
 transportation; to the institution of simple courses in elec- 
 tricity in trade, industrial and correspondence schools; and to 
 the fact that it is easier and takes much less time to acquire 
 a usable working knowledge of electrics than to become a 
 fairly skilled mechanic most railways now find it possible 
 to procure, at the prevailing wage rate, men capable of 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 maintaining electrical rather than mechanical installations 
 particularly since the automobile and kindred industries have 
 created such an unprecedented demand, at high wages, for 
 mechanics. 
 
 Another fact having an important bearing on this phase of 
 our subject is this : American block signal practice, like its 
 interlocking practice, was originally copied from the English, 
 who employed the manual system. In block signaling, as was 
 the case in interlocking, the American demand for labor 
 saving devices early led to the invention of power operated 
 automatic block signals, the first of which to be employed 
 on a considerable scale were of the pneumatic type. Now, 
 in automatic block signaling, as in interlocking, the electric is 
 almost entirely supplanting the electro-pneumatic, and few, if 
 any, American railways are now considering anything but 
 electric signals for new block work. Such signals are now 
 used on upwards of 35,000 miles of American railway, and 
 large additions are being made thereto annually. It will 
 hardly be denied by any engineer skilled in signaling that 
 every interlocking plant located in automatic, electric, block 
 signaled territory should be electric, since, if for no other 
 reasons, it can be more simply installed, more economically 
 maintained and more reliably operated than a mechanical or 
 any other type of interlocking which would require the mixing 
 in with the necessary electric block devices of other types of 
 apparatus requiring maintainers and repairmen having needed 
 training in two or more trades rather than in one. This is a 
 consideration, which, quite apart from that of maximum 
 safety, has led many railways to the installation of a great 
 deal of electric interlocking in automatic block signaled dis- 
 tricts and which is influencing them and others to take like 
 action where automatic block signaling, though not in imme- 
 diate prospect, may be put in within a few years. 
 
 Thus it has come to pass that of the railway men who still 
 feel that the mechanical interlocking when provided with 
 various electrical adjuncts may be made to be almost if not 
 quite as safe as the "all electric plant," more and more are 
 coming to realize that simplicity, economy and reliability 
 demand the usage of the electric interlocking in preference to 
 any others, particularly as a mechanical plant, even when 
 equipped with the most elaborate system of electrical adjuncts, 
 
10 GENERAL RAILWAY SIGNAL COMPANY 
 
 has not changed its nature but still remains a mechanical 
 plant, subject to most of the operating difficulties inseparable 
 from such a plant. 
 
 Another situation that has largely influenced the adoption 
 of electric interlocking is the following: Up to the time of 
 the introduction of electric interlocking, it was the rule, rather 
 than the exception, for American railways to operate from 
 interlocking machines at ordinary crossings and junctions 
 such switches as were within 700 to 800 feet of it, but not to 
 operate or adequately signal more distant switches. Where 
 any connection existed between such distant switches and 
 the interlocking it was usually no more than that established 
 by having an electric circuit controller on such a switch by 
 means of which an electro-magnetically slotted distant signal 
 alone was prevented from giving its proceed indication when 
 the switch was open between it and the home signal. It 
 was claimed by the railways, not without reason, that it was 
 too difficult and costly, and in some instances impossible, to 
 satisfactorily operate such switches from a single machine 
 and that it would be the height of folly for them to install one 
 or more additional machines merely for the sake of operating 
 these switches, the interlocking of which would not have been 
 at all considered at the moment except for their proximity to 
 junctions or crossings they were obliged to interlock. Gradu- 
 ally, however, for one or another reason, American practice is 
 coming more and more approximate to that of England, 
 where every main line switch on a passenger carrying road has 
 to be properly signaled and interlocked, and coincident with 
 and probably largely responsible for this changed attitude of 
 the American railways is the now almost universal recognition 
 of the fact that electric interlocking alone affords the means for 
 successfully accomplishing this in the United States without 
 excessive cost for both installation and operation. Many of 
 our electric plants have for years satisfactorily operated 
 switches, together with their allied signals, located from one 
 to six thousand feet from the interlocking machine, some- 
 times with tunnels or other obstructions to view, intervening 
 between the interlocking station and the switches. In fact, 
 as temperature changes, no matter how great or how sudden, 
 do not in any degree affect the operation of our electric 
 plants, they being absolutely free from such disorders as, in a 
 
ELECTRIC INTERLOCKING HANDBOOK 11 
 
 mechanical plant, occur because of contraction or expansion of 
 parts connecting the interlocking levers with the switches 
 and signals, and as the "dynamic indication" features and the 
 "illuminated track diagrams" make it wholly unnecessary for 
 the operator to see tracks, trains, switches, or signals there 
 is absolutely no limit to the distance at which such switches and 
 signals can be safely, reliably and expeditiously worked by means 
 of our electric interlocking. As an illustration, it may be 
 of interest to note here that by far the largest interlocking plant 
 in the world, one of our dynamic indicating type, at the Grand 
 Central Terminal of the N. Y. C. & H. R. R. R.,New York City, is 
 operated most successfully under conditions where it is impos- 
 sible to have any view from the interlocking station of trains, 
 tracks, switches, or signals. 
 
 It would be possible, as is recognized by all who have closely 
 observed and carefully studied the trend of American signal 
 practice for a score or more of years, to cite almost number- 
 less additional conditions each of which has had some part, 
 big or little, in determining why it is that electric interlocking 
 has been and is being increasingly installed in units varying 
 all the way from four to four hundred levers; why it is 
 used with equally satisfactory results at small junctions, 
 yards and crossings where traffic is light ; at hundreds of 
 points of medium traffic where machines of from sixteen 
 to forty-eight levers are required and at the busiest and 
 largest terminals ; but such a citation would be long, and after 
 all, the whole matter can be briefly summed up by saying that 
 the reasons why more of our dynamic indicating electric inter- 
 locking machines have been installed in the last ten years 
 than of all other types of power interlocking in the past twenty- 
 eight years, and why they are being so largely employed 
 where formerly only mechanical machines would have been 
 considered are that experience has fully demonstrated that 
 wherever and under whatever conditions of traffic or climate 
 our dynamic indicating electric system has been 'tried it has 
 been found superior to every other type of interlocking, in 
 safety, reliability, economy and rapidity. of operation and in 
 its adaptability to every present and prospective need of the 
 user. For these reasons, the writer hazards the prediction 
 that within the next ten years many important American 
 railways will closely approximate to a condition where every 
 
12 GENERAL RAILWAY SIGNAL COMPANY 
 
 block signal and every interlocking machine, large and small, 
 over long stretches of their main line will be controlled, operated 
 and lighted by power supplied from central energy stations, 
 and where, in consequence, mechanical or any other than 
 electric interlocking will be almost as much a thing of the 
 past as is the "horse car" on the street railways of to-day. 
 To such readers as may be inclined to regard this forecast as 
 wild or visionary, the writer suggests the perusal of the preface 
 prepared by him for the 1902 Electric Interlocking Catalogue, 
 and that this may be readily done, that preface is reprinted 
 herein (see page 405). After noting the forecasts made in 
 1902 and finding that every claim therein advanced for the 
 then newly introduced electric interlocking system has been 
 fully met and that its general adoption has more than realized 
 the most sanguine expectations then entertained for it the 
 reader may be less inclined to be over skeptical as to the pre- 
 diction made for the coming decade. 
 
 To meet the requirements of the many present and prospec- 
 tive users of our dynamic indication electric interlocking, we 
 have prepared this Handbook, wherein it is sought to furnish 
 data that will be useful to all those seeking a true understanding 
 of the dynamic indication principle, and to those who are 
 required to prepare bills of material for, or to install, operate 
 or maintain our electric interlocking. 
 
 W. W. S. 
 
SECTION I 
 
 G. R. S. ELECTRIC INTERLOCKING SYSTEM 
 
 SETTING FORTH THE PRINCIPLES IN- 
 VOLVED AND GIVING A BRIEF DE- 
 SCRIPTION OF THE APPLIANCES USED 
 
G. R. S. ELECTRIC INTERLOCKING 
 SYSTEM 
 
 REQUISITES OF A PROPERLY DESIGNED INTERLOCKING 
 
 SYSTEM 
 
 INTERLOCKED switch and signal appliances were first de- 
 vised and used at junctions and terminal points for the pur- 
 pose of reducing the number of men employed to go from 
 switch to switch, throw them by hand and then give a hand sig- 
 nal for the train to proceed over the route thus lined up. It was 
 soon found that operating the switches and signals from a central 
 point under the control of the levers in an interlocking machine 
 greatly expedited the handling of traffic. By far the greatest 
 accomplishment of interlocking, however, was the addition of 
 an enormous factor of safety at such points to train operation. 
 
 Inherent in the system of mechanical interlocking which 
 first was employed to control the switch and signal functions 
 were certain recognized shortcomings as regards safety and 
 facility of operation. 
 
 Systems of power interlocking in the field prior to the intro- 
 duction of the electric dynamic indication system, now owned 
 and manufactured by the General Railway Signal Company, 
 although giving increased facility of operation, did not and 
 do not provide the greatest safety obtainable with this increased 
 facility. 
 
 The features of vital importance in considering the merits 
 of any system of power interlocking are those which are 
 designed to give the greatest)* measure of safety together with 
 facility of operation. The two features most important to 
 safety are : 
 
 First The means provided to check the correspondence 
 of movement between lever and the switch, signal, or other 
 function controlled by it. 
 
 Second The means for preventing unauthorized move- 
 ment of switches, signals, or other controlled functions. 
 
 The reliability of the means by which the above protection is 
 secured determines more than anything else the safety of a 
 given system of interlocking. In fact, this is so vital that an 
 interlocking plant without a thoroughly dependable system 
 for insuring correspondence between its levers and the operated 
 functions, and for preventing the unauthorized movements of 
 such functions, is absolutely unsafe. 
 
 The G. R. S. electric interlocking system fully meets the 
 first important requirement of checking the correspondence of 
 movement between lever and operated function by means of 
 the dynamic indication, energy for which is furnished by a 
 momentary dynamic current generated by the motor of the 
 operated function itself when and only when the actual opera- 
 tion of such function shall have been properly completed. 
 Contrast this with systems employing A. C. or battery 
 
16 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 indication, in which the indication is secured from energy 
 existent at the function prior to and during the movement of 
 that function and dependent only on the closing of a single 
 break in the indication circuit. 
 
 The use of the dynamic current, generated by the momen- 
 tum of the motor of the operated unit at one end of the circuit 
 and so giving the desired indication at the lever at the other end 
 of the circuit, prevents the receipt of a false indication due to a 
 
 FIG. 1. 
 
 LAKE STREET INTERLOCKING PLANT. 
 TERMINAL, C. & N. W. R'Y 
 
 CHICAGO 
 
 cross between the wires of the circuit, and is, therefore, correct 
 in principle. 
 
 The unauthorized movement of switches or derails, or the 
 improper clearing of the signals is prevented by a simple and 
 effective method of cross protection, the basis for which is 
 inherent in an electric interlocking system using dynamic 
 indication. It is a notable feature that the second require- 
 ment is met by a means in which all the contacts required for 
 this protection form a part of the operating circuit, thus check- 
 ing their integrity at each operation. 
 
 In order to fully consider the advantages of the G. R. S. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 17 
 
 system of electric interlocking, its elements are described in 
 more detail as outlined below. 
 
 ELEMENTS OF G. R. S. ELECTRIC INTERLOCKING 
 
 SYSTEM 
 
 A complete installation of the General Railway Signal Com- 
 pany's electric interlocking system comprises the following 
 elements : 
 
 First A source of power consisting of a storage battery 
 with its charging unit. 
 
 FIG. 2. COLLIN-W 
 
 3RLOCKING PLANT. L. S. & M. S. R*Y 
 
 Second Power control apparatus introduced between the 
 source of power and the interlocking machine. 
 
 Third An interlocking machine with levers for the control 
 of the switch and signal mechanisms. 
 
 Fourth Switch mechanisms, their operating and indicat- 
 ing circuits. 
 
 Fifth Signal mechanisms, their operating and indicating 
 circuits. 
 
 Sixth Means for the prevention of unauthorized move- 
 ment of any function. 
 
 In connection with such a system may be installed such 
 accessories in the way of track circuits, detector locking, 
 route locking, indicators, annunciators, etc., as may be de- 
 sired at each individual installation. 
 
18 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 SOURCE OF POWER 
 
 The source of power, from which the G. R. S. system 
 of electric interlocking is operated, consists of a storage 
 battery having an approximate working potential of 110 
 volts, this battery being charged by a power generating 
 unit, which frequently is a generator driven by a small 
 gasoline engine. 
 
 FIG. 3. MODEL 2 UNIT LEVER TYPE INTERLOCKING MACHINE. 
 
 LAKE STREET INTERLOCKING PLANT, CHICAGO 
 
 TERMINAL, C & N. W. R'Y 
 
 POWER CONTROL APPARATUS 
 
 Power is delivered to the interlocking machine under the 
 control of protective apparatus, mounted on suitable switch- 
 boards. 
 
 INTERLOCKING MACHINE 
 
 The operation of each switch and signal function is controlled 
 by levers, which with their respective locking tappets, indica- 
 tion magnets and circuit controllers, are mounted in a common 
 frame, the whole being known as an interlocking machine. 
 
 Starting with the lever in either of its extreme positions, 
 the stroke of the lever is divided into two movements. The 
 first movement locks all levers conflicting with its new position 
 and operates the function. The second and final movement 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 19 
 
 of the stroke releases such levers, hitherto locked, as do not 
 conflict with its new position. Except in the reverse position 
 of a signal lever, this final movement can be made after, and 
 only after, the dynamic indication has been received certifying 
 that the operated function has assumed a position correspond- 
 ing with that of its lever. 
 
 SWITCH MECHANISM ITS OPERATING AND INDICATING 
 CIRCUITS 
 
 Each switch and derail is thrown and locked by a switch 
 and lock movement driven by a series wound direct current 
 
 FIG. 4. 
 
 MODEL 4 SWITCH MACHINES HIGH BRIDGE, TOWER "A," 
 ELECTRIC DIVISION, N. Y. C. & H. R. R. R. 
 
 motor. Two wires are used for its control, one for the normal 
 and the other for the reverse operation. These same wires 
 are used for indicating purposes, the normal control wire being 
 used for the reverse indication and the reverse control for the 
 normal indication. The circuit is connected to main common 
 at the switch location. 
 
 The circuits for a switch are shown in simplified form in 
 Fig. 5, the operating and indicating currents in the different 
 diagrams being shown by the red lines. 
 
 When the switch (normal position) is to be operated, the 
 first movement of the stroke of the controlling lever carries it 
 as far as the reverse indication position and permits current to 
 flow as shown in Fig. 5B, which causes the mechanism to move 
 the switch points to the reverse position and lock them in 
 that position. When this movement has been completed the 
 
20 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 5viiich Mechanism 
 ' Motor-Veld " 
 
 Main Common 
 
 Reverse Control & * 
 Normal Ind rti 
 
 lever Full Normal 5nitch Mormal 
 
 A - At Rtst- No Current floning 
 
 
 Lever 
 
 Indication Position 
 
 B - Operdting 
 
 Snitch leaving 
 Normal Position 
 
 Lever at Reverse 
 Indication Position 
 C - Indicating 
 
 5nitch Reverse 
 
 Til 5P ^* 
 
 Lever Full Reverse Snitch Reverse 
 
 D - At Rest- No Current flowing 
 
 FIG. 5. SIMPLIFIED CIRCUITS FOR MODEL 2 OR MODEL 4 
 SWITCH MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 21 
 
 circuit through the switch motor is automatically changed, 
 disconnecting the motor from battery and connecting it in a 
 closed circuit including the indication magnet (Fig. 5C) ; at the 
 same time the armature terminals are reversed for indication 
 purposes, this leaving the motor connections in proper position 
 for the next operation. The motor (now a generator) with 
 the momentum acquired during the operation of the switch 
 movement, generates a momentary current which energizes 
 
 FIG. 6. 
 
 MODEL 2 SWITCH MACHINES. MAYFAIR INTERLOCKING 
 PLANT, C. & N. W. R'Y 
 
 the indication magnet, thus permitting the final movement of 
 the lever to be completed (Fig. 5D). 
 
 The operation of the lever and function from the reverse to 
 the normal position is accomplished in the same, manner. 
 
 A useful feature, not usually obtainable in other power sys- 
 tems, is that the movement of the switch points may be re- 
 versed at any portion of their travel at will by the operator, 
 and the lever movement completed upon the switch points 
 assuming a position corresponding with that of the lever, 
 irrespective of the direction of the first movement made by 
 the lever. 
 
 The complete switch operation and final movement of the 
 
22 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 lever may be accomplished in from 
 two to two and one-half seconds, 
 the indication being practically 
 instantaneous with the completion of 
 the switch operation. 
 
 SIGNAL MECHANISM ITS OPERA- 
 TING AND INDICATING CIRCUITS 
 
 The description of signal mechan- 
 isms will be confined to the non- 
 automatic, two position signal, as this 
 will show the principles involved in 
 all types of motor driven signals now 
 used in the system. 
 
 This signal is operated by a 
 mechanism in which the motor is 
 directly connected to the semaphore 
 shaft through low reduction gearing. 
 The signal is held at proceed during 
 such time as its controlling lever is 
 in the reverse position solely by a 
 dense magnetic flux thrown across 
 the air gap between the motor arma- 
 ture and the field pole pieces (holding 
 field pole surfaces are serrated) by 
 cutting the windings on the holding 
 field poles in series with the operating 
 field windings. 
 
 Each signal requires for its opera- 
 tion and indication one wire and a 
 connection to the common return wire. 
 A simplified circuit for this type of 
 signal is shown in Fig. 8, the path 
 taken by the operating, holding, and 
 indicating current in the different dia- 
 grams being shown by the red lines. 
 Upon reversal of the controlling lever, the signal 
 mechanism will receive current as shown in Fig. 8B, 
 this causing it to move the blade to the proceed 
 position. When the signal blade has assumed this 
 position the circuit breaker cuts in series with the 
 operating field and armature, the high-resistance 
 holding field, thereby retaining the signal arm at 
 proceed (Fig. 8C). The holding field windings have 
 a high resistance, which reduces the current to that 
 employed for holding the signal at proceed. 
 
 When the signal lever is placed in the normal indicating 
 position, energy is cut off from the motor and the blade returns 
 to the stop position by gravity, causing the signal mechanism 
 and motor armature to revolve backward to their original 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 23 
 
 Mechanism 
 
 R N 
 
 Control and Indication 
 
 FT 
 
 T-T Indication 
 I |[[l.lil 1 
 
 rloldinb 
 Field 
 
 ;0pen 
 > Field 
 
 Mam Common 
 
 Motor __ 
 Armature 
 
 Lever full normal 5'tyial at stop 
 
 A - At rest -no current flowing 
 
 R M 
 
 ^Ulll 
 
 
 Lever -full reverse 
 
 Lever -full reverse 
 
 - Operating 
 
 C - Holding 
 
 LJ 
 
 Signal leaving stop position 
 
 Signal or proceed 
 
 Lfi 
 
 Lever at normal 
 indicating position 
 
 . , n<jicat , n ^ 
 
 lO'(Approx) 
 from stop position 
 
 'LJ 
 
 Lever full normal 
 
 E- At rest -no current 
 
 Signal at stop 
 
 FIG. 8. SIMPLIFIED CIRCUITS FOR MODEL 2A, NON-AUTOMATIC, 
 Two POSITION SIGNAL 
 
24 GENERAL RAILWAY SIGNAL COMPANY 
 
 position. Just as the blade reaches the stop position the 
 action of the circuit breaker connects the motor armature and 
 operating field into their original closed circuit (Fig. 8D), in 
 which is included the indication magnet. Due to its acquired 
 momentum the motor (now a generator) produces an indica- 
 tion current in this circuit which permits the controlling lever 
 to be moved to the full normal position (Fig. 8E). 
 
 It is universal practice to indicate the signal lever in the 
 normal position only, this insuring that the signal blade is in 
 the stop position before releasing any of the switch levers in 
 the route governed. No safety features are sacrificed if the 
 signal fails to assume the proceed position upon reversal of its 
 controlling lever. 
 
 Dynamic Indication. The use of the dynamic indication as 
 described above has the following advantages : 
 
 First The indication is not secured from energy existent 
 at the function prior to the movement of that function and 
 dependent only on the closing of a single break in the indica- 
 tion circuit, as is the case in A. C. and battery indication 
 systems; but being a dynamic current generated by the mo- 
 mentum of the motor, it can be secured only after actual opera- 
 tion of the function. 
 
 Second The energy for the indication is developed at one 
 end of the circuit and the indication magnet is located at the 
 other ; hence a cross between wires prevents indication, whereas 
 in systems which use the battery in the interlocking station 
 for indication a cross tends to cause indication. 
 
 Third No extra power is required for indication. 
 
 Fourth The indication current ceases automatically with 
 the stopping of the motor and, therefore, no auxiliary devices 
 or operations are necessary to cause it to cease. 
 
 Fifth No additional wires are required for indication. 
 
 Sixth The generated indication current automatically 
 "snubs" the motor and causes it to stop without shock and 
 without the use of buffers, springs, or auxiliary snubbing 
 circuits. 
 
 Seventh The indicating circuit is automatically checked 
 as to its integrity every time an indication is received, and 
 being a closed circuit of low resistance around the motor, it 
 shields the motor while at rest from all foreign currents. This 
 inherently provides the foundation for the simple and effective 
 cross protection system employed with the G. R. S. electrie 
 interlocking. 
 
 MEANS FOR THE PREVENTION OF UNAUTHORIZED 
 FUNCTION MOVEMENTS 
 
 The cross protection system prevents the unauthorized 
 movement of any switch, signal, or other function due to 
 energy improperly applied to its circuit through a cross between 
 
ELECTRIC INTERLOCKING HANDBOOK 25 
 
 wires, by cutting off current from the function in the event of 
 such an occurrence. 
 
 As explained under "Dynamic Indication," all functions are 
 normally on a closed circuit of low resistance. Connected in 
 each of these circuits is a small polarized relay through which 
 all operating and indicating currents must pass in a direction 
 to maintain the relay's contact closed, while all currents from 
 an unauthorized source must pass in the opposite direction 
 thus instantly opening the contact. Through all these con- 
 
 FIG. 9. MODEL 2A SIGNALS. CHICAGO TERMINAL, C. & N. W. R'Y 
 
 tacts in series is controlled the retaining magnet of an electro- 
 mechanical circuit breaker, which is introduced into the power 
 mains between the storage battery and the interlocking ma- 
 chine. Hence, a cross onto the circuit of a function at rest, 
 by opening the contact of its polarized relay, opens the electro- 
 mechanical circuit breaker, cuts power off from the Interlocking 
 machine and thereby prevents any improper movement of 
 the function. 
 
 In a simple plant a single electro-mechanical circuit breaker 
 is ordinarily installed, this preventing the movement of all 
 functions at any time the circuit breaker may be open. Where 
 traffic conditions warrant the increased expenditure, additional 
 circuit breakers may be provided to permit of dividing the 
 plant into as many sections as may be desired. 
 
26 GENERAL RAILWAY SIGNAL COMPANY 
 
 The design of the circuit breaker is such as to make it impos- 
 sible for a leverman (thoughtlessly or through ignorance) to 
 prevent it from performing its function. 
 
 Cross Protection. The cross protection secured with the 
 G. R. S. electric interlocking system has the following advantages : 
 
 First All contacts and connections depended upon for 
 cross protection are either on closed circuit or are used for opera- 
 tion and indication, so that any failure of these contacts and 
 connections, which would impair their usefulness as a cross- 
 protective medium, also prevent operation and indication. 
 Hence they are under a constant, automatic check without the 
 use of any extra contrivances for this purpose. 
 
 Second Wire insulation is not depended upon for cross 
 protection. This system at certain installations has given 
 years of safe operation with wire, the insulation of which does 
 not measure up to the usual standard. 
 
 Third The cross protective apparatus consists of the polar- 
 ized relays and apparatus on the operating board; no wire or 
 additional appliances are required outside of the station to 
 secure this protection other than the simple apparatus already 
 installed for the operation of the various functions. 
 
 Fourth The switch and signal motors, being of low resist- 
 ance, require a current of several amperes for their operation ; 
 therefore, a cross to produce the operation of any function 
 must be of very low resistance. Thus it will be seen that the 
 system is not sensitive to the effect of crossed wires. Not- 
 withstanding this fact, an efficient system of cross protection 
 is provided in the G. R. S. system. 
 
 CONCLUSION 
 
 The comparative value of different systems of interlocking 
 may be accurately determined by a consideration of but four 
 essential factors. These four factors must be present in any 
 interlocking system to warrant its use. They are: Safety, 
 Facility, Reliability, and Economy. 
 
 Safety. 
 
 The factor first demanding consideration is that of safety. 
 This essential of an interlocking system overshadows all other 
 considerations, and in the ideal system the safety must be 
 absolute. The G. R. S. electric interlocking with dynamic 
 indication provides a factor of safety that is the closest approxi- 
 mation to the ideal known to those skilled in the signaling art. 
 This is verified by the statement made by a disinterested 
 committee in an able report based on a study of various types 
 of power interlocking systems, presented to the International 
 Congress of Application of Electricity held at Marseilles, 
 France, in 1908, this statement being worded as follows: 
 
 "The safety of an interlocking plant is dependent solely 
 
ELECTRIC INTERLOCKING HANDBOOK 27 
 
 upon the existence of a positive, reliable indication of corre- 
 spondence between the position of a lever and its controlled 
 function. * * * the Taylor (G. R. S.) system meets 
 even this requirement. In fact it insures absolute reliability 
 of indication by employing the motor as a means for generat- 
 ing the required current as explained above so that it is 
 certain that the indication given cannot ever be due to de- 
 fects in wiring. Then, this indication having been received 
 in the interlocking station, it establishes a control which is 
 permanently maintained by a source of energy located in 
 the station. Moreover this permanent control utilizes identi- 
 cally the same circuit that is employed in the normal operation 
 of the function; in consequence, the circuit used is one that 
 must be maintained in good, operative condition for each 
 movement of the function. 
 
 It will therefore be seen that by virtue of this arrangement, 
 the Taylor (G. R. S.) system insures permanency of indica- 
 tion ; that it is economical since it utilizes the operating source 
 of energy located in the station, and that it is absolutely 
 trustworthy since it is in no sense subject to any danger from 
 crossed or grounded wires." 
 
 Facility. 
 
 The facility offered by any given interlocking system depends 
 largely upon : first, the rapidity of operation of the individual 
 functions, and second, its capabilities for permitting simulta- 
 neous operation of a number of functions. In such a system 
 the amount of time required to move traffic is reduced to a 
 minimum. 
 
 By incorporating the above two features in the design of the 
 system, the G. R. S. electric interlocking fully meets all 
 demands for facility of operation. This has been repeatedly 
 proven by the performance of the system at points where 
 the traffic conditions have imposed the most exacting operating 
 requirements. 
 
 Reliability. 
 
 The reliability of an interlocking system is primarily de- 
 pendent upon the fundamental principle underlying its opera- 
 tion, and in general it may be said, without fear of contradic- 
 tion, that unless the principle is simple, it is not correct. The 
 correct principle having been adopted, the reliability of the 
 system then depends upon a proper design of each and every 
 part of the devices used to put the principle into practice. 
 
 It is recognized that the principles of operation of the G. R. S. 
 interlocking are correct, and the circuits simple to an extreme 
 degree, no radical changes having been made in either since 
 the introduction of the system. The parts of all apparatus are 
 strong and rugged, and capable of performing their functions 
 without undue wear and tear; furthermore, the design of all 
 parts of the apparatus has been so very carefully perfected 
 
28 GENERAL RAILWAY SIGNAL COMPANY 
 
 during some twelve years' experience that their form now 
 represents the very best engineering practice. 
 
 As an example of the system's reliability of operation, 
 records published by an important railroad covering a period 
 of one year show a total of 2,615,406 switch operations, in 
 which the number of imperfect operations were so few that 
 they did not exceed one to every 186,814, and the total traffic 
 detention for the year was only seventy and one-half minutes. 
 
 Economy. 
 
 Due to the correct design of the apparatus and resultant 
 long life of same, the cost of renewals is practically negligible. 
 This, together with the marked simplicity of the circuits, 
 insures a cost of maintenance much less than in any other 
 system of interlocking. The cost of operating also shows a 
 corresponding economy, not only by the fewer number of 
 men required for the operation of the power system as com- 
 pared with the mechanical system, but also in the cost of 
 power when compared with other power systems. Carefully 
 kept railroad records show that the power cost is but one cent 
 for 300 to 400 switch and signal movements. 
 
 A most minute analysis and extended description of the 
 merits and advantages of any given system of interlocking 
 fails to be convincing unless the truth of all the statements 
 are thoroughly substantiated. That the above statements 
 concerning the G. R. S. electric interlocking system must 
 be true, is shown by the well nigh universal adoption of the 
 system, both for large and for small installations. 
 
 Four hundred and forty installations have been made or 
 are under contract on some eighty different railroads in all 
 parts of the United States and Canada, a considerable num- 
 ber of plants also having been installed in Europe. On the 
 basis that one interlocking lever in use for one year equals 
 one lever year, the G. R. S. system now shows a record of 
 110,000 lever years. 
 
 The satisfactory operation of these installations, large and 
 small, under widely varying conditions of both climate and 
 traffic, is a most convincing demonstration that every demand 
 for an interlocking system has been met in a most satisfactory 
 manner by the G. R. S. electric interlocking. 
 
SECTION II 
 
 G. R. S. ELECTRIC INTERLOCKING 
 APPLIANCES 
 
 GIVING A DESCRIPTION OF THE AP- 
 PLIANCES USED AND THEIR METHOD 
 OF OPERATION 
 
INTERLOCKING STATIONS 
 THE INTERLOCKING STATION 
 
 THE interlocking station, from which the various switch 
 and signal functions of the plant are operated, is usually 
 a two-story building similar in appearance to those used at 
 mechanical plants. The station does not require the same heavy 
 construction used in mechanical work on account of the fact that 
 the movement of the levers of the electric interlocking machine 
 puts absolutely no strain on the building. It should be noted 
 
 FIG. 10. HACKENSACK DRAW BRIDGE INTERLOCKING 
 STATION. ERIE R. R. 
 
 in this connection, however, that the frame building generally 
 used in the earlier installations is of late years being largely 
 supplanted by the more substantial brick or concrete structure. 
 
 SIZE OF THE BUILDING 
 
 The station can be much smaller than that required for 
 mechanical plants of the same number of functions due to the 
 smaller size of the interlocking machine. The length of the 
 building is usually determined by the size of the interlocking 
 machine; the width, however, is generally in excess of that 
 required for the machine, being increased to accommodate 
 the table, lockers, etc., needed by the operator, and on the 
 
32 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Jol 
 
 
 
 \ i 
 
 t V fL* , - 
 
 Desk 
 
 D 
 
 c 
 V 
 
 3 
 j 
 
 >-. 
 
 
 
 . "' 0" r 
 
 
 
 
 ^ Front of Machine 
 
 
 
 
 a 
 It 
 
 , 80 Space Unit Lever "type 
 ' Interlocking Machine 
 
 
 
 
 
 
 'c 
 
 f 
 
 i 
 
 loft' ft" 
 
 
 
 HO 1 jcO 1 
 L' Operating Snitch Board 
 . m ..Indicator Cabinet 
 
 rl 33 i i ^ 
 
 SECOND FLOOR. 
 
 
 [ 
 
 \ rork Bench /^~^\ / 
 \ (Sfove ) / 
 
 
 
 
 v \_y 
 
 
 
 
 \ 
 
 t-' n 
 
 
 
 
 
 
 
 / 
 
 
 
 
 Engine Gencrdftor 
 / 
 
 Battery 
 
 
 
 
 Cupboard 
 
 
 
 Duct for nires to ) *? 
 
 
 
 
 Inter locKmg Machine^ i ^ | r 
 
 
 
 
 Relay Gabinet| N 1 1 \ 
 
 
 Track Side 
 FIRST FLOOR.. 
 
 FIG. 11. TYPICAL PLANS OF INTERLOCKING STATION FOR 
 EIGHTY LEVER MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 33 
 
 larger installations to provide room for a train director and 
 telegraph operator. 
 
 When it is desired to have shops and storerooms located 
 in the interlocking station, the machine ceases to be the 
 determining factor in the size of the building, unless the 
 additional space for these rooms is secured by using a three- 
 story building as in the case of the Lake Street Station 
 shown in Fig. 13. It is also true that on small plants the 
 location of the storage battery and power apparatus in the 
 lower story of the station is apt to make it necessary for 
 
 FIG. 12. SOUTH ENGLEWOOD INTERLOCKING STATION 
 AND POWER HOUSE, C. R. I. & P. R'Y 
 
 the building to have larger dimensions than those required 
 for the interlocking machine. 
 
 ARRANGEMENT OF APPARATUS 
 
 The different methods of arranging the apparatus in the 
 station is shown by Figs. 11, 13 and 15, which may be 
 taken as typical of small, intermediate and large sized stations 
 respectively. By reference to these illustrations it will be 
 seen that the general practice is to locate the interlocking 
 machine, the operating switchboard and such accessory appa- 
 ratus as track diagrams, indicators, etc., on the top floor, the 
 storage battery in a room by itself on the lower floor, and the 
 charging apparatus on the same floor with the battery or in a 
 building separate from the interlocking station. 
 
34 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 13. PLAN OP LAKE STREET INTERLOCKING STATION. 
 CHICAGO TERMINAL, C. & N. W. R'r 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 35 
 
 POINTS TO BE NOTED 
 
 The design of the building should be such that the floors 
 will be sufficiently rigid to properly support the machine. 
 
 Wherever possible the general practice is to have the operat- 
 ing room liberally supplied with windows to permit the operator 
 to have a clear view of the tracks throughout the plant. 
 
 It is highly desirable that the conduits or ducts provided for 
 the runs of electrical conductors about the tower should be 
 
 FIG. 14. 
 
 LAKE STREET INTERLOCKING STATION- CHICAGO 
 TERMINAL, C. & N. W. R'Y 
 
 of sufficient capacity to have 25 per cent, spare space after 
 all wiring is in place. 
 
 No special foundations are required for the apparatus used 
 in an electric plant, except when the charging generator is 
 driven by an engine, in which case a substantial foundation 
 should be provided for the engine so that the building will 
 not be subjected to any vibration during its operation. 
 
36 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 1 
 
 
 
 
 i 
 
 Cl 
 Cl 
 
 1 
 
 c 
 
 Cl 
 Cl 
 
 
 
 ~-.>,_l 
 
POWER PLANTS AND SWITCHBOARDS 
 COMPOSITION 
 
 THE power equipment for the G. R. S. Electric Interlocking 
 plants is usually composed of a storage battery, suitable 
 means for charging the battery, a power switchboard and an 
 operating switchboard. 
 
 FIG. 16. INTERLOCKING BATTERY (400 AMPERE HOURS) 
 INSTALLED ON BATTERY RACKS 
 
 LOCATION 
 
 The location of the units which compose the power plant 
 varies considerably on different installations. The operating 
 switchboard is always located in the operating room, being 
 placed whenever possible in such a position that its meters 
 and indicating lamp are in full view of the leverman when 
 manipulating the levers of the machine. The storage battery- 
 is ordinarily located on the first floor of the interlocking 
 station. The power switchboard and charging apparatus at 
 many installations are placed in a room adjacent to that occu- 
 pied by the battery, although building restrictions or the need 
 of space for workrooms or offices often make it necessary to 
 house this apparatus in a building separate from the inter- 
 locking station. 
 
38 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 BATTERIES 
 
 The interlocking battery usually consists of one set of 
 storage cells having a potential of 110 volts. A second or 
 duplicate battery is furnished on a few of the larger installa- 
 tions to insure sufficient power for any possible emergency. 
 
 FIG. 17. 
 
 INTERLOCKING BATTERY (120 AMPERE HOURS) 
 INSTALLED IN BATTERY CUPBOARD 
 
 The capacity of the battery used should be based on the num- 
 ber of function movements between battery charges and the 
 current used for all auxiliary apparatus. 
 
 The battery as usually installed comprises fifty-five lead 
 type storage cells. When long runs of conductors between 
 the battery and interlocking machine are necessary, one or 
 more cells are sometimes added to the battery to compensate 
 for the voltage drop which occurs in the conductors when- 
 ever several switch functions are operated at the same time. 
 
ELECTRIC INTERLOCKING HANDBOOK 39 
 
 This may also be taken care of by using wires of larger carry- 
 ing capacity than would otherwise be necessary. 
 
 Low voltage batteries are frequently installed to operate 
 annunciators, indicators, relays and electric locks, and occa- 
 sionally to serve the track circuits of the interlocking plant. 
 Operating the relays, indicators, etc., from a low voltage 
 battery usually proves more economical than to take current 
 for that purpose from the main battery. 
 
 CHARGING APPARATUS 
 
 The charging of the battery is generally accomplished by 
 means of a shunt wound generator driven by an electric motor 
 or gasoline engine. The generator should be capable of de- 
 
 FIG. 18. G.R.S. D.C. GENERATOR 
 
 livering the desired current at any voltage from 110 to 160, 
 the current output being determined by the charging rate 
 recommended for the batteries installed. In 'the event of the 
 generator being used to supply current for lighting, either 
 regularly or in case of emergency, the additional capacity 
 required for the purpose should not be overlooked. 
 
 When the generator is located at some distance from the 
 battery it is necessary to take care of the voltage drop due 
 to the resistance of the charging circuit, either by increasing 
 the size of the conductors or by using a generator having a 
 higher voltage rating. 
 
 Whenever current of suitable voltage and from a reli- 
 able source can be secured at reasonable rates, its use is rec- 
 ommended. The motor-driven generator, referred to above, 
 is usable with either alternating or direct current, the generator 
 being shaft or belt connected to the motor as proves most 
 
40 GENERAL RAILWAY SIGNAL COMPANY 
 
 convenient. If the current supply is direct, a charging rheostat 
 can be used for the battery charging, or if alternating, a 
 rectifier employed. 
 
 Charging rheostats, having no moving parts, are the simplest 
 and most reliable of the different types of apparatus which can 
 be used in this work. They are, however, very much less 
 efficient than other battery charging devices, and therefore 
 should not be used when the cost of power is an item to be 
 considered. 
 
 Motor generator sets are compact, reliable and, furthermore, 
 highly efficient. When used on this type of work, they can 
 
 FIG. 19. G. R. S. D. C.-D. C. MOTOR GENERATOR SET 
 
 be designed for operation on voltages as high as 550, the 
 lower voltages, however, being recommended as most satis- 
 factory from the maintenance standpoint. 
 
 POWER SWITCHBOARD 
 
 The power switchboard most frequently furnished (Fig. 
 20) is arranged to control the charging of one set of storage 
 batteries from an engine driven generator, and in conjunction 
 with the operating board to control the power delivered to the 
 interlocking machine. 
 
 It may be placed in any accessible position in the power 
 house, convenience in making the runs of electrical conductors 
 between the power board, the charging apparatus and the 
 battery being considered. 
 
 The size and arrangement of the power board for different 
 installations is determined by the method of charging the 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 41 
 
 batteries, the number of sets and voltage of each battery, and 
 whether or not the board is to control any electric lighting 
 which may be installed at the plant. If a motor generator 
 set is to be controlled an additional panel for its starting device 
 can be mounted on the switchboard frame. 
 
 When the track circuits in the plant are operated from 
 
 FIG. 20. 
 
 STANDARD POWER SWITCHBOARD FOR ONE GENERATOR 
 AND ONE 110 VOLT BATTERY 
 
 storage batteries or from transformers located in the interlocking 
 station, it is customary to serve these track circuits through 
 switches on the power board. 
 
 On the switchboard shown in Fig. 20 are mounted a 
 no-voltage, reverse-current circuit breaker, a field rheostat, a 
 voltmeter, an ammeter, suitable switches, and the necessary 
 fuses. 
 
 The no-voltage, reverse-current circuit breaker, which is placed 
 in the charging circuit between the generator and battery, is 
 designed to open in case the voltage of the generator falls below 
 that of the battery. By means of this arrangement the charging 
 
42 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 of the battery can be accomplished without the constant atten- 
 tion of the maintainer, this permitting inspections to be made 
 at such intervals as may be most convenient. 
 
 FIG. 21. POWER AND DISTRIBUTING SWITCHBOARDS AND MOTOR 
 
 GENERATOR SETS. LAKE STREET INTERLOCKING PLANT, 
 
 CHICAGO TERMINAL, C. & N. W. R'Y 
 
 The rheostat connected in series with the generator field 
 permits the generator voltage to be accurately regulated. 
 
 The voltmeter and ammeter are arranged to give readings on 
 the charging or discharging circuits as desired. 
 
 The simplified diagram (Fig. 22) shows the principles of 
 the circuits used in connection with this board and clearly 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 43 
 
 POWER SWITCH BOARD 
 
 FIG. 22. SIMPLIFIED CIRCUITS FOR POWER SWITCHBOARD 
 
 FIG. 23. OPERATING ROOM AT OREGON SLOUGH 
 
 DRAW BRIDGE. N. P. R'Y 
 Combination power and operating switchboard at extreme left. 
 
44 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 24 FIG. 25 
 
 STANDARD OPERATING SWITCHBOARD 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 45 
 
 illustrates the functions of the various devices essential to the 
 power control. 
 
 OPERATING SWITCHBOARD 
 
 The operating switchboard shown in Figs. 24 and 25 is 
 typical of those furnished where all functions in the plant are 
 to be controlled through a single circuit breaker. When the 
 plant is sectionalized the board must be equipped with addi- 
 tional circuit breakers, one being required for each section. 
 
 The apparatus mounted on the ooard illustrated consists 
 of the cross protection circuit breaker with its indicating red 
 lamp, a polarized relay, a ground lamp and switch, a volt- 
 meter and an ammeter. A panel for lighting switches can be 
 bolted to the switchboard frame when it is desired to control 
 the lighting from this point. 
 
 FROM POWER 
 
 FROM POWER 
 BOARD 
 
 qpERATmG SWITCH JtoARp 
 CIRCUIT BREAKER 
 
 i: 
 
 POLARIZED 
 
 L. 
 FIG. 26. 
 
 INTERLOCKING MACHINE 
 
 POSITIVE Buss 
 
 Trio. Buss 
 
 POLARIZED RELAY CONTACTS 
 
 SIMPLIFIED CIRCUITS FOR OPERATING SWITCHBOARD 
 
 Lettering of the cross protection circuit breaker contacts corresponds 
 with the lettering used in Figs. 64 and 66. 
 
 The dross protection circuit breaker, introduced into the 
 power mains leading to the interlocking machine, is so controlled 
 that in the event of current being improperly applied to the 
 circuit of any function at rest, the circuit breaker will open 
 and cut all power off from the system. The red lamp is 
 arranged to be lighted at this time to call the leverman's atten- 
 tion to the fact that the circuit breaker has opened. 
 
 The design of the circuit breaker and its cover is such that 
 it cannot be prevented from opening should a 'cross occur, 
 nor can it be restored to its operating position except by means 
 of the restoring handle. 
 
 The simplified circuit (Fig. 26), in which is included only 
 the apparatus essential to the circuit breaker control, shows 
 the retaining magnet of the circuit breaker controlled through 
 the polarized relay on the switchboard and those on the inter- 
 locking machine in such a manner, that, should any of them 
 reverse their position, the circuit breaker will immediately open. 
 
46 GENERAL RAILWAY SIGNAL COMPANY 
 
 The polarized relay on the switchboard is to guard against 
 the effects of an accidental cross between the positive and 
 indication buss bars on the interlocking machine, the relay 
 operating in the same manner as the polarized relays which 
 protect the various switch and signal functions. 
 
 By means of the ground lamp and switch, the plant may be 
 tested for positive and negative grounds. 
 
 The voltmeter indicates the battery voltage at the terminals 
 of the interlocking machine. 
 
 The ammeter shows the current taken by the various func- 
 tions when they are being operated. By observing this current 
 reading the operating conditions of each function can be 
 determined. This is particularly true of the switch functions, 
 the need of oiling or adjustment being readily detected from 
 the abnormal amount of current or length of time required for 
 their operation. 
 
ELECTRIC INTERLOCKING MACHINES 
 INTERLOCKING MACHINE CONTROL 
 
 THE interlocking machine used with the G. R. S. system 
 controls the movement of switch and signal functions 
 through the medium of suitably interlocked levers, which 
 with their guides, indication magnets and circuit controllers, 
 are mounted in the common frame as shown in Fig. 27. 
 General practice is to furnish an individual lever for each signal 
 
 LAMP CASE 
 
 (CATION 
 [SELECTOR 
 
 IND. MAGNET 
 
 SAFFTY MAGNET 
 
 LOCKING PLATES 
 
 FlG. 27. 
 
 CROSS SECTION OP MODEL 2 UNIT LEVER TYPE 
 INTERLOCKING MACHINE 
 
 arm and for each switch function, except where two switches 
 are to be operated together, in which case their levers are rigidly 
 connected and operated as a unit. 
 
 The design of the machine and the controlling circuits is 
 such that the following features essential to safe operation are 
 afforded : 
 
 First No lever can be moved from a given position if any 
 other lever, mechanically interlocked therewith, is in such a 
 
48 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 position that its controlled function will conflict with the 
 function to be moved. Furthermore, due to the mechanical 
 locking being of the preliminary type, before the given lever 
 can be moved from its position, all these conflicting levers 
 will be locked against movement until such time as it is proper 
 for them to be released. 
 
 yj 
 
 FIG. 28. FOUR HUNDRED LEVER INTERLOCKING MACHINE, MODEL 2 
 
 UNIT LEVER TYPE. GRAND CENTRAL TERMINAL, TOWER "A," 
 
 N. Y. C. & H. R. R. R. 
 
 Second The full movement of any switch lever cannot be 
 completed until the controlled function has moved to, and been 
 locked in, the position corresponding with that of the lever. 
 In the case of a signal lever this correspondence of position is 
 required only on the normal movement of the lever, which 
 can be completed only after the signal arm has assumed 
 the stop position. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 49 
 
 Third Each function when in a position of rest is pro- 
 tected against any unauthorized operation which might other- 
 wise be accomplished through current being wrongfully 
 applied to its controlling circuits. 
 
 In explaining the operation of the lever, its movement is 
 considered as being divided into three parts, the prelimi- 
 nary, intermediate and final. In order that the reader may 
 not be confused on account of the lever operation having 
 previously been described as being performed in two move- 
 ments (page 18), it is desired to point out that the pre- 
 
 FIG. 29. MODEL 2 UNIT LEVER TYPE INTERLOCKING MACHINE. COLLIN- 
 WOOD INTERLOCKING PLANT, L. S. & M. S. R'Y. (See Fig. 32) 
 
 liminary and intermediate part usually constitute one contin- 
 uous movement, it being necessary to separate them, however, 
 when considering the detail operation of the lever. 
 
 The following description is based on the operation of the 
 switch lever. Each of these levers is provided with a cam 
 slot, by means of which intermittent motion is transmitted to 
 its respective tappet bar and thence to the cross locking. In 
 Fig. 30 the dotted circles 1 to 5 in the cam slot indicate the 
 positions of the locking tappet roller which correspond with 
 the like numbered position of contact block Z. In the pre- 
 liminary movement of the lever from position 1 to 2, the 
 locking tappet is moved through one-half of its stroke, 
 this movement locking all levers which conflict with the new 
 
50 GENERAL RAILWAY SIGNAL COMPANY 
 
 position of the lever in question ; in this movement no change 
 whatsoever is made in the operating circuits. During the 
 intermediate part of the travel from positions 2 to 4, the tappet 
 bar remains stationary and the contact block Z is moved out of 
 engagement with springs YY and into contact with springs 
 XX as shown in Fig. 31, this setting up the circuits for the 
 operation of the function. The lever is held at this point, 
 (position 4), through the mechanical design of the lever proper, 
 until such time as the function having moved to a correspond- 
 ing position, generates the dynamic indication current which 
 effects the release of the lever and permits its movement to 
 position 5. During this final movement from position 4 to 5, 
 the stroke of the locking tappet is completed, thereby unlocking 
 all levers which do not conflict with the new position of the 
 operated lever. 
 
 The method by which the lever is prevented from completing 
 its stroke, until the controlled function has moved to a corre- 
 sponding position and has sent in its indication, is illustrated 
 by the following : in moving from positions 1 to 2 projection M 
 on the lever coming against projection K on latch L, causes 
 the latch to assume the position shown in Fig. 31. This 
 brings projection J on latch L into the path of tooth Q on the 
 lever. In moving from position 2 to 4, tooth Q engages with 
 cam N, rotating it to the position shown in Fig. 31. As it 
 passes the central position (shown dotted in Fig. 31) it comes 
 in contact with dog P which is forced under latch L, thereby 
 locking the latch L in the position assumed. The lever is 
 stopped at position 4 by tooth Q coming against projection J 
 on latch L as previously explained. The indication current, 
 by flowing through magnet I, lifts armature T which causes 
 plunger R to strike dog P and trip it out from under latch L. 
 The latch L then drops to the position shown in Fig. 30, 
 thereby releasing the lever and permitting its final movement 
 to be accomplished. 
 
 The movement of the lever from reverse to normal is per- 
 formed in a similar manner to that described above. Atten- 
 tion is called to the fact that once the lever has been moved to, 
 or beyond, position 3, it can neither be moved forward beyond 
 position 4 nor back beyond position 2 without the receipt of 
 an indication. 
 
 The movement of the signal lever is identical with 
 that of the switch lever except that no electrical indi- 
 cation is required during the reverse movement, the lever not 
 being checked at position 4 due to a change in the design 
 of dog P, which is mechanically tripped at this point from 
 under latch L by cam N. The mechanical locking insures that 
 before a signal can be given for any route, that all switch and 
 derail functions in the route are thrown to the proper posi- 
 tions and locked in that position, and that all opposing signals 
 are in the stop position. No changes can be made in the 
 position of any of these functions until the lever, controlling 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 51 
 
52 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 53 
 
 the signal displayed at proceed, has been replaced to its full 
 normal position. 
 
 The various functions are protected against unauthorized 
 movement by means of the cross protection system, as de- 
 scribed on page 89, the individual polarized relays which 
 furnish this protection being mounted on the terminal board 
 of the interlocking machine. All lever contacts which form a 
 part of this cross protection scheme are used in the operation 
 of the function, and hence are checked as to their integrity 
 with every complete operation. 
 
 MODEL 2 UNIT LEVER TYPE INTERLOCKING MACHINE 
 
 The description of the interlocking machine following is based 
 on the Model 2 Unit Lever Type (Fig. 27) which is considered 
 the standard machine. This machine is a development of the 
 Model 2, still widely used, a cross section of this being illus- 
 trated by Fig. 137. Modifications of the Unit Lever Type 
 machine are shown by Figs. 32 and 138, the latter being 
 furnished when more contacts are required for supplementary 
 circuits than can be secured on the regular lever circuit con- 
 troller. 
 
 The standard machine essentially comprises the frame, the 
 levers with their guides, indication magnets and circuit con- 
 trollers, the locking plates and locking, the terminal board, 
 and the machine cabinet. 
 
 Frame. 
 
 The frame work, which consists of a bed, supporting legs 
 and brackets, is substantially constructed, thereby insuring 
 that all inter-related mechanical parts are maintained in their 
 proper relative positions. For machines having a capacity up 
 to forty-eight lever spaces, the bed is cast in one unit. Machines 
 of over forty-eight levers are made up of various combinations 
 of beds bolted together to give the required lever spaces. 
 
 Locking Plates and Locking. 
 
 The locking plates are securely attached to the front of the 
 machine frame, being furnished in tiers to a maximum of 
 three, the number depending upon the amount of locking 
 required at each individual plant. A fourth tier can be 
 furnished when necessary by using a special form of leg, 
 which has sufficient height to accommodate the extra tier of 
 plates. 
 
 The locking plates are designed with vertical and horizontal 
 slots, the locking tappets, one of which is attached to each 
 lever, being fitted in the vertical slot directly beneath its 
 respective lever. Movement is transmitted from ^the lever 
 through the medium of the tappets to the cross locking, which 
 slides back and forth in the horizontal slots of the locking 
 plates. The dogs used in the cross locking can be furnished 
 screwed or riveted to the locking strips, as desired. 
 
54 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
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ELECTRIC INTERLOCKING HANDBOOK 
 
 55 
 
56 GENERAL RAILWAY SIGNAL COMPANY 
 
 Each tier of locking has eight of these horizontal slots, 
 and each of these slots is capable of accommodating four 
 locking strips, thus giving this type of locking bed a large 
 capacity as is indicated by the fact that the locking required 
 for extremely large and complicated layouts has been readily 
 accommodated in three tiers. In fact, it is a very rare 
 occurrence that the fourth tier is ever required. 
 
 By using locking of the vertical type no additional floor 
 space is required beyond that ordinarily taken by the machine, 
 
 FIG. 35. UNIT TYPE SWITCH LEVER EQUIPPED 
 
 WITH LEVER LOCK AND LAMP CASE 
 
 (See Fig. 141.) 
 
 no matter how many tiers are provided. This type of locking 
 also permits ready access for inspection or cleaning, or making 
 any changes which may be required. 
 
 Levers. 
 
 Each lever with its guide, indication magnet, controllers, 
 etc., comprises a complete unit in the interlocking machine, 
 the design being such that the unit may be removed or replaced 
 in the machine without moving the lever tappet from the 
 normal position or disturbing adjacent levers in any way. The 
 lever guide is jointly supported by the top edge of the locking 
 plates and a longitudinal bar fastened to the brackets, the 
 
ELECTRIC INTERLOCKING HANDBOOK 57 
 
 circuit controllers being screwed to two other bars which are 
 supported by this same bracket. 
 
 The circuit controller with which each lever is equipped can 
 be provided with a maximum of five tiers of contacts, con- 
 trolling five normal and five reverse independent circuits, which 
 affords more contacts than are ordinarily desired for supple- 
 mentary circuits. 
 
 The space required for each unit is but two inches, this 
 permitting the complete machine to occupy less space length- 
 wise than other existing types of interlocking machines, either 
 power or mechanical, having the same lever capacity. 
 
 Lamp Case and Number Plate. 
 
 The combined lamp case and number plate is mounted above 
 each lever, its base being attached to a plate screwed to the top 
 of the lever guide, and its top to the cabinet frame. The num- 
 ber plate is designed to lie at an angle which renders it readily 
 visible to the operator when manipulating the levers. Bulbs 
 and sockets are furnished only for such levers as may be 
 specified, generally being used in conjunction with some type 
 of electric locking to give an indication as to whether the lever 
 may be moved or not. If desired, a double lamp case can be 
 furnished to give two separate indications. 
 
 Terminal Board. 
 
 The slate terminal board is securely attached to the brackets 
 on the rear of the machine On this board are mounted the 
 switch and signal buss bars, the individual polarized relays, 
 fuses for the operating circuits, and the terminal posts for all 
 wires which form a part of any of the interlocking machine 
 circuits. The wires running from the binding posts to the 
 various contacts, etc., in the machine are made up as formed 
 leads, thus presenting a neat and uniform appearance ; it also 
 simplifies any "connecting up " incidental to the field installa- 
 tion of additional levers to the machine. 
 
 All fuses and terminal posts on the board are located directly 
 beneath their respective levers, the terminal posts being 
 lettered in correspondence with the circuit plan to indicate 
 the wires which are to be attached to each post. 
 
 Polarized Relay. 
 
 The polarized relay which is illustrated by Fig. 36 is 
 mounted on the terminal board directly beneath its lever. 
 It is provided with a soft iron core which lies lengthwise between 
 the poles of a permanent magnet, the design being such that 
 current passing in one direction through a winding on the 
 soft iron core, tends to hold the relay armature normal and 
 contact closed, while current in the opposite direction imme- 
 diately reverses the armature and thereby causes the contact 
 to open. An extension of the armature is provided for con- 
 
58 GENERAL RAILWAY SIGNAL COMPANY 
 
 venience in replacing it to the normal position should it for 
 any cause be reversed 
 
 Indication Selectors. 
 
 The indication selectors, one of which is used in connec- 
 tion with each switch function, are mounted on a shelf sup- 
 ported by a bracket on the rear of the interlocking machine. 
 The selector is simple in design, consisting of two electro 
 magnets and a contacting armature which throws in one 
 direction when the lever is reversed and in the other when the 
 lever is put normal. 
 
 FIG. 36. POLARIZED RELAY 
 
 INTERLOCKING MACHINE ACCESSORIES 
 Lever Locks. 
 
 The electric lever lock, illustrated by Fig. 35, may be 
 applied to any lever in the machine, its winding being designed 
 for operation on direct or alternating current. The lock is 
 designed to be mounted on the top of the lever guide, locking 
 the lever in any required position by means of a solenoid 
 plunger, which, when the lock is de-energized, drops into a 
 notch cut on the top of the lever. These notches may be 
 arranged so that the lever will be locked in any position as 
 required by the electric locking circuits used at the plant. 
 The circuit for the lock coil is broken through a contact spring 
 actuated by the lever latch, the lock therefore not consuming 
 energy except when lever is to be moved. 
 
 Mechanical Time Release. 
 
 The mechanical time release furnished with the G. R. S. 
 interlocking is illustrated by Fig. 37, and the method of its 
 application to the machine by Fig. 38. It is used in connec- 
 tion with electric locking circuits to effect the release of a 
 route in case of emergency, this being accomplished by manipu- 
 lating the release to its full reverse position, at which point a 
 contact is closed to pick up a stick relay, energize a lever lock, 
 etc. The first movement of the device towards the reverse 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 59 
 
 position, however, mechanically locks, in their given positions 
 the levers controlling all functions in the route, this necessitat- 
 ing that the release be returned to its normal position before 
 the route can be changed. The operation of the please to the 
 reverse position and back to the normal position affords a 
 time interval of about two minutes. 
 
 FIG. 37 
 MECHANICAL TIME RELEASE 
 
SWITCH OPERATING MECHANISMS 
 SWITCH MACHINE CONTROL 
 
 SWITCH and derail functions in the G. R. S. system are 
 operated by switch and lock movements, driven by series 
 wound direct current motors. 
 
 These switch mechanisms, each of which is under the con- 
 trol of a lever in the interlocking machine, require for their 
 operation two wires only, one being used for the normal 
 and the other for the reverse operation. These same wires 
 are used for indicating purposes, the normal control wire being 
 used for the reverse indication and the reverse control for the 
 normal indication. The circuit is connected to main common 
 at the switch location. 
 
 When the lever is moved to a position to cause the operation 
 of the switch mechanism (see dotted position of lever con- 
 tacts in Fig. 39), current is taken from the positive buss 
 bar through the safety magnet, indication selector, lever 
 contacts and the control wire, through the switch motor 
 and to common. This causes the desired movement of 
 the switch machine, which performs the following functions in 
 the order given : 
 
 First The detector bar is raised and the switch unlocked, 
 
 Second The switch points thrown, 
 
 Third The switch points locked and the bar lowered, 
 
 Fourth and Lastly Current is cut off from the motor, and 
 the terminals of the motor armature reversed for indication 
 purposes, this leaving the motor properly connected for the 
 next movement. 
 
 The motor is now on a closed circuit which includes the 
 indication magnet. Due to the momentum acquired during 
 the switch operation, the motor armature continues on several 
 revolutions for the generation of the momentary current 
 which energizes the indication magnet and thereby permits 
 the final movement of the lever to be completed. 
 
 The operation of the switch machine in the opposite direc- 
 tion is accomplished in the same manner as described above. 
 
 The changing of the motor connections at the end of the 
 switch operation is effected by the mechanical shifting of the 
 contact block in the pole changer (Figs. 42 and 46). In 
 addition to being mechanically operated, this contact block is 
 under the control of two sets of solenoid magnets, so that 
 should the switch fail to complete its movement the controlling 
 lever may be shifted, and, through the energizing of one 
 set of the magnets, cause the pole changer to set up the circuit 
 for the operation of the switch in the opposite direction. 
 This places the mechanism so under the control of the lever- 
 man that should the switch points be blocked with snow, ice, 
 etc., the points may be worked back and forth, frequently 
 dislodging the obstruction, thereby permitting the desired 
 movement of the switch to be completed. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 61 
 
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62 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 indication magnet with the indication magnet armature resting 
 on its poles, some distance from the poles of the indication 
 magnet. The safety magnet coils are so connected in the 
 operating circuit that the whole operating current flows 
 through them, hence any current flowing through the indica- 
 tion magnet, due to a cross between the control wires of the 
 function, cannot exceed the current through the safety magnet. 
 The winding of the safety magnet is proportioned so that in 
 conjunction with the above two features, the indication mag- 
 net armature cannot be lifted by current resulting from a 
 cross as stated above. 
 
 FIG. 40. 
 
 MODEL 2 SWITCH MACHINE. BUFFALO CREEK INTER- 
 LOCKING PLANT, L. S. & M. S. R'Y 
 
 From the time when the lever is moved to the new operating 
 position until the movement of the switch machine is com- 
 pleted, the indication selector further insures against the pos- 
 sible receipt of any improper indication, being so connected 
 that the operating current will attract its armature and close 
 the contact for the reverse indication only when the lever is 
 moved reverse, and the contact for the normal indication 
 when the lever is moved normal. It should be noted that 
 both the indication selector and safety magnet coils are con- 
 nected in series with the control circuit, therefore if the cir- 
 cuit through them is not intact, operation of the function will 
 be prevented. 
 
 When the motor operating circuit is opened by the action 
 of the pole changer, after the switch has been locked in posi- 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 63 
 
 tion, current ceases to flow through the safety magnet. There- 
 fore the armature of the indication magnet is no longer held 
 down, this permitting the indication to be effected upon 
 receipt of the dynamic current generated by the motor. 
 
 The mechanism is now at rest protected against any unau- 
 thorized movement in the same manner as before the con- 
 trolling lever was reversed. 
 
 Owing to the design of the operating circuits, the magnetic 
 
 FIG. 41. MODEL 2 SWITCH MACHINE. CLINTON STREET INTERLOCKING 
 
 PLANT, CHICAGO TERMINAL, C. & N. W. R'Y 
 
 Spring attachment shown is furnished with Model 2 switch machine 
 when detector bar is not installed. 
 
 control of the pole changer prevents the switch from being 
 moved by hand from the position occupied, except through 
 breaking the operating circuits by some such means as re- 
 moving the motor brushes. If this is done and the machine 
 moved to a position not corresponding with that of its con- 
 trolling lever, upon the replacement of the brushes, the switch 
 will immediately assume its proper position. Manipulation 
 of the pole changer by hand will not cause movement of the 
 switch out of correspondence with its lever. 
 
64 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 MODEL 2 SWITCH MACHINE 
 
 The Model 2 switch machine, illustrated by Fig. 43, con- 
 sists of the motor, gearing, lock movement and the pole changer 
 with its actuating movement. The gear frame and locking 
 movement are securely bolted to a tie plate as shown, to 
 which plate the stock rails are also securely attached, thus 
 rigidly maintaining all parts of the switch machine in their 
 proper relation to each other and to the rail. 
 
 Movement is transmitted to the various switch parts by the 
 motor through a train of spur gears. 
 
 FIG. 42. POLE CHANGER FOR MODEL 2 SWITCH MACHINE 
 
 The locking plunger I and detector bar are actuated through 
 the lock crank H and the driving rod G, this latter being 
 directly connected to the stud F on the main gear D 1 . It will 
 be seen that a train occupying the track, in preventing the 
 initial movement of the detector bar, would make impossible 
 the withdrawal of the lock plunger from the throw and lock 
 rods, and therefore prevent any movement of the switch 
 points. 
 
 The switch points are thrown by the rod J and the cam 
 crank E due to the stud F on the main gear engaging with the 
 cam crank. 
 
 The operation of the pole changer B is effected through the 
 medium of the pole changer movement L by the last one- 
 eighth inch movement of the lock plunger I after it has passed 
 through the lock rod K (Fig. 146). 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 65 
 
 M N 
 
 DETECTOR BAR 
 CONNECTION 
 
 FIG. 43. MODEL 2 SWITCH MACHINE 
 
 Motor 
 
 Pole Changer 
 Friction Clutch 
 Main Gear 
 Intermediate Gear 
 Cam Crank 
 Stud on Main Gear 
 Driving Rod 
 
 H Lock Crank 
 
 I Lock Plunger 
 
 J Throw Rod 
 
 K Lock Rod 
 
 L Pole Changer Movement 
 
 M Pole Changer Connecting Rod 
 
 JV Detector Bar Driving Link 
 
 O Pin 
 
66 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
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ELECTRIC INTERLOCKING HANDBOOK 67 
 
 The design of the mechanism is such as to allow the switch 
 motor A, due to its acquired momentum, to continue its rota- 
 tion for the generation of the indication, which checks the 
 speed of the motor and brings it to rest without shock. 
 
 A friction clutch C is introduced into the connection between 
 the switch motor and the main gear to relieve the switch 
 mechanism from any injurious strain should it suddenly be 
 brought to stop by an obstruction in the switch points. 
 
 MODEL 4 SWITCH MACHINE 
 
 The Model 4 switch machine shown in Fig. 44, is designed 
 with all operating parts within one case, and is especially 
 adapted for installation where clearances are limited. The 
 
 FIG. 45. MODEL 4 SWITCH MACHINE. NOBLE STREET INTERLOCKING 
 PLANT, CHICAGO TERMINAL, C. & N. W. R'r 
 
 case, which affords complete protection against the weather, 
 provides a base plate for the mechanism, being bolted through 
 the tie plate to the head block and the next tie back (Fig. 149). 
 The operating parts consist of the motor A, a train of spur 
 gears, the main or cam gear D, the pole changer M, the throw 
 rod J and locking bar F. 
 
 The motor through the medium of the train of gears drives 
 the cam gear, from which gear the various parts of the switch 
 machine are operated. 
 
 The intermittent movement of the locking bar and detector 
 bar is accomplished by the engagement of rollers on the locking 
 bar with the cam slot on the upper side of the main gear. 
 Staggered locking is provided by the arrangement of the dogs 
 on the locking bar, these dogs being placed so that after one 
 dog has been withdrawn to release the lock rod, the switch 
 points must be moved to the opposite position before the other 
 dog can enter its slot in the lock rod. The throw rod is locked 
 
68 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 in both extreme positions of the switch by a bolt operated 
 from the cam movement. 
 
 The switch points are thrown at the proper time by a roller 
 on the lower side of the main gear engaging a jaw in the 
 throw rod. 
 
 The principles of the pole changer movement are essen- 
 tially the same as in the Model 2 switch machine, although the 
 mechanical method of effecting this action is accomplished 
 through the main gear movement and locking bar, instead of 
 
 FIG. 46. POLE CHANGER FOB MODEL 4 SWITCH MACHINE 
 Tripper arm N shown at the top of its vertical movement. 
 
 through the pole changer movement and locking plunger as in 
 the Model 2. Contact blocks Si and S 2 are operated from tripper 
 arm N which engages at the proper time with a cam either on the 
 or lower surface of the main gear D, depending 
 
 upper 
 
 direction of travel of the mechanism. 
 
 on the 
 
 The tripper arm is 
 placed in a position to engage with the proper cam only after 
 the switch has been locked in position at the end of its move- 
 ment. This is accomplished through the medium of cranks 
 Tj and T 2 , a roller U on the latter working in a cam slot on the 
 locking rod P 4 . The contact arm V (which corresponds with 
 the commutator T on the Model 2 pole changer, Fig. 42) is 
 operated by this same crank movement. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 69 
 
 The cam gear is designed to permit a free run of the motor 
 at the end of the operation of the mechanism for the purpose 
 of generating a strong and positive indication current. 
 
 A friction clutch, designed with large surfaces and lined with 
 fibre, is provided to protect the mechanism from shock, should 
 its movements be obstructed. 
 
 A switch circuit controller can be furnished if desired, 
 located within the mechanism case at the point indicated by 
 letter O. The operating part consists of a frame carrying 
 contact fingers and a cylindrical commutator W upon which 
 are mounted contact segments. As the switch is unlocked, a 
 disengaging arm X with roller Y working in a cam slot on the 
 locking bar F lf lowers the commutator out of engagement with 
 the contact springs. During the movement of the switch 
 points, the commutator is rotated on its axis through motion 
 
 FIG. 47. SWITCH CIRCUIT CONTROLLER FOR MODEL 4 SWITCH MACHINE 
 
 transmitted from the switch points by means of a crank con- 
 nection, a sector (not shown) and pinions Z t and Z 2 . After 
 the points are locked in position the commutator is raised into 
 engagement with the contact fingers by the engaging arm and 
 cam slot movement. It will be seen that this control insures 
 the switch points are in position and locked in position before 
 the switch circuit controller can be closed. The maximum 
 capacity of the controller is ten independent circuits, the con- 
 tacts being adjustable in pairs to close as desired at the 
 normal or reverse positions of the switch. 
 
 The switch mechanism can be used right or left handed 
 without change, as the lock and throw rods may be connected 
 from either side. A double locking cage is furnished when the 
 machine is to operate a double slip switch or movable point 
 frog, thus avoiding the necessity of using a plunger lock with its 
 special connections otherwise required for the second lock rod. 
 
 All parts are assembled in the factory and tested before 
 shipment under conditions approximating as nearly as possible 
 the service to be given the machine after installation. 
 
MOTOR DRIVEN SIGNAL MECHANISMS 
 
 MOTOR driven signals in the G. R. S. system of electric 
 interlocking are operated by mechanisms in which a 
 series wound motor is directly connected to the sema- 
 phore shaft through the medium of low reduction gearing. No 
 dash-pot or electro-mechanical slot is required for this type of 
 signal. The mechanism is applicable for use as a high or 
 dwarf signal. 
 
 The mechanisms furnished are of two types : 
 
 First, the non-automatic, which is entirely under the control 
 of a lever in the interlocking machine. Generally speaking, 
 this type is furnished for dwarf signals, and for such high 
 signals as will at no time require track circuit control. 
 
 Second, the semi-automatic, which is operated under the 
 joint control of a lever in the interlocking machine and the 
 track circuits in such sections of track as are governed by the 
 signal arm. The semi-automatic mechanism is also furnished 
 for non-automatic high signals when there is a possibility of 
 the signal arm being controlled by track circuits at some future 
 time, or in case it is desired to have uniformity in the type of 
 mechanism throughout the installation. 
 
 Either of the above types can be adapted for operation in 
 two or three positions, upper or lower quadrant, and to give 
 right or left hand indications as desired. 
 
 In the two position non-automatic signals, but one wire 
 besides the main common is required for its control, this wire 
 being used both for operating and indicating purposes. When 
 the signal is to operate in three positions an additional control 
 wire is required. In the case of semi-automatic control, an 
 additional wire may or may not be required, depending entirely 
 upon the arrangement of the track circuits in the route governed 
 by the signal arm. 
 
 NON-AUTOMATIC SIGNAL CONTROL 
 
 The following description of the signal operation is based 
 on the circuit shown in Fig. 48 which is for the control of the 
 two position non-automatic signal mechanism. 
 
 Upon reversal of the controlling lever current is taken 
 from the positive buss bar through the lever contacts, the 
 control wire, the operating field and armature of the signal 
 motor, and thence to common through the various switch 
 circuit controllers as required. This causes the movement of 
 the blade from stop to the proceed position, upon the com- 
 pletion of which movement circuit breaker contact B opens 
 and A closes, this connecting the holding field of the motor in 
 series with the operating field and armature. The design of 
 the pole pieces on which the holding field windings are mounted, 
 is such that the magnetic flux, thrown across the air gap 
 between the motor armature and the pole pieces, magnetically 
 locks the armature against rotation and thereby retains the 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 71 
 
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72 GENERAL RAILWAY SIGNAL COMPANY 
 
 mechanism and brings it to rest without shock to any of its 
 parts. 
 
 In the case of the three position signal, operation from the 
 zero degree position to the forty-five degree position is the 
 same as described above. Operation from this point on to the 
 ninety degree position is ordinarily dependent upon the signal 
 in advance, it being necessary however that the controlling 
 lever be reversed before movement of the mechanism can take 
 place. The mechanism is held in its ninety degree position 
 through the medium of the holding fields in the same manner as 
 in the forty-five degree position. When the signal arm is re- 
 turning from the ninety degree position and is to be held at 
 the forty-five degree position, its movement is arrested at that 
 point by short circuiting a " snubbing " winding on the motor 
 (winding and contact not shown in Fig. 48), which causes a 
 momentary current to flow in this winding, thereby bringing 
 the mechanism parts to rest. The semaphore arm is retained 
 in this position by current flowing through the retaining fields 
 of the motor, as previously explained. 
 
 SEMI-AUTOMATIC SIGNAL CONTROL 
 
 When it is desired to have the signal controlled semi-auto- 
 matically, the operation differs from that described above 
 in that the first forty degree movement of the mechanism 
 from the normal position does not affect the position of the 
 signal arm, but puts under tension a set of coil springs which 
 are strong enough to rotate the motor on the return movement 
 with sufficient speed to generate the current for energizing 
 the indication magnet on the lever. This preliminary move- 
 ment of the mechanism is always under the control of the 
 operating lever irrespective of whether the track circuit is 
 occupied or not, the receipt of the indication therefore ^ot 
 requiring the restoration of the lever to the normal position 
 simultaneous with the entrance of a train into the controlling 
 track section. Any movement of the mechanism beyond this 
 point, however, is dependent upon the track circuit being 
 unoccupied. 
 
 Referring to the circuit for the two position semi-auto- 
 matic signal as shown in Fig. 49, it will be seen that upon 
 reversal of the controlling lever current is taken from the 
 positive buss bar through the lever contacts, the control 
 wire, the signal motor operating field and armature and thence 
 to common. This causes the operation of the mechanism 
 through its preliminary forty degree movement to the 
 zero degree position, at which point the mechanism will 
 be held against the tension of the coil springs, in the event 
 of the track circuit being occupied; this is accomplished by 
 circuit breaker contact B x opening and A! closing which 
 connects the holding fields in series with the operating fields 
 and armature of the signal motor. Should the track circuit 
 be unoccupied, the mechanism will not stop at this point but 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 73 
 
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 GENERAL RAILWAY SIGNAL COMPANY 
 
 time as its lever may be reversed ; the control is so arranged that 
 a second clearing of the signal arm can be secured only after the 
 mechanism has been returned to its minus forty (40) degree 
 position. When the lever is restored normal, energy is cut off 
 from the motor and the mechanism, due to the tension of 
 the coil springs, is driven to its minus forty ( 40) degree 
 position; just before reaching this position circuit breaker 
 
 FIG. 50. MODEL 2A DWARF SIGNAL. ELECTRIC DIVISION, 
 N. Y. C. & H. R. R. R. 
 
 contact B! closes, thus connecting the motor armature and 
 operating field in their original closed circuit in which is 
 included the indication magnet. Due to the momentum of 
 the motor armature acquired during this movement, the motor 
 (now a generator) builds up the momentary dynamic current 
 necessary to energize the indication magnet and release the 
 lever, thereby permitting it to be restored to its full normal 
 position. 
 
 Should the controlling lever be placed normal before the 
 the controlling track section, the signal 
 
 entrance of a train into 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 75 
 
 arm and mechanism returns to the zero 
 position, and the mechanism continues its 
 
 degree or stop 
 rotation to the 
 
 minus forty (40) degree position due to the action of the 
 indication springs; when within a few degrees of the end oHts 
 travel, the dynamic indication for the release of the controlling 
 lever is generated as described above. 
 
 FIG. 
 
 DEL 2A DWARF SIGNALS. 
 C. & N. W. R'Y 
 
 CHICAGO TERMINAL, 
 
 It will be seen that the operation of the signal mechanism 
 proper, from the time the signal blade begins its movement 
 toward the proceed position until its return to the stop posi- 
 tion, is the same as that of the non-automatic signal, the 
 indication springs being in no way depended upon to bring the 
 signal arm to the stop position. This same statement applies 
 also to three position operation of the semi-automatic 
 mechanism. 
 
76 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 a -o^gfcg 
 
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ELECTRIC INTERLOCKING HANDBOOK 77 
 
 MODEL 2A NON-AUTOMATIC SIGNAL MECHANISM 
 
 The non-automatic signal mechanism (Fig. 52) consists 
 essentially of three main parts, the motor, a train of gears 
 and the circuit breaker. These are all housed in a weather 
 proof case, which is provided with doors to give convenient 
 access to all parts. 
 
 When the mechanism is used for the operation of high 
 signals, it is fastened to a clamp bearing (Fig. 54) which 
 carries the semaphore shaft S, the design of this bearing 
 permitting the mechanism to be supported at any desired 
 height on the signal mast and at any angle to the track. The 
 bearing is equipped with a spring stop P, which besides acting 
 as a buffer permits the close adjustment of the signal blade in 
 its stop position. A universal coupling L 1; L,, L 3 introduced 
 between the driving shaft J and semaphore shaft S, lends 
 itself to a simple means of locking the signal arm in the stop 
 position in such a way as to prevent improper operation of 
 the signal by any outside agency. 
 
 When the signal mechanism is to be used for the operation 
 of a dwarf signal, it is bolted to a stand (Fig. 55) carrying 
 the spectacle shaft T and provided with springs Ut and U 2 
 which are for the purpose of giving sufficient returning torque 
 to the dwarf signal arm to cause it to assume the stop position 
 when the current holding it at proceed is cut off. This is 
 necessary since the dwarf signal arm cannot be readily designed 
 to have sufficient weight so that gravity can be depended upon 
 for returning it to the stop position. The complete dwarf 
 mechanism takes up but little room which permits it to be 
 installed where clearances are limited, as is illustrated by 
 Fig. 202. 
 
 The motor A used in the signal mechanism is of the four 
 pole type, two of these poles being modified in such a man- 
 ner as to permit the motor armature to constitute the means for 
 holding the signal arm in the proceed positions. This modified 
 design consists of serrating the surfaces of these two poles, 
 so that when the holding field windings are energized, a dense 
 magnetic flux will flow across the air gap between the pole 
 pieces and the motor armature in such a manner as to pre- 
 vent rotation of the armature, and, consequently, movement 
 of the signal blade. Owing to the high resistance of these 
 windings the amount of current used for the purpose is re- 
 duced to a minimum. The ''snubbing" winding previously 
 referred to is entirely independent from the operating wind- 
 ings of the motor, its function being to check the speed of the 
 motor when it is desired to hold the signal arm in the forty- 
 five degree position. 
 
 A friction clutch is introduced between the motor A and 
 its driving pinion C to insure that no undue strain whatsoever 
 will be transmitted to the mechanism gearing. 
 
 The gearing is designed with heavy teeth and large clear- 
 ances as shown by Fig. 53, this latter insuring that the 
 
78 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 mechanisms will run freely in either direction and that no 
 ordinary obstructions such as dirt, cinders, waste, etc., will 
 interfere with its movement; only five foot pounds at the 
 semaphore shaft are required to run the mechanism back to 
 its normal position. 
 
 FIG. 53. DIAGRAM ILLUSTRATING GEARING CLEARANCE 
 
 IN MODEL 2A SIGNAL MECHANISM 
 
 Scale, full size. 
 
 The circuit breaker B is a complete unit operated from the 
 main driving shaft J by means of the segmental gears K t 
 and K 2 . It consists of a frame carrying contact fingers and 
 a revolving commutator on which are mounted contact seg- 
 ments as required. The circuit breaker has a maximum 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 79 
 
 capacity of fourteen circuits, such contacts as are used to 
 control operating and indicating circuits being arranged to 
 be quick acting, "snapping" over from one position to the 
 other at the proper predetermined time. Each contact finger 
 is provided with convenient means of adjustment, and by 
 means of a locking finger is positively protected again acci- 
 dental displacement. 
 
 V --' " -* 
 
 FIG. 54. CLAMP BEARING FOR MOUNTING MODEL 2A SIGNAL MECHAN- 
 ISM ON SIGNAL MAST 
 
 FIG. 55. DWARF BEARING FOR MODEL 2A SIGNAL MECHANISM 
 
80 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 fe 
 
ELECTRIC INTERLOCKING HANDBOOK 81 
 
 MODEL 2A SEMI-AUTOMATIC SIGNAL MECHANISM 
 
 The semi-automatic signal mechanism (Fig. 56) consists 
 essentially, as does the non-automatic mechanism, of a motor, 
 a train of gears and circuit breaker, with the addition, however, 
 of the spring attachment which is used to produce rotation of 
 the motor armature for indication purposes after the signal 
 arm has reached the stop position. These parts are enclosed 
 in a weather proof case similar in construction to that used for 
 
 Fia. 57. MODEL 2 A SEMI-AUTOMATIC SIGNAL 
 
 the non-automatic signal, the design permitting the mechanism 
 to be fastened to a clamp bearing for mounting on high signal 
 masts or used in connection with a stand for operation as a 
 dwarf. 
 
 The motor, train of gears and circuit breaker are essentially 
 the same as those described above, it being therefore only 
 necessary to touch upon the design of the indication spring 
 attachment and the universal coupling, these being the only 
 points in which this signal is radically different from the non- 
 automatic previously described. 
 
 The initial free movement of the mechanism is accomplished 
 by having one shoulder of the coupling L 2 so cut away that 
 a forty degree rotation of the driving shaft J is necessary 
 before it will engage with the semaphore shaft S, this movement 
 
82 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 as previously mentioned putting under tension the pair of coil 
 springs N a and N ? . 
 
 Fig. 58 shows diagramatically this spring attachment and the 
 manner in which the springs N\ and N 2 are put under tension ; 
 it will be noted that the two coil springs are connected to the 
 driving shaft J by means of an equalizer O and a curved link 
 
 Lost motion betrroen 
 Sector H and Spectacle 
 
 Sector operated by motor 
 through train of gears. 
 
 FIG. 58. DIAGRAM SHOWING OPERATION OF SPRING ATTACHMENT USED 
 IN MODEL 2A SEMI-AUTOMATIC SIGNAL MECHANISM 
 
 M, one end of which is fastened to the main sector H on 
 the driving shaft J. As is clearly illustrated by the various 
 positions of the device the design is such that the springs do 
 not exert any torque on the mechanism after the blade has 
 moved a few degrees from the stop position; therefore it is 
 plain that the springs are in no way depended upon for the 
 restoration of the blade to the normal position. 
 
SOLENOID DWARF SIGNAL MECHANISMS 
 
 SOLENOID dwarf signals used in the G. R. S. system are 
 designed to operate in two positions, upper or lower 
 quadrant, with a forty-five, sixty or ninety degree travel 
 of the arm. Two sets of magnet windings are provided, 
 which consist of operating coils of low resistance and holding 
 coils of high resistance. The movement of the solenoid 
 magnet plungers is transmitted by means of suitable con- 
 nection to the dwarf spectacle. 
 
 FIG. 59. MODEL 2 SOLENOID DWARF SIGNAL 
 
 DWARF SIGNAL CONTROL 
 
 Each of these mechanisms requires for its operation a con- 
 trol wire, and since it is impracticable to secure a dynamic 
 indication from a signal of the solenoid type, an additional 
 wire is required for indication purposes. The circuit is con- 
 nected to main common either at the dwarf location or 
 through contacts on switch circuit controllers when required. 
 
 Upon reversal of the controlling lever (Fig. 60), current is 
 taken from the positive buss bar through the lever contacts, 
 the control wire, and the solenoid operating coils A! and A a 
 to common. This causes movement of the signal arm from the 
 stop to the proceed position. As the arm reaches the pro- 
 ceed position, the circuit breaker contact C opens, which 
 connects the high resistance holding coils B x and B 2 in series 
 
84 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
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ELECTRIC INTERLOCKING HANDBOOK 
 
 85 
 
 which, in addition to supporting the mechanism, is designed 
 to carry the dwarf spectacle shaft. A hinged cover on the 
 top of the case gives convenient access to the mechanism. 
 
 The movement of the yoke F connecting the solenoid plung- 
 ers E x and E 2 , is transmitted through the medium of the rack 
 G and pinion H to the crank J, and thence by means of the 
 connecting rod (not shown) to the dwarf spectacle shaft. 
 
 When in the stop position the signal arm cannot be moved 
 by any outside agency, due to the crank J being "on center" 
 at that point. 
 
 FIG. 61. MODEL 2 SOLENOID DWARF SIGNAL OPERATING 
 MECHANISM 
 
 Aj-^2 Operating'Coils F Yoke 
 
 Bi-B 2 Holding Coils G Rack 
 
 C Operating Contact H Pinion 
 
 D Indicating Contact J Crank 
 Ei-E, Solenoid Plungers 
 
 The circuits for the control of the mechanism are broken 
 through pairs of springs which make contact at the proper 
 time with metal pieces, fastened to a commutator mounted 
 upon the same shaft as the pinion H. The operating contact 
 C is designed to hold its circuit closed throughout the move- 
 ment until the blade has assumed the proceed position. The 
 indicating contact D is closed only when the blade is in the 
 stop position. 
 
86 GENERAL RAILWAY SIGNAL COMPANY 
 
 MODEL 3 DWARF SIGNAL MECHANISM 
 
 The Model 3 dwarf signal mechanism (Fig. 63) consists, of 
 the solenoid magnets and an operating rod which is directly 
 connected to the dwarf spectacle shaft. This mechanism is 
 mounted in a case which is designed to carry the dwarf spec- 
 tacle shaft and is provided with a sliding cover to permit 
 ready access to the operating parts. 
 
 The operation of the mechanism is similar in principle to 
 that of the Model 2 dwarf except that the movement of the 
 
 FIG. 62. MODEL 3 SOLENOID DWARF SIGNAL 
 
 magnet plungers E t and E 2 is transmitted directly to the 
 spectacle shaft through the operating rod G, a roller H on the 
 operating rod working in an escapement crank (not shown) 
 on the semaphore shaft. The design is such that when the 
 signal is in its normal position, the arm is locked against 
 movement from the outside. 
 
 The overall dimensions of the signal are such as to allow its 
 location where the available clearances will not permit the 
 use of the Model 2 dwarf signal. 
 
 The circuit breaker contacts consist of pairs of springs 
 which are bridged by contact rollers, actuated by the oper- 
 ating rod G. In the case of the indicating contact D and 
 spare contact J, the contact rollers are fastened to and 
 move with the operating rod, the design causing the contacts 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 87 
 
 FIG. 63. MODEL 3 SOLENOID DWARF SIGNAL OPERATING 
 MECHANISM 
 
 F Yoke 
 
 G Operating Rod 
 
 H Roller 
 
 J Spare Contact 
 
 Operating Coils 
 Holding Coils 
 Operating Contact 
 Indicating Contact 
 Solenoid Plungers 
 
 to open with the first movement of the arm towards the pro- 
 ceed position. The roller for the operating contact C is car- 
 ried by an arm, which is raised by engagement with a collar 
 on the operating rod, when the dwarf spectacle has assumed 
 the proceed position. 
 
GENERAL RAILWAY SIGNAL COMPANY 
 
 I 
 
CROSS PROTECTION APPARATUS 
 PRINCIPLES OF G. R. S. CROSS PROTECTION 
 
 THE G. R. S. cross protection system prevents the unau- 
 thorized movement of any switch, signal, or other func- 
 tion, in the event of current being improperly applied to 
 its circuit, by the cutting off all energy from the function. 
 
 As briefly outlined in the pages on the "G. R. S. Electric 
 Interlocking System," it has been seen that all functions 
 while at rest are normally on a closed circuit of low resistance ; 
 that inserted in each of these circuits and located on the ter- 
 minal board of the interlocking machine, is a polarized relay 
 of very low resistance connected in such a manner that all 
 currents, caused to flow through the circuit by the manipu- 
 
 CIRCUIT BREAKER A 
 
 FIG. 65. SIMPLIFIED CIRCUIT SHOWING THE PRINCIPLES OF THE 
 
 G. R. S. CROSS PROTECTION SYSTEM 
 
 All functions when at rest are on closed circuit as shown by function C. 
 All normal currents will flow through the polarized relay B in the direction 
 indicated by the heavy arrows, but all currents due to a cross in the oppo- 
 site direction as indicated by the dotted arrows. Hence current supplied 
 through a cross X will open polarized relay B, which will cause circuit 
 breaker A to open and thus cut current off the system. 
 
 lation of the lever, must pass through the relay in a direction 
 to maintain its contact closed, while all currents which may 
 be applied through any other channel must pass through this 
 relay in a direction to cause it to open its contact; and that 
 this operation breaks the control circuit of the cross protec- 
 tion circuit breaker, causing it to open and cut power off that 
 section of the system affected, thereby preventing the unauthor- 
 ized movement of the function. The principles involved will be 
 made evident by reference to Fig. 65, from which circuit has 
 been eliminated all detail connections, contacts, etc., only 
 such parts being shown as are essential to the explanation. 
 
 In Fig. 64 there is shown in full circuit detail all apparatus 
 and contacts pertaining to a switch function, a signal function, 
 
90 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 91 
 
 and the system of cross protection. By tracing out these 
 circuits it will be found that the circuit conditions as shown 
 in Fig. 65 exist and afford the protection claimed. 
 
 OPERATION OP THE CROSS PROTECTION CIRCUIT BREAKER 
 
 The circuit breaker construction and its manipulation are 
 clearly illustrated by Fig. 66, the position in Fig. 66C cor- 
 responding with that of the circuit breaker in Fig. 64. The 
 various parts of the circuit breaker which make contact with 
 each other are indicated by similar letters. 
 
 It has been shown that current applied from an unauthor- 
 ized source to the circuit of a function at rest, causes the 
 polarized relay in that function's circuit to open its contact 
 and interrupt the circuit through the retaining magnet of the 
 cross protection circuit breaker. When this occurs the cir- 
 cuit breaker armature is released and the Z contacts are 
 opened, the armature falling to such a position (Fig. 66A) 
 that it cannot be drawn up against the pole pieces by the 
 magnetic pull which will be exerted when the retaining magnet 
 is again energized through the restoration of the polarized 
 relay armature. To inform the leverman that the circuit 
 breaker is open, a red lamp is lighted by the closing of the Y 
 contacts. 
 
 With the circuit breaker open as in Fig. 66A, the positive 
 and negative feeder wires between the battery and the inter- 
 locking system are opened at the Z contacts, therefore the 
 cross can have no effect. The polarized relay which had its 
 armature reversed will identify the function affected and, upon 
 the cause of the trouble being removed, the armature of this 
 polarized relay will remain in its normal position, when re- 
 placed by the operator. This will cause the retaining magnet 
 of the cross protection circuit breaker to be energized, and, 
 by raising the restoring handle to the position shown in Fig. 
 66B the circuit breaker armature is restored to its operating 
 position where it will be retained by the circuit breaker magnet. 
 This action closes the Z contacts, but at the same time opens 
 the X contacts, through which contacts are also broken the 
 positive and negative feeder wires, this preventing the appli- 
 cation of current to all functions controlled by the circuit 
 breaker until the restoring handle is returned to its normal 
 position. The red light is extinguished when the circuit 
 breaker armature is restored. 
 
 Figs. 24 and 25 illustrate a typical operating switchboard, 
 one view showing the cross protection circuit breaker exposed 
 and the other with its coyer in place. It will be noted that 
 the only portion of the circuit breaker which is accessible to 
 the leverman is the restoring handle projecting from the slot 
 at the bottom of the cover. A shield attached to this handle 
 closes this slot when the handle is in the normal position, 
 thereby protecting the internal parts against manipulation in 
 any way except by means of the restoring handle. As 
 
92 GENERAL RAILWAY SIGNAL COMPANY 
 
 explained above, so long as the handle is held in a position to 
 interfere with the release of the contacts normally retained by 
 the magnet (Fig. 66B), energy is withheld from all functions 
 under the control of the circuit breaker. These features make 
 the cross protection system fully effective at all times, even 
 though force of circumstances may require its being temporarily 
 under the charge of unskilled employees. 
 
 When it is desired to retain such signals in the proceed 
 position as may be occupying that position when the circuit 
 breaker opens, resistance units R and R! (shown dotted in Fig. 
 64) are connected so as to bridge the X and Z contacts, these 
 units permitting the flow of an amount of current sufficient to 
 hold a limited number of signals at proceed. Their resistance 
 is so high, however, that the mechanism requiring the least 
 
 FIG. 67. POLARIZED RELAY 
 
 current for its operation cannot be put in motion if energy 
 should be applied to its circuit when the circuit breaker is open. 
 The resistance units are shown in position on the operating 
 switchboard in Fig. 24. 
 
 THE POLARIZED RELAYS 
 
 The polarized relay inserted in the indication circuit of 
 each of the operated functions, and mounted on the terminal 
 board of the interlocking machine, is shown in Fig. 67. The 
 windings are so designed that the armature of the relay for 
 a switch, signal, etc., will reverse on about one-half the current 
 required to just move that function of the same type which 
 requires the least current for its operation. From this it will 
 be seen that the windings of the polarized relays used with 
 different types of functions have different resistances. 
 
 On the switchboard there is shown in Fig. 24 a polarized 
 relay similar to those mounted on the interlocking machine, 
 the position of this relay in the circuit (Fig. 64) being indi- 
 cated by the letter "A." This relay guards against crosses 
 
ELECTRIC INTERLOCKING HANDBOOK 93 
 
 between the buss bars on the interlocking machine, such as 
 might be accidently caused by the maintainer's tools when 
 he is working about the machine. From the position of the 
 relay in the circuit, it will be seen that any current reaching 
 the indication buss bar through such a cross will flow in the 
 direction opposite to that of the indication currents, this 
 causing the relay to reverse its contact in the same manner as 
 the polarized relays previously described. Since the relay on 
 the switchboard is common to all circuits, its winding is 
 designed to render it much less sensitive than those on the 
 interlocking machine. 
 
 SAFEGUARDS 
 
 To show that the system in addition to being extremely 
 simple, is also fully safeguarded, the following points are 
 mentioned : 
 
 First The closed circuit principle is employed for all 
 parts of the cross protection system. 
 
 Second All contacts or connections depended upon for 
 protection against crosses are also used in operation and, 
 hence, are checked as to their integrity every time a complete 
 operation of a function is made. 
 
 Third The polarized relay contact, in addition to opening 
 on a reversed direction of current, will also open upon loss of 
 magnetism in the permanent magnet of the relay. 
 
 Fourth An open circuit in the polarized relay prevents 
 indication. 
 
 SECTIONALIZING OF PLANTS 
 
 In connection with a comparatively simple track layout, it 
 is common practice to install only one cross protection circuit 
 breaker, which prevents the movement of all functions during 
 such time as it may be open. At busy plants having a large 
 number of routes which can be used simultaneously, it may be 
 considered undesirable to have the whole plant affected by 
 derangement at a single point, in which case the plant may 
 be divided into sections, the functions in each section being 
 controlled through separate circuit breakers. This ^ permits 
 uninterrupted operation of traffic through the sections not 
 directly affected. 
 
 In addition to the cross protection circuit breakers required, 
 it is necessary to install switchboard polarized relays and also 
 common return wires for each section in the interlocking plant. 
 The positive buss bar and indication buss bar must be divided 
 to correspond with the sectional division of the functions. It 
 is essential that there be no connections between the various 
 buss bars or the common return wires, except where they 
 join the energy mains from the battery, under the protection 
 of their respective cross protection circuit breakers. 
 
 There may be certain situations where conditions will 
 warrant the additional expense of employing individual cross 
 protection circuit breakers for each switch and each group of 
 
94 GENERAL RAILWAY SIGNAL COMPANY 
 
 signals. This would mean that a cross applied to a given 
 switch, for example, would merely make that particular func- 
 tion inoperative without interfering with any of the other 
 functions. The use of individual cross protection circuit 
 breakers requires the running of a separate return wire for 
 each of the functions or groups of functions concerned, and 
 dispenses with the main common previously mentioned. 
 
 The device (Fig. 68) employed for this purpose consists of 
 a modified form of the regular polarized relay, provided with 
 suitable contacts and a restoring handle. The contact pres- 
 sure is increased over that of the regular polarized relay, at the 
 same time retaining the relay's sensitiveness to reverse currents, 
 the contacts are heavier in design, and the iron in the magnet 
 is so distributed that a powerful magnetic blowout is obtained 
 which effectually extinguishes any arc resulting from currents 
 flowing through the contacts at the time of their opening. 
 The principles involved in the making and breaking of the 
 circuits, and in the restoration of the relay armature to the 
 operating position after having been reversed, are similar to 
 those of the cross protection circuit breaker previously de- 
 scribed. The device, as installed, is enclosed in a sealed case 
 (Fig. 69) to prevent any improper manipulation of the 
 circuit breaker parts. 
 
 This protective apparatus is mounted on the terminal board 
 of the interlocking machine, occupying the same space as the 
 regular polarized relay. The device, which is exceedingly 
 simple in construction, is in no way subjected to weather con- 
 ditions and is much more accessible than if located in the 
 field at the various switches and signals, as is the ordinary 
 practice with some systems employing individual cross pro- 
 tection. 
 
 TESTS FOR CROSS PROTECTION 
 
 It has previously been stated that all contacts and connec- 
 tions depended upon for cross protection are under a constant 
 automatic check during the regular operation of the different 
 functions; therefore tests on the cross protection system are 
 in no way requisite in the same sense that tests are necessary 
 on switch points, to determine with what maximum opening 
 the switch points can be locked. It is considered, however, 
 that the satisfaction of having a working demonstration of 
 the existence of the cross protection more than repays the 
 slight trouble involved in making it one of the points to be 
 checked up, on the regular inspection trip. 
 
 The time chosen for conducting such a test should be when 
 the voltage on the system is at the highest point attained in 
 service. This will be when the interlocking battery is being 
 charged, at which time the current will run up above 140 
 volts. 
 
 The tests on the various switch functions may be secured 
 by making a connection between the normal and reverse operat- 
 ing wires on the pole changer. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 95 
 
 FIG. 68. INDIVIDUAL CROSS PROTECTION CIRCUIT 
 
 BREAKER 
 Cover removed. 
 
 FIG. 69. 
 
 INDIVIDUAL CROSS PROTECTION CIRCUIT 
 BREAKER 
 
96 GENERAL RAILWAY SIGNAL COMPANY 
 
 In testing signals, the necessary energy may be obtained at 
 the nearest switch mechanism, since one of the switch control 
 wires is always connected to battery positive (Fig. 64). The 
 test should be made by connecting energy onto the signal 
 control wire as near as possible to the signal motor, and if the 
 signal circuit is connected to the common return wire through 
 one or more switch circuit controllers, the energy should be 
 applied to this wire, care being taken to first open the connec- 
 tion to the main common wire. Failure to open this connec- 
 tion to common in all probability will result in blowing a fuse 
 in the switch circuit from which the energy is being taken for 
 the test, since under these conditions a short circuit to the 
 common return wire is created. 
 
 Where the plant has been sectionalized, one or two functions 
 in a given section should be crossed up with wires taking energy 
 from each of the other sections. In case the functions in the 
 various sections are widely separated, these crosses may be 
 made between the binding posts in the terminal board of the 
 interlocking machine, to avoid running a conductor long dis- 
 tances over ground. This test will insure that the proper 
 division of the functions was made at the time of installation, 
 and that no undesirable connections have since been made. 
 
 For the first test after an interlocking system has been 
 installed it may be well to connect an adjustable resistance in 
 the wires used in making the crosses, starting with the resist- 
 ance all in and gradually cutting it down until the circuit 
 breaker opens. For the periodical tests which some railway 
 companies carry out this resistance is generally considered 
 unnecessary. 
 
ACCESSORIES 
 
 MODEL 3 FORM D SWITCH CIRCUIT CONTROLLERS 
 
 FIG. 70. MODEL 3 FORM D SWITCH 
 
 CIRCUIT CONTROLLER 
 Two circuits, normal or reverse. 
 
 FIG. 71. MODEL 3 FORM D 
 
 SWITCH CIRCUIT CONTROLLER 
 
 Two circuits normal and two 
 
 reverse. 
 
 FIG. 72. MODEL 3 FORM D SWITCH 
 
 CIRCUIT CONTROLLER 
 Four circuits normal and four reverse. 
 
f 
 
 98 GENERAL RAILWAY SIGNAL COMPANY 
 
 MODEL 5 FORM A SWITCH CIRCUIT CONTROLLER 
 
 The Model 5 Form A switch circuit controller arranged for 
 selecting signal circuits is shown by Figs. 73, 74 and 75. The 
 operation of the contacts, which are forced open and forced 
 closed, is effected through a cam movement, which causes 
 all wear to come on heavy iron parts and not on the contacts. 
 
 The contacts may be adjusted in pairs to make normal or 
 reverse contact as required. One pair is adjusted by 
 means of the screw jaw on the connecting rod and the other 
 pair by means of the cam (Fig. 187), the parts after adjust- 
 ment being positively locked against working loose. The 
 contacts and binding posts are mounted on a vertical panel 
 which gives convenient access to the binding posts when 
 "connecting up " and permits ready inspection of the contacts. 
 
 FIG. 73. MODEL 5 FORM A SWITCH CIRCUIT CONTROLLER 
 
 Two circuits normal and two reverse, or four circuits normal, or four 
 
 circuits reverse. 
 
 The case is provided with main and supplementary covers 
 as shown by Fig. 74, the latter protecting the contacts from 
 frost and condensation at all times, and when the main cover 
 is open, from rain. The trunking cap and operating crank 
 may be applied to either side of the circuit controller as proves 
 most convenient in installation. 
 
 THREE POSITION D. C. MOTOR RELAY 
 
 The Three Position D. C. Motor relay is especially designed 
 for wireless control automatic block signaling, but is readily 
 adapted for use with three position polarized line circuits. 
 
 The operating mechanism consists of a small direct current 
 motor having powerful permanent magnet fields with ample 
 air gap between the armature and pole pieces. The contacts 
 are moved from the de-energized position to either of the 
 
ELECTRIC INTERLOCKING HANDBOOK 99 
 
 FIG. 74. MODEL 5 FORM A SWITCH CIRCUIT CONTROLLER FOR SELECTING 
 SIGNAL CIRCUITS MAIN AND SUPPLEMENTARY COVERS OPEN 
 
 FIG. 75. MODEL 5 FORM A SWITCH CIRCUIT CONTROLLER FOR SELECTING 
 
 SIGNAL CIRCUITS MAIN COVER OPEN 
 
 Two circuits normal and two reverse, or four circuits normal, 
 or four circuits reverse. 
 
100 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 energized positions by the rotary motion of the motor armature, 
 the movement of which is transmitted to the contacts by 
 suitable link connections. The closing of one or the other 
 sets of contacts is accomplished by a partial rotation of the 
 armature, the direction being dependent on the polarity of 
 the operating current. 
 
 The contacts have the same opening and pressure, and are 
 similar in design t'o those used in the regular Model 9 D. C. 
 relay. The maximum equipment of contacts in the four way 
 relay, shown in Fig. 76, is four normal and four reverse, 
 with four contacting fingers. It is to be noted that when 
 used in connection with wireless signaling on polarized track 
 work, the signal control is broken through one set of con- 
 
 FIG. 76. THREE POSITION D. C. MOTOR RELAY 
 Four way. 
 
 tacts only, while in the polar-neutral relay the control must 
 be broken through both polar and neutral contacts. This 
 same holds true for the track control, which, owing to 
 the decreased resistance of the contacts introduced into the 
 circuit, means that cut-sections can be employed to as great 
 an extent in polarized track circuit work, through the use of 
 this relay, as in the case of neutral track circuits employing 
 the ordinary two position relay. 
 
 The relay has several other important features which should 
 be noted. The design is such that the chance of having the 
 polarity reversed by a large flush of current or by lightning is 
 so remote as to be negligible. The relay is not subject to 
 residual magnetism troubles in any way, as its operation 
 depends on current only, and not on electro-magnetic traction. 
 This being the case, the drop away (50 per cent, of the normal 
 pick up) cannot change with time, and once fixed, always 
 
ELECTRIC INTERLOCKING 'HANDBOOK 1 
 
 101 
 
 remains the same. The overall dimensions are* such *&&' "to 
 permit its installation in the space required by a D. C. tractive 
 type relay having the same contacting capacity. 
 
 TRACTIVE TYPE D. C. RELAYS 
 
 FIG. 77. 
 
 MODEL, 9 D. C. SHELF RELAY 
 Four way. 
 
 FIG. 78. 
 
 MODEL 9 D. C. WALL RELAY 
 Four way. 
 
102 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 103 
 
 TRACK DIAGRAMS AND MANIPULATION CHARTS 
 
 To facilitate the manipulation of the levers of the inter- 
 locking machine, it is customary to mount within full view of 
 the leverman a diagram of the track layout showing the rela- 
 tive location of all interlocked switch and signal functions, 
 also a chart listing the various routes through the plant and 
 the order in which the levers are to be moved in setting up 
 each of these routes. By referring to the chart, the leverman 
 is guided in manipulating the levers in the sequence imposed 
 by the mechanical locking between levers, thus aiding him 
 greatly in the handling of the traffic passing through the plant. 
 
 FIG. 80 FIG. 81 
 
 MODEL 9 D. C. INDICATOR 
 
 Four way. 
 
 The track diagram and manipulation chart are usually com- 
 bined in one plan and mounted in a single frame, unless their 
 combined size is prohibitively large, in which case they are 
 framed separately. 
 
 INDICATORS 
 
 For a long time it has been customary to give to the lever- 
 man an indication of the trains approaching the interlocking 
 plant; with the advent of route locking and the semi-auto- 
 matic control of signals, and the consequent general use of 
 track circuits within the interlocking limits, this practice has 
 been extended to indicating at the interlocking station, the 
 
104 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 82. 
 
 MODEL 9 D. C. INDICATOR GROUP 
 Cover removed. 
 
 condition of all the track sections within the plant. This 
 supplements the information given by the track diagram and 
 manipulation chart, and adds considerably to the facility 
 with which the traffic is handled. 
 
 The approach sections are usually repeated by disc indicators 
 and the different track sections between the home signal 
 limits by semaphore indicators. These are generally located 
 on the wall of the operating room near the track diagram, 
 
 FIG. 83. MODEL 9 D. C. INDICATOR GROUP 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 105 
 
 FIG. 84. MODEL 9 D. C. INDICATORS. LAKE STREET INTERLOCKING 
 PLANT, CHICAGO TERMINAL, C. & X. W. R'Y 
 
 being mounted either separately with individual covers or on 
 a common frame with a single cover. The indicators, as shown 
 by Figs. 81 and 82, may be equipped with contacts and thus 
 perform the functions of a relay in addition to those of a 
 repeater. 
 
 ILLUMINATED TRACK DIAGRAMS 
 A method of indicating the occupancy or non-occupancy 
 of the various track sections, rather more elaborate than by 
 the use of repeating indicators, is through the employment of 
 the illuminated track diagram. This type of indicator is 
 of great assistance on extremely busy plants where it is 
 necessary to know when a train has cleared each route or 
 
106 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
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SECTION III 
 
 G. R. S. ALTERNATING CURRENT 
 APPLIANCES 
 
 DESCRIBING A. C. RELAYS AND THEIR 
 USE IN INTERLOCKING WORK; ALSO 
 SINGLE AND DOUBLE RAIL A. C. 
 TRACK CIRCUITS, AND TRANSFORMERS 
 
ALTERNATING CURRENT RELAYS 
 
 THE following pages have been written with the object of 
 acquainting those interested in this type of apparatus 
 with the principal characteristics and proper application 
 of the various alternating current relays manufactured by the 
 General Railway Signal Company. 
 
 POINTS TO BE CONSIDERED IN SELECTING AN ALTERNATING 
 CURRENT RELAY 
 
 In selecting any alternating current relay for a given purpose, 
 the following should be taken into consideration : 
 
 First Is the device to be used as a track relay or a line relay? 
 
 If it is to be employed as a track relay, in all proba- 
 bility it will be exposed to the influence of traction or foreign 
 currents, and must, therefore, be of such design that it will not 
 respond to currents other than that intended for its operation. 
 Furthermore, if the track circuits are very long or the ballast 
 very bad, or if the relay is to be located a long distance from 
 its point of connection to the rails, the relay should necessarily 
 require very little energy from the rails in order to avoid cut 
 sections or undue energy consumption. On the other hand, 
 when the opposite conditions exist, these relays need not be 
 so highly efficient and consequently may be smaller and less 
 expensive. 
 
 If required for use as a line relay the device will rarely be 
 installed where it will be exposed to the influences of foreign 
 or traction currents, and when such is the case, can be of 
 simpler, smaller, and less expensive design. 
 
 Second Is two or three position operation required? 
 
 In this connection it should be noted that the amount of 
 line wire can frequently be reduced by the employment of 
 relays which have normal, reverse, and de-energized positions. 
 To secure the equivalent of this using two position relays it 
 may be necessary to install twice as many relays and additional 
 line wire. A concrete example of this is the application of 
 three position relays to polarized track circuit work in which 
 the caution and clear positions of a signal are given over the 
 track rails by reversing the polarity, and without the use of 
 line wires at all. 
 
 Third How many and what kind of contacts is the relay 
 to have? 
 
 It frequently happens that as many as ten or twelve 
 contacts are required and that these contacts must carry 
 at comparatively high voltage a large amount of current; 
 in other cases but few contacts and these carrying very 
 light currents are necessary. Furthermore, contacts equipped 
 with "magnetic blowouts" may be needed to extinguish arcs 
 which otherwise would be established in the handling of heavy 
 direct currents. These are features which often determine 
 the selection of the relay. 
 
110 GENERAL RAILWAY SIGNAL COMPANY 
 
 Fourth Generally speaking, the question of whether a 
 relay is to be of high or low efficiency, and whether it would 
 pay to spend more or less for it, should be decided on the same 
 basis that is used in selecting any piece of apparatus, viz: 
 having determined the total cost of the device in place, includ- 
 ing any necessary auxiliary devices, it is then proper to esti- 
 mate the cost of the energy required for its operation, and 
 that relay which will answer the purpose and cost the least, 
 considering first cost, energy consumption, maintenance charges, 
 interest, and depreciation, should, of course, be the one to use. 
 
 MODEL 2 FORM A POLYPHASE RELAY 
 
 The Model 2 Form A relay is especially designed for power- 
 ful and efficient operation on very long track circuits. As 
 
 FIG. 86. MODEL 2 FORM A POLYPHASE RELAY 
 Four way. 
 
 an evidence of this efficiency, it may be pointed out that with 
 minimum energy consumption it has given perfect operation on 
 track circuits of from three to four miles in length, and with 
 ballast conditions far from favoring good track circuit operation. 
 The relay is operated by a polyphase motor, which consists 
 of a non-magnetic rotating shell or "rotor," and fixed inner 
 and outer cores, the outer core being the "stator" on which 
 the windings are placed. These windings are designed and 
 connected so as to produce (with alternating current applied) 
 a rotating magnetic field, which in turn will induce currents in 
 the non-magnetic rotor causing it to operate. (Direct currents 
 cannot produce this rotary field and, therefore, cannot cause 
 operation.) The rotor is ordinarily connected to the con- 
 tacts through the medium of a pinion and sector arrangement, 
 thereby multiplying the effect of the rotor and permitting the 
 operation of a large number of contacts with a very small 
 
ELECTRIC INTERLOCKING HANDBOOK 111 
 
 amount of energy applied. Furthermore, as it is possible to 
 supply most of the energy to the stator from a local source, 
 only a small amount of energy is required from the rails to 
 cause the relay to operate. These two points permit the 
 operation of very long track circuits without the use of cut 
 sections or undue energy consumption. 
 
 The relay is universal in its application, in that it may be 
 wound for operation on steam roads, electric roads using 
 either A. C. or D. C. propulsion, or for operation as a line 
 device. Furthermore, it can be adapted for use on any 
 frequency current, for two or three position operation, and 
 may be made fast or slow acting. 
 
 The contacts are unusually heavy in construction and are 
 so designed that any combination of front, back, or front and 
 back contacts can be secured, changes being easily made on 
 the ground if desired. Special contacts equipped with the 
 "magnetic blowout" referred to on page 109 can also be fur- 
 nished. The contact housing for the four and six way relays 
 accommodate eight and twelve contact fingers, respectively, 
 these controlling eight or twelve independent circuits. 
 
 MODEL 2 FORM B RELAY 
 
 The Model 2 Form B relay operates on the same general 
 principles as the Model 2 Form A, employing the non-mag- 
 netic rotor which permits it to operate with the same degree 
 of safety and reliability. It is designed primarily to operate 
 as a line device but may be used in connection with track 
 circuits to a limited extent; for instance, as a track relay for 
 short track circuits on steam roads, or for short double rail 
 track circuits on roads using direct current for propulsion. 
 While the relay's efficiency is approximately but half that of 
 the Model 2 Form A it compares well, nevertheless, with other 
 A. C. relays on the market. It operates on 25 or 60 cycle 
 current, in two or three positions, and can be furnished either 
 slow or quick acting. 
 
 The Model 2 Form B relays have about the same overall 
 dimensions as a D. C. relay of the same contact capacity, this 
 feature permitting their installation in housings previously 
 occupied by D. C. relays. The relay is assembled as a shelf 
 or wall type device, as a tower indicator or as an interlocking 
 relay. The contacts are limited to a maximum of four 
 front and two back, or six front and two back," in the four 
 and six way relays, respectively. 
 
 MODEL 3 FORM B RELAY 
 
 In the Model 3 Form B relay, the same construction is used 
 for the housing, contact arrangement, etc., as in the Model 
 2 Form B. The actuating movement is essentially the same 
 as that of the Model 2 Form B, with the exception that it 
 operates in two positions only and is a single phase device. 
 
112 GENERAL RAILWAY SIGNAL COMPANY 
 
 Due to this feature the relay does not require the presence of 
 local energy which is sometimes difficult to provide for. The 
 relay is equipped with a non-magnetic rotor and is designed 
 primarily for use in connection with single rail track circuits 
 on direct current electric traction roads. 
 
 MODEL Z FORM B RELAY 
 
 The Model Z Form B relay uses the same housing and is 
 provided with contacts of the same design and arrangement 
 as the Model 2 Form B and Model 3 Form B relays previously 
 described. 
 
 The Model Z relays are provided with a bipolar stator, 
 with windings on each of the poles, and a rotary armature so 
 
 FIG. 87 
 
 MODEL 2 FORM B, A. C. RELAY 
 MODEL 3 FORM B, A. C. RELAY 
 MODEL Z FORM B, A. C. RELAY 
 
 Six way. 
 
 shaped that when current (either direct or alternating) is 
 applied to the windings, a uniform torque is produced, which 
 causes the rotor to operate through about ninety degrees. 
 This movement is transmitted by means of a suitable connec- 
 tion to the contacts. 
 
 Being operable on direct current, the relay is adapted for 
 line service only. Its exceptionally high efficiency makes it 
 preferable for this type of work where direct current does not 
 exist on the line and where single phase operation is desired. 
 The relay operates in two positions only. 
 
 In conclusion, attention is directed to the comparatively 
 few types of relays needed to cover the full range of require- 
 ments of A. C. signaling. 
 
ELECTRIC INTERLOCKING HANDBOOK 113 
 
 It will be noted by reference to the description which has 
 preceded : 
 
 First That but two general forms of construction are 
 employed, viz: the larger, more efficient form (Fig. 86), 
 especially adapted for track circuit work, and the small, mod- 
 erately efficient form (Fig. 87), especially designed for line 
 circuits and short track circuits. 
 
 Second That but two principles of operation are used, 
 namely : the inductive as employed in the Model 2 and Model 3 
 relays, and the electro-magnetic as employed in the Model Z 
 relays. 
 
 Third That each form is made in two sizes to accommodate 
 more or less contacts as required. 
 
 With these two forms, two principles of operation and 
 two sizes of relays, wound and equipped with contacts as may 
 be necessary, all the requirements of A. C. signaling can be 
 met without resorting to a greater number of types. It will, 
 therefore, be seen that the G. R. S. relay construction has 
 placed A. C. relays, as regards the diversity of types required, 
 on practically the same basis with the relays used in connec- 
 tion with D. C. signaling. 
 
SINGLE RAIL ALTERNATING CURRENT 
 TRACK CIRCUITS 
 
 SINGLE rail A. C. track circuits are largely used at inter- 
 locking plants in electrified territory. With this type of 
 track circuit, insulated joints are placed in one rail only, 
 the other rail being used in common by the return propulsion 
 current and the signaling current (see Figs. 88 and 89). It 
 will be seen that single rail track circuits are used to best ad- 
 vantage where there are two or more parallel tracks, in 
 that the power or common rail of all these tracks can be bonded 
 together, thus preventing interruption of the propulsion current 
 return in the event of a break in the power bonding in any one 
 of the continuous rails. 
 
 ADVANTAGES 
 
 The chief advantage of single rail track circuits as compared 
 to the double rail type is in its lesser cost and complication, 
 the double rail circuits requiring the installation of impedance 
 bonds to provide a continuous return for the propulsion cur- 
 rent. As there are usually a number of comparatively short 
 track circuits at an interlocking plant, it is seen that the use 
 of double rail track circuits with impedance bonds would be 
 very expensive. It is furthermore true that at many plants, 
 the track arrangement is such that it would be extremely 
 difficult to secure space at the bond locations for their installa- 
 tion. 
 
 LIMITATIONS 
 
 Traction Return. When single rail track circuits are in- 
 stalled, both rails cannot be retained for traction purposes, as 
 noted above. If the giving up of one rail leaves insufficient 
 return for the propulsion current, the use of single rail track 
 circuits is barred and double rail track circuits would probably 
 have to be employed. 
 
 Broken Rail Protection. Single rail track circuits do not 
 give broken rail protection due to the cross bonding required 
 for traction purposes, which provides a number of return 
 paths through the rails of other tracks for the signaling current. 
 On this account the use of single rail track circuits should be 
 restricted to slow speed tracks, such for example as in terminals, 
 or to siding tracks. 
 
 Length. The permissible length of single rail track circuits 
 is limited either by ballast conditions, by the traction drop in 
 the return rail between the points of connection of the trans- 
 former and the track relay to the common rail, or by the com- 
 bination of ballast and drop. The Model 2 Form A relay as 
 ordinarily constructed is capable of carrying 10 amperes direct 
 current through its track winding without overheating or 
 being caused to open. 
 
 The drop in the common rail has the effect of sending direct 
 current from the common rail through the transformer, through 
 
ELECTRIC INTERLOCKING HANDBOOK 115 
 
 the signaling rail, the track winding of relay and back to the 
 common rail, this effect being maximum when a train is on 
 the transformer end of the track circuit, thereby cutting out 
 the transformer resistance and allowing the full drop to be 
 effective through the signaling rail and relay in series. 
 
 In view of the fact that the common return rail has a neg- 
 ligible resistance, there are times when it can be assumed that 
 all of this drop is effective across the relay, and to prevent a 
 prohibitive amount of direct current from flowing through 
 the relay, under ordinary conditions a limiting resistance is 
 added in series with the relay. 
 
 If however the track circuit is long or the ballast bad, the 
 traction drop will in all probability be excessive, thereby 
 requiring that the limiting resistance be high, which in turn 
 necessitates that a correspondingly high A. C. voltage be 
 impressed across the rails at the relay location in order to 
 secure operation; this A. C. voltage is limited since as the 
 voltage is increased the current leakage between the rails 
 throughout the length of the track circuit increases very 
 rapidly. To take care of such a condition an impedance hav- 
 ing low ohmic resistance to direct current, but high resistance 
 to alternating current, may be shunted across the relay ter- 
 minals, this permitting a large amount of direct current 
 to flow through the relay and impedance combined with- 
 out causing more than 10 amperes direct current to flow 
 through the relay; a unit of low resistance is still required, 
 being connected in series with the relay and impedance, this 
 resistance necessarily being in the nature of a grid since it 
 has to carry a comparatively large amount of direct current. 
 With this arrangement the transformer should be designed to 
 stand a large amount of direct current through its secondary 
 winding without having its A. C. voltage seriously affected. 
 
 Under the conditions ordinarily found in terminals or where it 
 is permissible to use single rail track circuits, it will be found that 
 the use of a resistance in series with the relay is adequate to se- 
 cure proper operation, it being necessary only in rare cases to em- 
 ploy the impedance shunted around the terminals of the relay as 
 above described. 
 
 ENERGY REQUIRED 
 
 The energy required for the operation of single rail track 
 circuits depends upon the amount of traction drop in the com- 
 mon rail and upon the ballast conditions. In an interlocking 
 plant where the track circuits may average 500 feet in length, 
 the energy per track circuit, employing the Model 2 Form A 
 track relay, should not exceed the figures given below: 
 
 Total Energy Required for Track 
 Circuit and Relay Local 
 
 25 cycle current, 30 volt amperes 25 watts 
 
 60 cycle current, 40 volt amperes 30 watts 
 
 NOTE. The Model 2 Form A track relay, quick acting and designed to 
 stand 10 amperes direct current, has a resistance of about one-half ohm. 
 
116 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TYPES OF SINGLE RAIL TRACK CIRCUITS 
 
 In the past the common practice when installing single 
 rail A. C. track circuits has been to locate the track trans- 
 former at one end of the track circuit and the relay with its 
 housing and auxiliary apparatus at the other end; this re- 
 quires that the relay must be repeated into the interlocking sta- 
 tion to operate other relays or indicators. A simplified dia- 
 gram of such a circuit is illustrated by Fig. 88. 
 
 In sharp contrast with this is shown in Fig. 89, the method 
 which can be used when a high efficiency polyphase relay such 
 as the Model 2 Form A is employed. By feeding the track 
 circuit from a central source and extending the relay leads 
 
 INTERLOCKING STAT\ON LIMITS 
 
 r 1 
 
 r 
 
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 HIGH VOLTAGE. 1 
 
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 WV PRIMARY 
 
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 A/vJ 
 
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 Wd 
 
 TRANSFORMER 
 
 
 
 
 COMMON RETURN RAIL 
 
 
 
 
 
 
 i i 
 
 TRACK 
 
 
 RELAY 
 
 . 
 
 FIG. 88. SINGLE RAIL A. C. TRACK CIRCUIT 
 Track relay and transformer located at track circuit. 
 
 from the track circuit into the station, the amount of apparatus 
 can be cut down, maintenance costs reduced to a minimum, 
 and certain safety features, not obtainable in the other arrange- 
 ment, secured. 
 
 It will be noted that in the central energy scheme, the 
 vital parts of the track circuit are located in the station directly 
 under the eye of the maintainer which permits adjustments to 
 be made under the most favorable conditions. Due to the 
 simplicity and accessibility of this type of track circuit, main- 
 tenance is reduced to a minimum. 
 
 A considerable amount of apparatus is saved by this kind of 
 an installation, since secondary relays with their track boxes, 
 additional wiring and fusing, are not required : furthermore, 
 the numerous track transformers which otherwise would have 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 117 
 
 to be distributed from one end of the interlocking plant to 
 the other are eliminated due to the circuits being fed from one 
 central point. The resistance of the leads from the track 
 circuit to the relay and transformer, constitute a part of the 
 limiting resistance required in series with these pieces of ap- 
 paratus. 
 
 A safety feature obtainable in the central energy scheme 
 which cannot be overlooked is in the protection against crosses. 
 It will be noted by reference to Fig. 88 that a cross at X will 
 cause false operation of the repeating relay in the station, 
 whereas a similar cross in Fig. 89 prevents, as it should, 
 operation of the relay. Every step toward simplicity is a 
 
 INTERLOCKING STATION LIMITS 
 
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 (INDICATING) 
 
 
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 ^s MULTIPLE CONDUCTOR 
 
 BONDED TO ALL COMMON 
 RETURN RAILS 
 
 n 
 
 
 
 J 
 
 ALL OTHER COMMON RETURN RAILS 
 
 FIG. 89. SINGLE RAIL, A. C. TRACK CIRCUIT 
 Central energy scheme. 
 
 step towards safety and this central energy control is the 
 last word in simplicity as regards track circuits. 
 
 The high efficiency of the Model 2 Form A relay especially 
 adapts it for this kind of work, the relay requiring but a small 
 amount of current from the rails, while a comparatively large 
 amount is supplied at the station for the local phase of the relay. 
 The relay may be equipped with an indicator blade and 
 located in plain sight of the leverman, thus dispensing with the 
 necessity of repeating indicators which might otherwise be 
 required for this purpose. 
 
 TYPICAL INSTALLATION OF THE CENTRAL ENERGY SCHEME 
 
 Fig. 90, which is typical of a large G. R. S. installation, 
 illustrates the extension of the principle of Fig. 89 into the 
 complete wiring required in connection with this type of track 
 
118 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Interlocking Station Limits 
 
 Controller 
 On lever tatch 
 A.c Lock on 
 5n lever 
 
 FIG. 90. SECTION OF INTERLOCKING PLANT 
 Showing use of central energy scheme for track circuit control. 
 
ELECTRIC INTERLOCKING HANDBOOK 119 
 
 circuit work. It also indicates the control between the inter- 
 locking machine and the switch and signal functions in the 
 given section of track, and shows the method of controlling 
 the switch lever locks and track indicators through the track 
 relay. 
 
 The track relays and transformers are shown located in the 
 station, the latter being installed in duplicate to prevent any 
 interruption of service should anything happen to one of 
 the transformers. It will be noted that the transformers, 
 besides feeding the track circuits, are used to furnish energy 
 for the signal lighting and the operation of all A. C. appa- 
 ratus. The track winding of these transformers is brought to 
 a buss bar on the distributing switchboard, the individual 
 leads of the various track circuits being connected to this buss. 
 It is general practice where the track circuits vary sufficiently, 
 or where any of them are located far enough from the station 
 to require much more voltage than the others, to provide the 
 track winding of the transformer with a number of taps which 
 are carried to different buss bars, the individual leads of the 
 different track circuits being taken from one buss or the 
 other as required. 
 
IMPEDANCE BONDS FOR DOUBLE RAIL 
 
 ALTERNATING CURRENT TRACK 
 
 CIRCUITS 
 
 WHEN it is desired to install A. C. track circuits and 
 both rails must be retained for propulsion purposes, 
 double rail track circuits, such as are shown by the 
 typical circuit, Fig. 238, must be employed. It will be noted 
 that the track is divided into sections of varying length by 
 
 FIG. 91. METHOD OF INSTALLING SIZE 1 FORM C IMPEDANCE BONDS 
 
 means of insulated rail joints. Impedance bonds are installed 
 at such locations for the purpose of providing around the joints 
 a low resistance path for the return D. C. propulsion current, 
 while not permitting the passage of the A. C. signaling current. 
 The bonds consist of a few turns of heavy copper wound 
 about, but insulated from, a laminated iron core, the con- 
 nections to the rails being so made that the traction current 
 has no magnetic effect on the bond, provided an equal amount 
 is flowing in each of the rails. If, however, more current is 
 flowing in one rail than in the other, there will be a tendency 
 to saturate the iron core and thereby reduce the impedance 
 of the bond. This effect, which is called "unbalancing," 
 is limited by introducing an air gap into the magnetic circuit, 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 121 
 
 the bonds ordinarily being designed to stand 20 per cent. 
 unbalancing without a decrease of more than 10 per cent, in 
 impedance. 
 
 The size of the bond to be installed is dependent upon the 
 amount of current the bond will have to carry, the impedance 
 to which it must be wound (this being more or less dependent 
 upon the length of the track circuit), and upon the amount of 
 unbalancing to be taken care of. Where good traction bond- 
 ing can be maintained a less amount of unbalancing can be 
 figured upon, and hence a smaller size of bond employed. 
 
 
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 FIG. 92. 
 
 METHOD OF INSTALLING SIZE 2 FORM B AND SIZE 3 
 FORM A IMPEDANCE BONDS 
 
 Dimension 
 
 Size 2 Form B Bond 
 
 Size 3 Form A Bond 
 
 A 
 B 
 C 
 
 20% inches 
 24y 2 inches 
 13% inches 
 
 18% inches 
 17% inches 
 11% inches 
 
 The Size 1 Form C bond, which is the largest, is installed 
 only where the heaviest traffic requirements are to be met, the 
 size of the bond requiring that it be located outside of the rails. 
 The Size 2 Form B and Size 3 Form A bonds are of such dimen- 
 sions as to permit their being installed between the rails. 
 These smaller bonds are furnished with sloping covers to pre- 
 vent their being caught by dragging train parts, and are 
 especially designed to have their leads brought out of the case 
 in a manner to facilitate connection to the rails. 
 
TRANSFORMERS 
 HIGH TENSION LINE TRANSFORMERS 
 
 THE Type L transformer is a single phase, oil immersed, 
 self cooled, pole type transformer, designed to step down 
 the transmission line voltage (6,600 volts maximum) at 
 signal and track feed locations, to the voltage required for the 
 operation of the signal system. 
 
 FIG. 93. 
 
 VIEW OF TYPE L TRANSFORMER SHOWING 
 TERMINAL BOARDS 
 
 FIG. 94. TYPE L HIGH TENSION LINE TRANSFORMER 
 
 The combinations in which these transformers are made up 
 are as follows : 
 
 1. High tension primary winding and low tension secondary 
 winding for feeding relay locals, signal mechanisms, and lights. 
 
 2. High tension primary winding and low tension secondary 
 winding for feeding track circuits. 
 
ELECTRIC INTERLOCKING HANDBOOK 123 
 
 3. High tension primary winding and low tension secondary 
 windings, one for feeding relay locals, signal mechanisms and 
 lights, and one or two for feeding track circuits. 
 
 The primary or high tension winding may be equipped 
 with 5 and 10 per cent, taps brought to a suitable porcelain 
 terminal block, which ordinarily is located below the oil 
 level to minimize the liability of lightning arcing from post to 
 post. The secondary leads and taps are brought to a sepa- 
 rate porcelain terminal board located above the oil level. 
 
 The transformer windings are contained in a cast iron, 
 water-proof case, which is fitted with lugs to take the hanger 
 irons necessary for mounting. 
 
 These transformers are built with the same relative polarity 
 and are so constructed that reversing the polarity of the track 
 feed may be accomplished on the terminal block inside the 
 transformer without changing the permanent exterior circuit 
 connections. 
 
 FIG. 95. TYPE K SECONDARY TRACK TRANSFORMER 
 
 Core losses and copper losses are lower and the efficiency 
 higher than usually is obtainable on this special class of trans- 
 formers. Good regulation on low power factor, low exciting 
 current and high insulation (insulation tests being 50 per cent, 
 above A. I E. E. standards) are features which combine 
 to form an exceptional transformer in point of long life and 
 safety. The transformer design is strictly in accordance with 
 R. S. A. specifications. 
 
 SECONDARY TRACK TRANSFORMERS 
 
 The Type K secondary track transformer as illustrated by 
 Fig. 95 is of the air cooled type and is especially designed 
 for feeding individual track circuits, being used, however, to 
 some extent, in connection with low voltage tungsten light- 
 ing. 
 
 The transformers are ordinarily made up with one high 
 tension primary winding and one low tension secondary 
 winding, this latter being provided with taps for the adjust- 
 ment of the track circuit feeds. The primaries are wound 
 for any voltage up to 440 as specified and as ordinarily 
 installed are connected to the low tension secondary of the 
 line transformer. These connections can be made and the 
 
124 GENERAL RAILWAY SIGNAL COMPANY 
 
 track transformer housed in the relay box ordinarily installed 
 at signal locations. 
 
 The cover of the transformer is provided with binding posts 
 for both high and low tension windings. The case is of cast 
 iron, light in weight, and is provided both with lugs for hang- 
 ing, and with feet to permit of the device being mounted as 
 desired. 
 
 The same exceptional efficiency, regulation, and low exciting 
 current are obtained in this class of transformer as in the Type 
 L transformers, previously described. 
 
SECTION IV 
 
 SIGNAL LIGHTING AT INTERLOCKING 
 PLANTS 
 
 COVERING RECOMMENDED PRACTICE 
 FOR ELECTRIC LIGHTING AS TO THE 
 ARRANGEMENT OF LAMPS,. SOURCE 
 OF POWER, AND PRECAUTIONS TO 
 OBSERVE 
 
SIGNAL LIGHTING AT INTERLOCKING 
 PLANTS 
 
 THE question as to whether oil or electricity is to be used 
 for lighting the signals at electric interlocking plants, de- 
 pends on what is most economical and satisfactory under 
 the particular conditions existing at each separate plant. 
 
 In many cases a decision as to the type of lighting best 
 adapted to a given plant can be easily reached. For example : 
 If commercial power of proper voltage is available at low 
 cost, or if alternating current is employed in connection with 
 the signaling, it will undoubtedly be found desirable to light 
 the lamps electrically; this is especially so if the plant is a 
 very large one, as at such a point the oil lamps would require 
 a special force of lampmen for their maintenance. On the 
 other hand, if commercial power is not available or can be 
 secured only at a high rate, or if the plant is so small that oil 
 lamps could be cared for by the force regularly employed, it 
 will probably be found most economical to use oil lighting. 
 
 In cases where the course to be followed is not so evident, a 
 careful estimate of the initial expense involved and of the cost 
 of operation and maintenance, should be prepared before a 
 decision is reached. In the case of oil lighting it is merely 
 necessary to consider the cost of the lamps, oil, maintenance, 
 etc. In the case of electric lighting, however, a number of 
 other considerations enter into the problem as outlined on 
 the following pages. 
 
 TYPE AND ARRANGEMENT OF BULBS IN SIGNAL LAMPS 
 
 The bulbs used in this type of work are ordinarily of low 
 candle power, it having been found that ample light is secured 
 from bulbs of two or four candle power. When the lighting is 
 operated at 110 volts, the carbon filament type is installed, it 
 being considered that metallic filament bulbs of such low 
 candle power are too frail to be reliable when designed for 
 operation on this voltage. Where it is possible, however, to 
 furnish current at a potential of from 6 to 12 volts, the high 
 efficiency of the metallic filament type can readily be made 
 use of. 
 
 POWER REQUIRED FOR OPERATION OF 
 INCANDESCENT LAMPS 
 
 
 CARBON FILAMENT 
 
 METALLIC FILAMENT 
 
 Candle 
 Power 
 
 110 Volts 
 
 55 Volts 
 
 10-13 Volts 
 
 4-6 Volts 
 
 
 Watts 
 
 Watts 
 
 Watts 
 
 Watts 
 
 2 
 
 10 
 
 10 
 
 .. 
 
 2V 2 
 
 4 
 
 20 
 
 20 
 
 5 
 
 5 
 
 NOTE. Values approximate. 
 
128 GENERAL RAILWAY SIGNAL COMPANY 
 
 In determining the arrangement of the bulbs in each signal 
 lamp, the first consideration is to insure the signals against 
 ever being without light. On this account, general practice has 
 been to have each signal lamp contain two bulbs, connected 
 in multiple, it being highly improbable that both will burn 
 out at the same time. The reduced brilliancy of the signal 
 light, resulting from the burning out of one of the bulbs, 
 causes the failure to be quickly detected and permits the 
 necessary renewal to be made at once. 
 
 Where two bulbs, burning in multiple, give more than the 
 amount of light required, an economy can be effected without 
 sacrificing reliability by employing "cut in" relays which 
 permit the burning of but one of the bulbs at a time. The 
 coil of this "cut in" relay is connected in series with the bulb 
 that is to burn normally, a back contact on the relay being 
 arranged to connect the reserve bulb across the lighting mains 
 in the event of failure of the one in service. 
 
 Another way to reduce the energy consumption and still 
 retain the necessary reserve, is to use the high efficiency 
 metallic filament bulbs connected in multiple. As stated 
 above, a low candle power bulb of this type to be reliable 
 must be operated on low voltage. 
 
 NORMAL SOURCE OP POWER AND THE NECESSARY RESERVE 
 
 Having touched upon -the type and arrangement of the 
 bulbs to be used in signal lamps, the next consideration should 
 be with regard to the normal power supply and what reserve 
 should be provided to keep the lights burning in case of 
 emergency. 
 
 It is recommended as good practice that the signal lights 
 should be operated from a commercial source, the control 
 being arranged so that the lighting systems will be quickly 
 transferred on to the 110 volt interlocking battery in the 
 event of failure of the commercial power. It will be seen 
 that this use of the interlocking battery as a reserve restricts 
 the lighting to operation on 110 volts. The commercial power 
 may be either alternating or direct current and will in all 
 probability be delivered at 110 or 220 volts. If this potential 
 is 220 volts, it is, of course, necessary to install a motor gen- 
 erator set, transformer, etc., to reduce the voltage to that 
 required by the lighting system. 
 
 Where a reliable source of alternating current is available, 
 such, for instance, as can be obtained when the interlocking 
 plant is located in A. C. automatic signal territory, the reserve 
 battery is not considered necessary, and this permits the light- 
 ing system to be operated at any voltage desired. In such a 
 case low voltage metallic filament lamps can be operated, 
 transmission about the plant being made at a higher voltage, 
 thus avoiding the necessity of installing large lighting mains. 
 In this connection it is to be noted that low voltage lighting 
 should be restricted to points where the current supply is abso- 
 
ELECTRIC INTERLOCKING HANDBOOK 129 
 
 lutely reliable, except in the case of a plant with compara- 
 tively few signals, at which plant a low voltage battery of 
 suitable capacity is available for use as a reserve. 
 
 In case commercial power, of the proper voltage, or sig- 
 naling power cannot be secured, the lights should then be oper- 
 ated from the charging generator, provision being made to 
 transfer the lights onto the interlocking battery in case of 
 failure of the generating unit. Attention is called to the 
 undesirability of lighting from this source unless either the 
 charging unit or interlocking battery is installed in duplicate, 
 since if only one generator and one battery were employed, 
 the capacity of the battery would have to be excessively 
 large to provide sufficient reserve against the failure of the 
 charging generator, such a failure in all probability being of 
 longer duration than would be the case with commercial 
 power. 
 
 PRECAUTIONS 
 
 In operating the lighting system from a charging generator 
 great care should be used to see that the normal voltage of the 
 lamj)s is never exceeded, since the bulbs will be quickly burnt 
 out if subjected to an excess voltage. This increased voltage 
 always exists when the charging generator is supplying cur- 
 rent for the lighting system at the same time it is charging the 
 interlocking battery; therefore, a regulating device must be 
 provided to maintain the voltage on the lamps at the normal 
 point. This device ordinarily is a hand operated rheostat 
 which has sufficient regulation to permit the voltage to be 
 kept at normal. It will be seen that the device will require 
 the maintainer's attention at frequent intervals; this, how- 
 ever, cannot be considered serious, as under such conditions 
 the interlocking battery would never be charged at night except 
 in case of emergency. Where duplicate batteries are employed, 
 a regulating device is not required, as the combination of 
 switches on the power board can be so arranged that it is 
 impossible to serve the lighting circuits from the battery 
 that is being charged. 
 
 Precaution respecting cross protection should be observed 
 whenever the interlocking battery may be called upon to 
 furnish current for the lighting system. At plants where the 
 operating switchboard is equipped with the cross protection 
 circuit breaker shown in Fig. 24 (both positive and negative 
 battery connections being broken through the circuit breaker 
 contacts), the signals can be electrically lighted from the inter- 
 locking battery without endangering the proper operation of 
 the switches, signals, or other functions of the plant. If, 
 however, it is proposed to electrically light the signals of an 
 existing G. R. S. plant at which plant the old type of circuit 
 breaker (Sec. 1, Elec. Int. Cat., page 280) is installed, it is 
 strongly recommended that the operating switchboard be 
 equipped with the double pole circuit breaker (Fig. 24) and 
 the circuits rearranged to embody the principles of the wiring 
 
130 GENERAL RAILWAY SIGNAL COMPANY 
 
 shown on page 88. The lighting mains under no condition 
 should be controlled through the circuit breaker. 
 
 RECOMMENDATIONS 
 
 It is recommended that two bulbs always be installed in 
 each signal lamp, burning in multiple or operated in connec- 
 tion with a "cut in" relay. 
 
 Regarding the source of power, it is recommended as good 
 practice that commercial power be employed, providing 
 arrangements are made to cut the lighting system onto the 
 interlocking battery in case of failure of the commercial source. 
 
 Where the interlocking plant is located in A. C. automatic 
 signal territory the lighting may be operated on any voltage 
 desired. At such a point high efficiency metallic filament 
 lamps can readily be operated. No reserve is necessary, in 
 view of the fact that the signal transmission line is always 
 thoroughly protected against power failure. 
 
 Where neither commercial power nor A. C. signaling current 
 is available, the signal lighting may be electrically operated 
 from the charging generator, providing the interlocking bat- 
 tery is (or batteries are) of sufficient capacity to insure the 
 continuous operation of the interlocking and lighting systems 
 through any period of time necessary to repair a failure on the 
 part of the charging unit. 
 
 In all cases where storage batteries may be called upon to 
 furnish current for the lighting circuits, regulating apparatus 
 must be installed to permit the current from such battery to 
 be delivered to the lighting mains at normal voltage during a 
 charging period. 
 
 Whenever the interlocking battery serves as a reserve, the 
 circuits and apparatus on the operating switchboard must be 
 such that operation of the lighting system will in no way 
 endanger cross protection. 
 
SECTION V 
 
 ELECTRIC LOCKING AND CHECK LOCKING 
 
 GIVING A DESCRIPTION OF THE VARI- 
 OUS TYPES OF CIRCUITS AND THEIR 
 APPLICATION TO ELECTRIC INTER- 
 LOCKING WORK 
 
 
E 
 
 ELECTRIC LOCKING 
 
 LECTRIC locking as defined by the Railway Signal Asso- 
 ciation consists of "the combination of one or more elec- 
 tric locks and controlling circuits by means of which 
 levers in an interlocking machine, or switches or other devices 
 operated in connection with signaling and interlocking, are 
 secured against operation under certain conditions." 
 
 Electric locking is a development of the tendency in rail- 
 way signaling practice to constantly decrease the manual 
 control of all functions and to increase the automatic control. 
 The first important step along this line was the operation of 
 switches and signals through the medium of interlocked levers 
 concentrated in a central machine. The real beginning of 
 electric locking, however, was in the installation at mechani- 
 cal plants of locking circuits which were to prevent the lever- 
 man from changing the route in the face of an approaching 
 train. This was followed by a step which had its inception in 
 the all-electric interlocking system : namely, section or detector 
 locking which was designed to afford safety to a train from 
 the time it passed the home signal location until it cleared 
 the limits of the interlocking plant. As first installed in con- 
 nection with electric interlocking, the switches and derails in 
 a given track section were prevented from being thrown while 
 a train was on that track section, by interrupting the current 
 supply to those functions by means of a relay controlled by 
 the track relay of the section in question. At the present 
 time this method of control is not generally used with the 
 all-electric system, having given way to the practice of equip- 
 ping each switch and derail lever with electric locks, properly 
 controlled by the various track sections. 
 
 Ever since the time of those first successful installations, 
 the signal men of the country have become more and more 
 alive to the fact that safety of railway operation could be 
 much further assured by the development of this principle of 
 automatically preventing the operation of functions which 
 might endanger the safety of trains approaching or passing 
 through interlocking plants. In fact, at the present time 
 electric locking has come to be considered by many a necessary 
 adjunct to an interlocking plant. 
 
 Due to the rapidity of the development of the art, a wide 
 range of methods has been used to accomplish the same 
 result; the principles involved, nevertheless, have been so 
 nearly uniform that it has become possible to determine the 
 elements that enter into good practice. For instance, it will 
 be found that it should always be possible to restore the home 
 signal to the normal position, even though it may not be 
 desirable to release the route beyond. Also in case of emerg- 
 ency, release of the route is generally permitted through the 
 use of a time release or hand switch; the circuits are such 
 that when the device has been operated to secure the desired 
 
134 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 96. ELECTRIC TIME RELEASE 
 
 release, some circuit essential to the operation of either switch 
 or signal functions will be broken, thus necessitating that the 
 time release or hand switch be returned to its normal position 
 before operation of the switches or signals affected can be 
 resumed. 
 
 Based on the above, the Railway Signal Association has 
 classified Electric Locking in the following manner: 
 "SECTION LOCKING. Electric locking effective while a train 
 occupies a given section of a route and adapted to prevent 
 manipulation of levers that would endanger the train while 
 it is within that section." 
 
 An illustration of section locking is given in Fig. 97, showing 
 the manner of controlling the locks with which the switch 
 levers are equipped. As the levers are locked in either the 
 full normal or full reverse position, it will be seen that the 
 
 ./O^ 1 ^*" f i -^i U* 
 
 ^ 7i t Z^C 
 
 on Achievers 
 
 FIG. 97. SECTION LOCKING CIRCUIT 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 135 
 
 operator is prevented from changing the position of the switches 
 or derails in a given section during such time as that section 
 is occupied or fouled by a train. 
 
 " ROUTE LOCKING. Electric locking taking effect when a train 
 passes a signal and adapted to prevent manipulation of levers 
 that would endanger the train while it is within the limits 
 of the route entered." 
 
 Route locking is a development of section locking in which 
 the switches and derails in all sections of any route are locked 
 
 \l 
 
 Repeating 
 relay for 
 Section IZT 
 
 Full normal and 
 reverse lock on 
 switch lever ' 1 1 
 
 Repeating 
 relay for - 
 Section UT + 
 
 Full normal and 
 reverse lock on 
 switch lever 14 
 
 FIG. 98. ROUTE LOCKING CIRCUIT 
 
 NOTE. To positive battery through lever contacts and relays as de- 
 termined by the layout of track indicated by dotted lines. 
 
 from the time a train enters that route until such time as the 
 route is cleared. An illustration of route locking applied to 
 a simple layout is shown in Fig. 98. It is evident that the 
 circuits become somewhat complicated when used in connec- 
 tion with an interlocking where the routing of each signal 
 may extend over a number of combinations of track sections. 
 "SECTIONAL ROUTE LOCKING. Route locking so arranged that 
 a train, in clearing each section of the route, releases the locking 
 affecting that section." 
 
 This is a further development of section locking in which 
 the functions in all sections in a given route are locked as 
 
136 GENERAL RAILWAY SIGNAL COMPANY 
 
 soon as the train has passed the home signal, the functions in 
 each section, however, being released behind the train as soon 
 as the train has passed out of the section. 
 
 The installation of sectional route locking has been largely 
 restricted to points such as congested terminals where the 
 maximum number of traffic movements is demanded with a 
 maximum of protection. Due to its being little used, and on 
 account of the rather complicated circuits involved, no at- 
 tempt has been made to show any typical illustration of the 
 circuits required in such work. 
 
 Control 5ig.6 
 
 " Half reverse lock 
 
 Screw Release * on 5ign<al lever 6 
 
 FIQ. 99. APPROACH LOCKING CIRCUIT 
 
 "APPROACH LOCKING. Electric locking effective while a train 
 is approaching a signal that has been set for it to proceed and 
 adapted to prevent manipulation of levers or devices that 
 would endanger that train." 
 
 Fig. 99 shows an approach locking circuit in which a half 
 reverse lock on the home signal lever, through the medium of 
 the locking between the signal and switch levers, prevents the 
 release of the route during such time as the lock is de-energized. 
 The locking becomes effective after the signal for the route has 
 been cleared and the train has passed a predetermined point, 
 which in Fig. 99 is the annunciator section; the locking is 
 released as soon as the train passes the home signal. 
 
 It will be noted that in Fig. 99 no protection is given after 
 the train has passed the home signal, i. e. no route locking 
 protection is afforded. Protection can be given through the 
 plant by releasing the signal lever in the first section beyond 
 the limits of the plant instead of on the forty-five degree 
 control relay. 
 
ELECTRIC INTERLOCKING HANDBOOK 137 
 
 "STICK LOCKING. Electric locking taking effect upon the 
 setting of a signal for a train to proceed, released by a passing 
 train, and adapted to prevent manipulation of levers that 
 would endanger an approaching train." 
 
 Stick locking in reality is only another form of approach 
 locking, being different in that it becomes effectve on the 
 reversal of the home signal lever and does not further depend 
 on the approach of a train. 
 
 Fig. 100 shows a stick locking circuit in which the half reverse 
 lock, with which the signal lever is equipped, prevents its 
 return to the full normal position, and, therefore, the release 
 of the route governed, until such time as a train has passed on 
 to the release section ; this section is shown located beyond the 
 interlocking limits as mentioned under "Approach Locking." 
 
 L . 
 
 Ir" li 
 
 Screw Relea 
 Control 
 
 FIG. 100. STICK LOCKING CIRCUIT 
 
 It will be seen that it is necessary to restore the signal lever to 
 the normal position while the train is on the releasing section, 
 otherwise the signal lever can only be returned to the full 
 normal position through the operation of the time release. 
 If desired, the releasing section may be extended to include 
 the several track sections in the route so that the lever may 
 be restored to the normal position any time the train is within 
 the limits of the route. 
 
 "INDICATION LOCKING. Electric locking adapted to prevent 
 any manipulation of levers that would bring about an unsafe 
 condition in case a signal, switch, or other operated device fails 
 to make a movement corresponding with that of the operating 
 lever ; or adapted directly to prevent the operation of one de- 
 vice in case another device, to be operated first, fails to make 
 the required movement." 
 
 As an illustration of this type of locking may be taken 
 any electrical device, which is designed to indicate the cor- 
 respondence of position between a unit and its controlling 
 
138 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 lever. The simplest example is the indication of the position 
 of a semaphore blade by means of a lock or other device on 
 the governing lever, the control of this lock being carried 
 through the circuit breaker on the signal. The well-known 
 dynamic indication of the all-electric system is a striking 
 example of indication locking. 
 
 It will be found that with the exception of certain forms of 
 indication locking, such as the dynamic indication, the differ- 
 ent basic forms of electric locking as outlined above are seldom 
 used alone, but in combinations. 
 
 TK 
 
 M2' 
 
 ^d_T j[ Annunciator 
 
 Screw Release f 
 
 Full Normal and Reverse 
 lochs on Switch Levers. 
 
 FIG. 101. CIRCUITS FOR COMBINATION OF APPROACH, INDICATION 
 AND SECTION LOCKING 
 
 Fig. 101 illustrates the use of an approach locking circuit in 
 conjunction with section locking, and with indication locking 
 for distant signal No. 1. In this circuit the control is secured 
 by equipping the switch levers with electric locks governed by 
 a stick relay. The locking becomes effective when signal 
 No. 6 is cleared but is capable of being released by the return 
 of lever No. 6 to the normal position, providing a train has 
 passed into the releasing section, or providing no train is on 
 any of the track sections repeated by the annunciator and 
 the forty-five degree control relay for signal No. 6. This 
 circuit does not require that the lever be returned to the 
 normal position while the train is on the releasing section. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 139 
 
 If this feature is desired the control may be broken through 
 the contacts on lever No. 6 instead of through the circuit 
 breaker of the signal. 
 
 The indication locking feature consists of carrying the 
 control of the stick relay through the circuit breaker of dis- 
 tant signal No. 1 to prevent release of the route under any 
 condition if signal No. 1 is not in the caution or stop position. 
 
 Fig. 102 illustrates a similar arrangement of tracks and sig- 
 nals, with circuits providing stick locking, section locking, and 
 indication locking. It is to be noted that in every particular 
 
 ^^ 
 
 rae ^i 
 10 -IF i ^ ? 
 
 Stick Relay 
 
 Full Normal and Reverse 
 locks on Switch Levers 
 
 FIG. 102. CIRCUIT FOR COMBINATION OF STICK, INDICATION AND 
 SECTION LOCKING 
 
 this circuit is the same as that in Fig. 101, except that the stick 
 relay does not have a pick up through the forty-five 
 degree control relay and the annunciator in series; the 
 omission of this wire classes the circuit under "Stick Locking." 
 The locking becomes effective upon the clearing of signal 
 No. 6 and is released by a train on the clearing section or by 
 operation of the time release. 
 
CHECK LOCKING 
 
 WHEN interlocking plants are located a comparatively 
 short distance apart, it is advisable and frequently 
 necessary to install what is known as "Check Lock- 
 ing," which enforces cooperation between the levermen at the 
 two plants in such a manner as to prevent opposing signals, 
 governing over the same track, from being at proceed at the 
 same time. Furthermore, after a signal has been cleared and 
 accepted by a train, check locking prevents an opposing signal 
 at the adjacent interlocking plant from being cleared until the 
 train has passed through to that plant. 
 
 Fig. 103 shows a check locking circuit which involves the 
 use of check lock levers at each plant, the arrangement and 
 method of operation of these levers making the circuit especially 
 
 z Q 
 
 RgQ . 
 
 FIG. 103. CHECK LOCKING CIRCUIT 
 For use where there is no preference as to direction cf traffic. 
 
 adaptable where there is no preference as to the direction of 
 traffic. The signal levers at each station, governing move- 
 ments over the intervening track, are so interlocked with the 
 check lock levers in their respective machines, that they may 
 not be moved from their full normal position until their re- 
 spective check lock levers have been moved to the full reverse 
 position. By reference to Fig. 103 it will be seen that the 
 check lock levers are so controlled that but one of them can 
 be in the full reverse position at the same time. Therefore, 
 it is impossible for signals No. 1 and No. 20 at stations A and 
 Z, respectively, to be displayed at proceed at the same time. 
 
 The control circuit for the check lock levers is shown broken 
 through relay X, which represents the track relays for the 
 sections between signals No. 1 and No. 20. This prevents a 
 check lock lever being thrown to the full reverse position 
 and, consequently, any traffic movement from being made 
 during such time as these sections are occupied. The release 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 141 
 
 of either lever in moving to the reverse position is effected 
 by current taken from the battery at the far end of the circuit. 
 
 The check locking circuit shown in Fig. 104 is designed for 
 operation when there is a preference in the direction of traffic, 
 since traffic movements can normally be made from A to Z 
 without any interference from the check locking, it being 
 necessary, however, when making a movement from Z to A 
 (against traffic) to operate both check lock levers. 
 
 Each station is equipped with a check lock lever so interlocked 
 with signal levers No. 1 and No. 20, that lever No. 1 is 
 free to be moved only when the check lock lever at A is full 
 normal, and lever No. 20 only when the check lock lever 
 at Z is full reverse. The control, however, of the check 
 lock levers is such that the lever at Z can be reversed only 
 
 II., z Q IL- 
 
 KXCATKM, MAMCT 
 
 FIG. 104. CHECK LOCKING CIRCUIT 
 For use where there is preference as to direction of traffic. 
 
 after the check lock lever at A has been thrown to the full 
 reverse position, and, after having been moved from its normal 
 position, the lever at A can be returned to the full normal 
 position only after the return of the check lock lever at Z to 
 full normal. Thus it will be seen that it is impossible to have 
 a condition existing which would permit signal levers No. 1 
 and No. 20 to be reversed at the same time. 
 
 The final movement of the check lock lever at Z in being 
 moved to the full reverse position, and of the check lock lever 
 at A in being placed normal, is permitted by energy secured 
 from the battery located at the far end of the circuit. 
 
SECTION VI 
 
 INSTALLATION AND OPERATING DATA FOR 
 POWER PLANTS AND SWITCHBOARDS 
 
 COVERING LEAD TYPE STORAGE BAT- 
 TERIES, GENERATORS AND MOTOR 
 GENERATORS, GASOLINE ENGINES AND 
 SWITCHBOARDS, WITH DATA AND 
 TABLES FOR THE DETERMINATION OF 
 THE PROPER TYPE AND CAPACITIES 
 OF APPARATUS 
 
LEAD TYPE STORAGE BATTERIES 
 
 STORAGE or secondary; batteries consist of cells, the plates 
 and electrolyte of which can be restored to their original 
 condition after discharge, by forcing an electric current 
 through the cell in the direction opposite to that taken by 
 the current produced by the cell. When a primary battery 
 is exhausted the electrolyte and elements are renewed before 
 further use. It is in this reversability or regeneration that 
 lies the fundamental difference between storage and primary 
 cells. 
 
 The lead type storage cell consists essentially of two 
 plates or sets of plates suspended in a dilute solution of sul- 
 phuric acid. There are many forms of plate construction, but 
 the chemical composition is generally the same, the positive 
 and negative plates being made of peroxide of lead and pure 
 
 FIG. 105 LEAD TYPE STORAGE BATTERY AND BATTERY RACK 
 
 or "sponge" lead, respectively. When the elements are com- 
 posed of more than two plates the negative plates in each 
 cell are one more in number than the positives. Wooden 
 or hard rubber separators are introduced between the plates 
 to prevent any of the positives from coming into contact with 
 the negative plates, thus causing short circuit. 
 
 When the circuit is closed and the battery discharging, the 
 sulphuric acid combines with the lead in the elements forming 
 a deposit of sulphate of lead on the surface of both positive 
 and negative plates, the density (specific gravity) of the 
 electrolyte diminishing as the sulphuric acid leaves it to com- 
 bine with the materials of the plates. By forcing current 
 through the cell in the direction opposite to that of the dis- 
 charged current, the sulphate of lead on the negative plates 
 will be converted into sponge lead and sulphuric acid, and the 
 sulphate of lead in the positive plates into peroxide of lead 
 and sulphuric acid ; the sponge lead and the peroxide of lead 
 remain in the plates and the sulphuric acid diffuses in the 
 electrolyte, the specific gravity of which rises in consequence. 
 
146 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 
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ELECTRIC INTERLOCKING HANDBOOK 147 
 
 EXTRACT FROM R. S. A. SPECIFICATIONS FOR 
 LEAD TYPE STATIONARY STORAGE BAT- 
 TERY FOR INTERLOCKINGS (1913) 
 
 1. INTENT 
 
 The intent of these specifications is to provide for the 
 furnishing of complete storage battery cells and parts, 
 designed to be located in interlocking stations or battery- 
 houses and used for operating interlocking and signal 
 apparatus. 
 
 2. DESIGNATIONS 
 
 (a) In ordering cells or parts the nominal capacity re- 
 quired will be designated as "40 A. H., "80 A. H.," "120 
 A. H.," "200 A. H.," "320 A. H.," or "400 A. H.," and 
 these terms shall be understood to signify, on an eight (8) 
 hour basis, the capacities and dimensions thus designated 
 in these specifications and Railway Signal Association 
 drawing 1224. (See page 146.) 
 
 (b) Each complete cell, unless otherwise specified, is 
 understood to include the following parts : 
 
 1. One (1) positive group, consisting of the neces- 
 sary number of positive plates assembled with con- 
 necting strap and one (1) connecting bolt. 
 
 2. One (1) negative group, consisting of the neces- 
 sary number of negative plates assembled with con- 
 necting strap and one (1) connecting bolt. 
 
 3. One (1) set of separators, with dowels and hold 
 downs. 
 
 4. One (1) glass jar. 
 
 5. One (1) glass sand tray, with moulded feet. 
 
 6. One (1) glass cell cover. 
 
 7. Required electrolyte. 
 
 (c) Positive or negative groups, if ordered separately, 
 will be ready for service after an initial charge continued 
 for fifty (50) to sixty (60) hours at the eight (8) hour rate. 
 
 3. CAPACITY OP BATTERY 
 
 In conformity with service requirements. 
 
 4. NUMBER OP CELLS PER BATTERY 
 
 In conformity with voltage requirements. 
 
 5. DIMENSIONS 
 
 Jars, sand trays and covers must conform to Railway 
 Signal Association drawing 1224, which is an essential 
 part of these specifications. (See page 146.) 
 
 6. ELEMENTS 
 
 (a) Positive plates shall be of the Plante type. 
 
148 GENERAL RAILWAY SIGNAL COMPANY 
 
 (&) Negative plates shall be either of the Plante type or 
 of the type having mechanically applied active material. 
 
 (c) Positive and negative plates shall be respectively 
 connected into positive and negative groups by burning to 
 lead straps. 
 
 7. SEPARATORS 
 
 Separators shall be of specially treated wood. 
 
 8. ELECTROLYTE 
 
 (a) Electrolyte shall have a specific gravity of between 
 1.205 and 1.215 at the end of the initial charge in service. 
 
 (6) Electrolyte shall be in accordance with Railway 
 Signal Association specifications. 
 
 9. ACCEPTANCE 
 
 No unit or part will be accepted which does not, in the 
 judgment of the Purchaser, conform to the best practice 
 with respect to material and workmanship. 
 
 10. SERVICE REQUIREMENTS 
 
 (a) It is essential that all parts shall be rugged in the 
 highest degree both mechanically and electrically. The 
 apparatus furnished must give satisfactory and economical 
 service. 
 
 (6) Should any injurious buckling of plates occur in 
 normal service within one (1) year after delivery, or 
 should the capacity of any cell or element fall to less than 
 eighty-five (85) per cent, of the specified capacity at the 
 eight (8) A. H. rate, in normal service, within one (1) 
 year after delivery, the Contractor must replace the 
 defective parts and restore the affected cells to their full 
 specified capacity and to a condition satisfactory to the 
 Purchaser, without additional cost to him. 
 
 (c) As far as practicable, it is understood that the cells 
 are to be operated in the manner recommended by the 
 Contractor, but the necessities of operation must be the 
 first consideration. 
 
 R. S. A. DIRECTIONS FOR INSTALLATION OF 
 LEAD TYPE STATIONARY STORAGE 
 
 BATTERIES (1909) 
 1. GENERAL 
 
 (a) The battery should be housed in a space by itself as 
 the acid fumes given off during the charge are of a cor- 
 rosive nature. This space should be well ventilated, 
 well lighted, and as dry as possible. If the space is speci- 
 ally constructed it should contain no metal work other 
 than lead. If this is not possible, then such metal parts 
 
ELECTRIC INTERLOCKING HANDBOOK 149 
 
 should be protected by at least two (2) coats of acid-proof 
 paint. The floors of a large battery room should be 
 preferably of vitrified brick, jointed with pitch. 
 
 (6) Batteries should be placed in a room having a uni- 
 form temperature, preferably seventy (70) degrees Fahr. 
 Low temperature does not injure a battery, but lowers its 
 capacity approximately one-half (%) of one per cent, per 
 degree. Excessively high temperatures shorten the life of 
 the plates. 
 
 (c) If glass jars are used and cell is not of the two-plate 
 type, the following should be observed : 
 
 1. Batteries up to four hundred (400) ampere hour 
 capacity shall be placed in glass jars. 
 
 2. The capacity of batteries shall 'be for an eight 
 (8) hour rate of discharge at seventy (70) degrees Fanr. 
 
 3. Batteries having a large number of cells, such as 
 at interlocking plants, shall be provided with sub- 
 stantial wood racks to support them. These racks shall 
 preferably be made of long-leaf yellow pine with non- 
 corrosive fastenings, and thoroughly protected by at 
 least two (2) coats of acid-proof paint. Cells shall be 
 arranged transversely, and the layouts be such that 
 each cell is accessible for inspection and provide suf- 
 ficient head room over each cell to remove the element 
 without moving the jar. 
 
 4. Each jar shall be set in a tray which has been 
 evenly filled with fine dry bar sand, the trays resting on 
 suitable insulators. 
 
 5. When placing the positive and negative groups 
 into the jars see that the direction of the lug is rela- 
 tively the same in each case, so that a positive lug of 
 one (1) cell adjoins and is connected to a negative lug of 
 the next cell throughput the battery, thereby giving 
 proper polarity, providing a positive lug at one free end 
 and a negative at the other. 
 
 6. Before bolting the battery lugs together, they 
 should be well scraped at the point of contact, to insure 
 good conductivity and low resistance in the circuit. The 
 connector studs should be covered with vaseline before 
 screwing up, and all connections covered with vaseline 
 or suitable paint. 
 
 7. Before putting electrolyte in the battery the cir- 
 cuits connecting same with the charging source must be 
 completed, care being taken to have the positive pole of 
 the charging source connected with the positive end of 
 the battery and the negative poles. The electrolyte 
 should cover the top of plates by one-half (%) inch. 
 
 2. ELECTROLYTE 
 
 (a) The electrolyte must be free from impurities and 
 meet the tests prescribed by the Railway Signal Association. 
 
150 GENERAL RAILWAY SIGNAL COMPANY 
 
 INITIAL CHARGE 
 
 (a) The initial charge must follow the Manufacturer's 
 instructions. The charge should be started promptly as 
 soon as all the cells are filled with electrolyte, and all con- 
 nections made, usually at the normal rate, and continued 
 at the same rate until both the specific gravity and voltage 
 show no rise over a period of ten (10) hours, and gas is 
 being freely given off from all the plates. The positive 
 plates will sometimes gas before the negatives. Gen- 
 erally, to meet these conditions, from forty-five (45) to 
 fifty-five (55) hours continuous charging at the normal 
 rate will be required; and if the rate is less, the time 
 required will be proportionately increased. In case the 
 charge is interrupted, particularly during its earlier stages, 
 or if it is not started as soon as the electrolyte is in the 
 cells, the total charge required (in ampere hours) will be 
 greater than if the charge is continued and is started at once. 
 
 (6) As a guide in following the progress of the charge, 
 readings should be regularly taken and recorded. The 
 gassing should also be watched, and if any cells are not 
 gassing as much as the adjoining cells, they should be 
 carefully examined and the cause of the trouble removed. 
 The temperature of the electrolyte should be closely 
 watched, and if it approaches one hundred (100) degrees 
 Fahr. the charging rate must be reduced or the charge 
 temporarily stopped until the temperature lowers. 
 
 (c) The specific gravity will fall after the electrolyte is 
 added to the cells, and will then gradually rise as the 
 charge progresses, until it is up to 1.210 or thereabout. 
 
 (d) The voltage of each cell at the end of the charge 
 will have risen to its maximum and usually will be be- 
 tween two and five-tenths (2.5) and two and seven-tenths 
 (2.7) volts. 
 
 (e) If the specific gravity of any of the cells at the com- 
 pletion of the charge is below 1.205, or above 1.215, allow- 
 ance being made for the temperature correction, it should 
 be adjusted to within these limits, by removing and adding 
 electrolyte if the specific gravity is low, and adding chemi- 
 cally pure water if the specific gravity is high, to again 
 bring the surface at the proper height above the top of 
 the plates. It is of the utmost importance that the 
 initial charge be complete in every respect. 
 
 (/) In case of batteries charging from primary cells, if 
 possible, the initial charge should be given at a place 
 where direct current is available of sufficient voltage to 
 complete the charge at the normal rate, the cells being 
 then transferred to their permanent position. 
 
 TWO-PLATE CELLS 
 
 The general method of installation is the same as the 
 above with the following exceptions: Each cell contains 
 
ELECTRIC INTERLOCKING HANDBOOK 151 
 
 one positive and one negative plate, the positive of one 
 cell being solidly connected by a lead strap to the nega- 
 tive plate of the adjoining cell, and consequently no con- 
 nectors are required. At the ends of each row there is 
 one (1) free positive plate and one (1) free negative plate 
 respectively, which constitute the positive and negative 
 terminals of that row. Connections to these terminals are 
 made with bolt connectors. 
 
 5. LARGE CAPACITY CELLS 
 
 (a) Batteries of a greater capacity than four hundred 
 (400) ampere hours shall be placed in wood tanks and shall 
 be covered by special specifications. 
 
 (6) Where tanks are used, it is customary to support 
 them on a double tier of glass insulators. 
 
 (c) Plates are shipped separately and assembled one at 
 a time in the tank and burned solidly to a heavy lead bus 
 bar by means of a hydrogen flame. It is recommended 
 that when installations of this kind are required that 
 battery Manufacturers install the battery in accordance 
 with tneir standard practice. 
 
 R. S. A. INSTRUCTIONS FOR OPERATION OF LEAD 
 TYPE STORAGE BATTERIES AT INTER- 
 LOCKING PLANTS (1909) 
 
 1. BATTERY 
 
 batteries ; cells each ; type ; number of 
 
 plates per cell normal charging rate amperes. 
 
 batteries; cells each; type ; number of 
 
 plates per cell normal charging rate amperes. 
 
 2. PILOT CELL 
 
 In each battery, select a readily accessible cell, to be 
 used in following the daily operation of the battery, by 
 taking specific gravity readings of the electrolyte, as 
 given below. Keep the level of the electrolyte of this cell 
 at a fixed height, one-half ( x /2) inch above the top of the 
 plates, by adding a small quantity of chemically pure 
 water each day; THIS is EXTREMELY IMPORTANT. 
 
 3. CHARGING 
 
 (a) When to charge. 
 
 1. As a general rule, do not charge until the specific 
 gravity of the pilot cell has fallen at least ten (10) points 
 below the preceding overcharge maximum, the battery 
 being then about one-third (Vs) discharged. 
 
 2. In any case, charge as soon as possible after reach- 
 ing either of the limits given below under "Discharging," 
 or if for any reason a heavy discharge is expected. 
 
152 GENERAL RAILWAY SIGNAL COMPANY 
 
 (6) Regular charge. 
 
 1. Charge at normal rate of ........ amperes, or as 
 
 near as possible, and continue until the specific gravity of 
 the pilot cell has risen to three (3) points below the maxi- 
 mum reached on the preceding overcharge, WHEN THE 
 CHARGE SHOULD BE STOPPED : for example, if the maxi- 
 mum specific gravity on the overcharge is 1.207, the spe- 
 cific gravity reached on regular charge should be 1.204. 
 
 2. The cells should all be gassing moderately. 
 
 (c) Overcharge. 
 
 1. Once every two (2) weeks, on .................. 
 
 prolong the regular charge until fifteen (15) minute read- 
 ings of the specific gravity of the pilot cell and of the 
 battery voltage, taken from the time the cells commence 
 to gas show no rise on five (5) successive readings, thus 
 having been at a maximum for one hour. 
 
 2. When the above method of overcharge is not prac- 
 ticable, the overcharge may be given every sixth charge, 
 provided the battery receives an overcharge at least once 
 every month. If in following this method, i. e., where 
 the overcharge is given at intervals longer than two (2) 
 weeks and not less frequently than once a month, the 
 regular charge should be prolonged until one-half (2) 
 hour readings of the specific gravity of the pilot cell and 
 of the battery voltage, taken from the time trie cells begin 
 to gas, show no rise on seven (7) successive readings, thus 
 having been at the maximum for three (3) hours. 
 
 3. The cells should all be gassing freely. 
 
 4. The overcharge should be given whether the bat- 
 tery has been in regular use or not. 
 
 (d) Charging in series. 
 
 If two (2) or more batteries are charged together, in 
 series, care should be taken that each battery is cut out 
 when fully charged ; in other words, if one of the batteries 
 discharges less than the other it should not receive the 
 same charge. 
 
 4. DISCHARGING 
 
 (a) Never allow the specific gravity of the pilot cell to 
 fall more than about thirty (30) points below the preceding 
 overcharge maximum. As a rule, do not allow specific 
 gravity to fall more than twenty (20) points. 
 
 (6) Never allow the voltage to go below ONE AND 
 
 EIGHTY-FIVE ONE-HUNDREDTH3 (1.85) VOLTS PER CELL 
 
 when discharging at the normal rate ( .......... amperes). 
 
 If the rate of discharge is less than the normal rate, the 
 voltage should not be allowed to go so low. 
 
 Limiting voltage .......... cells .......... volts. 
 
 Limiting voltage .......... cells .......... volts. 
 
 (c) Never allow the battery to stand in a compktely 
 discharged condition. 
 
ELECTRIC INTERLOCKING HANDBOOK 153 
 
 5. READINGS 
 
 (a) Read and record the specific gravity of the pilot cell 
 and battery voltage just before starting and ending every 
 charge, together with the temperature of the electrolyte. 
 
 (6) To properly compare the specific gravity readings, 
 they should be corrected to standard temperature (seventy 
 (70) degrees Fahr.) by adding one (1) point for every 
 three (3) degrees above, and subtracting one (1) point for 
 every three (3) degrees below standard temperature. 
 
 (c) Once every two (2) weeks, after the end of the 
 charge preceding the overcharge, read and record the 
 gravity of each cell in the battery. 
 
 6. INSPECTION 
 
 (a) Carefully inspect each cell on the day before the 
 overcharge, using a lamp on an extension cord for the 
 purpose. Examine between the plates and hanging lugs 
 to make sure that they are not touching, and also make a 
 careful note of any peculiarity in color, etc., of the plates. 
 
 (6) Use a strip of wood or hard rubber in removing 
 short circuits. NEVER USE METAL. 
 
 (c) Toward end of the charge preceding the overcharge, 
 note any irregularity of gassing; cells gassing slowly 
 should be investigated. 
 
 7. INDICATIONS OF TROUBLE 
 
 (a) FALLING OFF IN SPECIFIC GRAVITY OR VOLTAGE 
 relative to the rest of the cells. 
 
 (6) LACK OF OR SLOWER GASSING on overcharge, as 
 compared with adjoining cells. 
 
 (c) COLOR OF PLATES markedly lighter or darker than 
 in adjoining cells, except that sides of plates facing glass, 
 may vary considerably. 
 
 (d) In case of any of the above symptoms being found, 
 examine carefully for cause, and REMOVE AT ONCE. 
 
 (e) Report trouble of any description at once to 
 
 8. BROKEN JARS 
 
 If a jar should break, and there is no other to take its 
 place, so that the plates will have to remain out of serv- 
 ice for some time, keep the negatives covered with water 
 and allow the positives to dry. Connect into circuit again 
 lust before a charge, so that the plates will receive the 
 benefit of the charge. 
 
 9. OTHER IMPORTANT POINTS 
 
 (a) Plates must always be kept COVERED WITH ELECTRO- 
 LYTE. 
 
 (V) Use only CHEMICALLY PURE WATER, preferably dis- 
 tilled, to replace evaporation. 
 
154 GENERAL RAILWAY SIGNAL COMPANY 
 
 (c) NEVER ADD ELECTROLYTE EXCEPT under the condi- 
 tions explained above. 
 
 (d) Never allow the SEDIMENT to get to the bottom of 
 the plates; remove sediment when the clearance has 
 reached one-half (MO inch. 
 
 (e) VENTILATE the room freely, especially when charging. 
 (/) Never bring an EXPOSED FLAME near the battery 
 
 when charging. 
 
 (0) NEVER ALLOW METALS OR IMPURITIES of any kind to 
 get into the cells; if this happens, remove and wash the 
 plates and renew the electrolyte. 
 
 (h) Fill out the report sheets regularly. 
 
 (1) READ THE GENERAL INSTRUCTIONS CAREFULLY. 
 
 REQUIRED CAPACITY OF STORAGE BATTERIES 
 
 USED WITH G. R. S. ELECTRIC 
 
 INTERLOCKING 
 
 A storage battery of fifty-five to fifty-seven cells, having 
 an approximate potential of 110 volts, is used in connection 
 with G. R. S. electric interlocking installations. The required 
 ampere hour capacity is dependent on a number of variables, 
 viz : the number of days between charges, frequency of lever 
 movements, amount of current required for lighting, for cut- 
 outs, indicators, annunciators, etc., and the number of days 
 of reserve power desired. 
 
 A separate low voltage battery is generally installed when 
 there are a number of locks, indicators, relays, etc., required 
 at the plant, as this type of device is more efficient and can 
 have a more rugged magnet winding when designed for opera- 
 tion on a potential of 10 or 20 volts; furthermore, there are 
 certain safety features which can be secured in connection 
 with this low voltage control. The capacity of such a low 
 voltage battery is determined in the same manner as the high 
 voltage battery, as given hereafter. 
 
 The following instructions will enable the determination, 
 with reasonable accuracy, of the ampere hour capacity of the 
 battery required for use with a G. R. S. electric interlocking 
 plant. 
 
 AMPERE HOUR CAPACITY REQUIRED FOR OPERATION OF 
 FUNCTIONS (See also table on page 158.) 
 
 The ampere hour capacity required for the operation of 
 functions is obtained by multiplying the number of lever 
 movements per day by the number of days between charges 
 and by a "Function Constant." This constant, to be obtained 
 by reference to table on page 155, is influenced mainly by two 
 things: the average length of time that signals are held in 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 155 
 
 the proceed position and the ratio of the number of signal 
 movements to switch movements. In the absence of definite 
 information on these points it is suggested that the constant 
 .006 be used as representing a fair average condition. This 
 constant is shown underlined in the table. 
 
 By reference to the table of Function Constants it can be 
 easily seen that it is advisable to keep down the length of 
 time signals are held in the proceed position, a glance indicat- 
 ing that the battery capacity will run up very rapidly as the 
 time of holding signals at proceed increases. In this connec- 
 tion it may be stated that there have been cases where a much 
 smaller size battery has been permitted due to the saving in 
 
 TABLE OF FUNCTION CONSTANTS 
 
 Average Length of Time Signals are 
 Held in Proceed Position 
 Minutes 
 
 Ratio of Signal to Switch Movements 
 
 1-2 
 
 1-3 
 
 1-4 
 
 1-5 
 
 2 
 
 .006 
 
 .005 
 
 .005 
 
 .005 
 
 3 
 
 .007 
 
 .006 
 
 .006 
 
 .006 
 
 5 
 
 .010 
 
 .008 
 
 .007 
 
 .007 
 
 10 
 
 .016 
 
 .013 
 
 .011 
 
 .010 
 
 15 
 
 .022 
 
 .017 
 
 .015 
 
 .013 
 
 30 
 
 .041 
 
 .032 
 
 .026 
 
 .023 
 
 hold clear current, this being effected by the installation of 
 annunciators, which by suitably indicating the approach of 
 a train reduces the length of time of holding the signals at 
 proceed. Furthermore, it is interesting to note that the saving 
 effected by the installation of this smaller battery may more 
 than balance the cost of such annunciator installation. 
 
 AMPERE HOURS REQUIRED FOR OPERATING 
 SWITCHBOARD CUT-OUTS 
 
 In every G. R. S. electric interlocking plant one or more 
 circuit breaker cut-outs are required for cross protection pur- 
 poses. The capacity required for cut-outs is obtained by 
 multiplying the number of cut-outs by nine-tenths and by 
 the number of days between charges. A discussion as to the 
 number of cut-outs to be employed to suitably sectionalize a 
 plant is given on page 93. 
 
 AMPERE HOURS REQUIRED FOR ELECTRIC LIGHTING 
 (See page 127.) 
 
 When the signals at an interlocking plant are to be lighted 
 by electricity, the interlocking battery is generally held as a 
 reserve against the failure of the normal source of power. 
 The number of days which the battery may be called upon to 
 
156 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 furnish current in such an event depends upon the probable 
 length of time required to repair any derangement of the 
 apparatus normally furnishing power to the lighting system. 
 The ampere hour capacity which must be provided for the 
 lighting is, therefore, determined by multiplying the ampere 
 hours per signal per day by the number of signals to be lighted 
 and the number of days' operation which may be required 
 between charging periods. 
 
 TABLE OF AMPERE HOURS PER DAY PER SIGNAL. 110 VOLT 
 
 CARBON FILAMENT BULBS TWO BULBS PER SIGNAL, 
 
 CONNECTED IN MULTIPLE 
 
 Candle Power 
 per Bulb 
 
 AVERAGE NUMBER OF HOURS LIGHTS ARE BURNED 
 PER DAY 
 
 12 
 
 13 U 
 
 Ampere Hours 
 
 Ampere Hours 
 
 Ampere Hours 
 
 2 
 4 
 
 2.18 
 4.36 
 
 2.36 
 4.72 
 
 2.55 
 5.09 
 
 NOTE. Values approximate. 
 
 AMPERE HOURS REQUIRED FOR MISCELLANEOUS 
 PURPOSES 
 
 When auxiliary devices, such as indicators, locks, etc., are 
 operated from the interlocking battery, the current taken for 
 this purpose must be included in figuring the capacity of the 
 battery. The current required by these devices can be secured 
 by reference to tables on pages 265 to 269. The capacity of 
 battery required for this purpose is obtained by multiplying the 
 current taken by said auxiliary devices by the average number 
 of hours such apparatus is energized per day, and by the num- 
 ber of days between charges. 
 
 RESERVE AMPERE HOURS 
 
 Under normal operating conditions the battery should not 
 be fully discharged on account of the fact that charging cur- 
 rent may not be always instantly available when wanted, in 
 which case the time would surely come when the plant would 
 be without means of operation. It is, therefore, necessary to 
 have the battery of such size that at the usual time of charging 
 there will be a certain number of ampere hours capacity left 
 in the battery as a reserve. 
 
 The R. S. A. recommends that under normal conditions the 
 battery never be discharged beyond two-thirds of its total 
 capacity; stated in other words, this means that 50 per 
 cent, must be added to the capacity computed when installing 
 the battery in accordance with R. S. A. specifications. If the 
 
ELECTRIC INTERLOCKING HANDBOOK 157 
 
 battery is to be charged at intervals of a week this will give 
 a reserve of three and one-half days, and if at intervals of 
 two weeks the reserve will be for seven days. When a com- 
 mercial source of power is available, this in all probability 
 will give more reserve than would be necessary. On the 
 other hand, if the charging source is not so reliable, the capacity 
 of the battery may have to be increased. For instance, the 
 charging of the batteries at an isolated plant may be dependent 
 upon a gasoline engine, the failure of which might take several 
 days for repairs due to time spent in securing repair parts, etc. 
 In such a case when the charging is done at intervals of a 
 week, it would, perhaps, be necessary to have a reserve suf- 
 ficient for a full week's operation, this requiring that the 
 computed capacity of the battery be increased by 100 per 
 cent. 
 
 Based on the above, it is recommended as good practice that 
 the battery provide for a minimum reserve of 50 per cent, 
 and that, if local conditions require it, an additional amount 
 of reserve be added as outlined above. 
 
 METHOD OF TABULATION 
 
 When determining the capacity of a battery the different 
 items may be tabulated as shown below; in which 
 
 L stands for 'lever movements per day." 
 
 C stands for 'function constant." 
 
 D stands for 'days operated between charges." 
 
 N stands for 'number of units operated." 
 
 AH stands for 'ampere hours per day per signal." 
 
 A stands for 'amperes." 
 
 H stands for 'hours energized per day." 
 
 Functions LxCxD = ampere hours 
 
 Cut-Outs /io x H x D = ampere hours 
 
 Lighting Signals AH x N x D = ampere hours 
 
 Auxiliary Apparatus ....AxHxNxD= ampere hours 
 
 Total of above = ampere hours 
 
 Reserve to be added = ampere hours 
 
 Total capacity of Battery = ampere hours 
 
 WHEN THE NUMBER OF LEVER MOVEMENTS 
 is NOT KNOWN 
 
 When it is not possible to ascertain the number of lever 
 movements to be made in a given plant, the ampere hour 
 capacity of battery required for the operation of functions 
 and for cut-outs can be secured from the following table; 
 these figures include sufficient reserve to care for ordinary 
 conditions. 
 
158 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TABLE GIVING BATTERY CAPACITY FOR OPERATION 
 FUNCTIONS AND CUT-OUTS 
 
 OF 
 
 Size of Machine 
 
 Size of Battery 
 
 8 to 16 levers 
 16 to 32 levers 
 32 to 48 levers 
 48 to 88 levers 
 88 to 128 levers 
 128 to 168 levers 
 
 40 ampere hour battery 
 60 ampere hour battery 
 80 ampere hour battery 
 120 ampere hour battery 
 160 ampere hour battery 
 200 ampere hour battery 
 
 The table is based on past experience and is considered rea- 
 sonably correct for moderate size machines, the battery sizes, 
 if anything, being somewhat high. The table is not extended 
 for machines larger than 168 levers, as with such plants it is 
 believed that special study of lever movements should be 
 made in the determination of the battery size. 
 
 If the signals are to be lighted and auxiliary apparatus 
 operated from the interlocking battery, an additional number 
 of ampere hours must be added to the figures in the table, 
 the calculation being made in accordance with the preceding 
 paragraphs dealing with the capacity required for electric 
 lighting and for miscellaneous purposes. 
 
 FIG. 107. 
 
 FRONT ELEVATION SECTION A B. 
 
 LEAD TYPE STORAGE BATTERY AND BATTERY CUPBOARD 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
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160 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 G. R. S. BATTERY CHARGING SWITCH 
 
 The battery charging switch illustrated by Fig. 108 provides 
 a simple and efficient means for connecting storage batteries 
 in series with charging and discharge lines, permitting the 
 batteries to be switched off or on to the line without opening 
 the charging circuit. 
 
 During the manipulation of the switch, short circuiting of 
 the battery is avoided by automatically inserting a resistance 
 during the interval that the battery would otherwise be on 
 
 FIG. 108. BATTERY CHARGING SWITCH 
 
 short circuit, which resistance is again cut out as soon as that 
 point is passed. 
 
 Manipulation of the switch is simple, the four different 
 positions of the switch controlling the battery as follows: 
 
 1 Battery A discharging, Battery B charging. 
 
 2 Battery A discharging, Battery B open. 
 
 3 Battery B discharging, Battery A open. 
 
 4 Battery B discharging, Battery A charging. 
 
 The charging switch is compact and substantial in design 
 and so arranged to permit of easy inspection. The commu- 
 tator possesses a high degree of insulation. The contact 
 plates and fingers are large, being designed to take care of the 
 neavy currents necessary in this kind of work without heating. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 161 
 
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DIRECT CURRENT GENERATORS 
 GENERAL DESCRIPTION OF CHARGING APPARATUS 
 
 DIRECT current generators of the shunt wound type are 
 ordinarily used for storage battery charging. The 
 capacities of the generators used in connection with the 
 G. R. S. electric interlocking system run from 1 to 8 K. W., 
 as shown in the table on page 159, the current being delivered 
 at a potential ranging from 110 to 160 volts. 
 
 Where commercial power is available, it is preferable to 
 use a direct connected motor for operating the charging gen- 
 erator. Where such power is not available, a gasoline engine 
 is generally employed to drfVe the generator, either by means 
 of belting or by being directly connected to the generator. 
 
 The charging is generally controlled through the medium of 
 a power switchboard equipped with a no-load, reverse-current 
 circuit breaker, which opens the charging circuit if the gener- 
 ator voltage drops below that of the batteries, thus preventing 
 the generator from running as a motor on current delivered 
 by the batteries. 
 
 A simplified charging circuit is shown by Fig. 110. In this 
 circuit the generator is assumed connected for right-hand 
 rotation; to secure left-hand rotation the field connection 
 should be reversed. 
 
 SETTING UP THE MACHINE 
 
 The generator should be located in a room which is as dry 
 and clean as possible: a room which is hot and dusty should 
 be avoided, particularly if the dirt is of a gritty character, as 
 it is apt to injure the commutator and bearings of the machine. 
 
 The machine should be in plain sight and have sufficient 
 room on all sides for easy access, care being taken that there 
 is sufficient room to permit taking out the armature. 
 
 If the flooring of the power house is firm, the generator or 
 motor generator set may be mounted on a wood block three 
 or four inches thick, screwed to the flooring; if the floor con- 
 struction will not permit this, a concrete foundation should 
 be installed. 
 
 WHEN STARTING GENERATOR FOR THE FIRST TIME 
 
 Before starting the machine for the first time, make sure 
 that the main switch and circuit breaker are open (Fig. 110). 
 Raise the brushes from contact with the commutator and 
 examine them to see if they are in proper condition. Fill 
 the bearings with oil. Make sure that the armature and field 
 coils of the generator have not become wet during shipment 
 or while being stored ; if any sign of dampness is noted they 
 should be dried out, following the instructions on page 165. 
 
 Run the generator light for a time, noting whether the oil 
 rings are working properly, and if the generator is belt driven, 
 
ELECTRIC INTERLOCKING HANDBOOK 163 
 
 note whether the machine is so lined up that the belt runs 
 central on the pulleys and the armature plays freely back and 
 forth between its bearings. At no-load the speed of the gener- 
 tor should be slightly high, so that at full-load it will come 
 down to approximately that indicated on the name plate. 
 
 After making sure that the commutator brushes are still 
 raised, cut the rheostat fully "in" and then close the main 
 switch and the circuit breaker (Fig. 110). Cut the rheostat 
 "out" gradually and then "in" again, after which the main 
 switch should be again opened. This procedure causes cur- 
 rent to flow through the generator fields and insures the 
 field coils having a proper residual magnetism. Replace the 
 brushes on the commutator and shift the brush holder, if 
 necessary, to bring the brushes to the "neutral" position. 
 
 POWER SHITCH BOARD 
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 FIG. 110. SIMPLIFIED CHARGING CIRCUIT 
 
 After the machine is running and has built up, the brushes 
 should be rocked backward and forward until the point 
 of minimum sparking is found. When the machine is run- 
 ning under load this should be again checked and the position 
 of the brushes shifted again if necessary; lock and leave 
 brushes in this position. 
 
 To START THE CHARGE 
 
 See that the main switch and circuit breaker are open, and 
 that the rheostat resistance is all cut "in." 
 
 Get the generator up to speed and make sure that the 
 brushes are in proper position and that the oiling rings are 
 working properly. 
 
 See that the belt has the proper tension ; that is, it should 
 be as loose as possible and yet not slip or tend to run off the 
 pulley with load on. 
 
 Cut the rheostat resistance "out" until the voltage is a 
 little higher than that of the battery, being sure that the 
 voltmeter needle deflects in the same direction for both 
 generator and battery (see switch No. 2, Fig. 118). This 
 
164 GENERAL RAILWAY SIGNAL COMPANY 
 
 latter insures that the positive terminal of the generator will 
 be connected to the positive pole of the battery. 
 
 Close the main switch and circuit breaker and adjust the 
 rheostat until the proper amount of current is flowing into 
 the battery, also adjust the brushes if necessary for minimum 
 sparking. It will be necessary to change the adjustment of 
 the rheostat occasionally as the battery charging increases, in 
 order to maintain the current at the proper amount. 
 
 To SHUT DOWN 
 
 To shut down, lower the voltage by cutting "in " the rheostat 
 until the circuit breaker on the switchboard opens of itself 
 and then stop the engine. If no circuit breaker is provided, 
 wait until the current is practically at zero before opening the 
 main switch on the battery. After the machine has stopped, 
 relieve the tension on the belt so as to prevent it from stretch- 
 ing during such time as the machine is standing idle. 
 
 GENERAL INSTRUCTIONS 
 
 It is hardly possible to give detailed and complete instruc- 
 tions in these pages for locating all the troubles which may 
 arise in the use of such apparatus. The type of machine 
 used for charging storage batteries is so simple, however, that 
 by adhering to the following general instructions, it is believed 
 that satisfactory operation of the machine will be obtained. 
 
 The generator should be kept perfectly clean and dry and 
 should not be unnecessarily exposed to dust. This can best 
 be accomplished by throwing a waterproof covering over the 
 machine when not in use. 
 
 Do not overload the machine. To load the machine beyond 
 the capacity indicated on its name-plate is never conducive 
 to best operation, this being the frequent cause of over- 
 heating in the machine, sparking at the commutator, or other 
 troubles. 
 
 Overheating the generator may be readily detected by 
 applying the hand to the various parts of the machine; in 
 general a temperature that cannot be borne by the hand is to 
 be considered excessive. An odor of burning varnish is indi- 
 cative of serious overheating, and a machine which shows this 
 symptom should have the load removed at once; rotation of 
 the armature may be continued with the fields de-energized 
 for the purpose of cooling the machine. 
 
 The < bearings should be kept thoroughly lubricated with 
 the bqst grade of lubricating oil. While the machine is run- 
 ning, care should be taken from time to time to see that the 
 oiling rings are working correctly. 
 
 Particular attention should be given to the commutator 
 and brushes to see that the former keeps perfectly smooth 
 and that the latter are in perfect adjustment. The commuta- 
 tor should assume a dark brown, glossy appearance, if proper 
 brushes are used and are kept from sparking, and if -the 
 
ELECTRIC INTERLOCKING HANDBOOK 165 
 
 capacity of the machine as indicated on the name plate is not 
 exceeded. The condition of the commutator and brushes may 
 be regarded as the best barometer of the condition of the 
 generator. 
 
 The free use of lubricants on the commutator is not recom- 
 mended. In cleaning the commutator a tightly woven cloth 
 (free from lint) or chamois skin, should be used and the 
 commutator then wiped with a rag which has a little vaseline 
 on it. 
 
 To fit the brushes to the commutator draw No. 00 sand- 
 paper under them, smooth side to the commutator, as shown 
 in Fig. Ill, the brushes to bear on the sandpaper only when 
 
 HANDLE 
 
 COMMUTATOR ' 
 
 Fia. 111. METHOD OF FITTING BRUSHES TO COMMUTATOR 
 
 it is being drawn in the direction in which the surface of the 
 commutator will run when the machine is in operation. After 
 the brush is shaped to the commutator finish up with No. 
 sandpaper and then carefully clean the commutator and 
 brushes of all particles of dust or grit. 
 
 The brushes shipped with the machine are ordinarily best 
 adapted to the work and other brushes are liable to cause 
 trouble. A little oil may be applied to the brushes should 
 they become dry and noisy. 
 
 If the armature or field coils of the generator should become 
 wet, they should be thoroughly dried out before running the 
 machine under load as the moisture is liable to damage the 
 windings. The coils of the machine may be dried out by 
 baking in an oven at a temperature of 240 degrees Fahr. 
 for several hours, or if an oven is not available they may 
 be dried out by placing near the fire. Another method is 
 to run the generator for several hours without exciting its 
 field. 
 
166 GENERAL RAILWAY SIGNAL COMPANY 
 
 GENERATOR FAILS TO BUILD UP 
 
 One of the common troubles which occurs in the operating 
 of generators is the failure of the machine to build up. This 
 failure may be generally attributed to one of the following 
 causes: 
 
 1. Open circuit due to a broken wire, faulty connec- 
 tions, brushes up, fuse blown, open switch, etc. 
 
 2. Reversed connections in field circuit or reversed 
 direction of rotation. 
 
 3. Excessive resistance due to poor brush contact. 
 Brush contacts often have an excessively high resistance 
 when generator is first started, and a momentary pressure 
 of the fingers on the brush or brushes may enable the 
 machine to build up. 
 
 4. Weak, destroyed or reversed residual magnetism. 
 To restore residual magnetism send current from battery 
 through the fields in the proper direction. 
 
 5. Brushes not in their proper position. 
 
 6. Short circuit in the machine or in the external 
 circuit. 
 
 R. S. A. SPECIFICATIONS FOR ELECTRIC 
 
 GENERATOR (1910) 
 1. MATERIAL 
 
 (a) The generator shall be shunt wound, self-excited, shall 
 have self-oiling bearings, carbon brushes, rheostat, and 
 when belt connected, a belt tightener, sub-base, and pulley. 
 
 (b) The normal or rated speed shall not exceed fifteen 
 hundred (1500) r. p. m. except when direct connected to an 
 a. c. motor or steam turbine. 
 
 (c) The generator shall have a continuous current 
 
 capacity equal to the eight (8) hour rate ( 
 
 ampere) of the battery, at a voltage equal to the maximum 
 
 voltage ( volts) of the battery on charge, 
 
 without a rise in temperature in any part exceeding 
 seventy-two (72) degrees Fahr. (40 C.) above the tem- 
 perature of the surrounding atmosphere. 
 
 (d) It shall be so wound that its voltage at the con- 
 tinuous current rating given above, may be varied by 
 means of a field rheostat between the minimum and the 
 maximum charging voltage of the battery. 
 
 (e) The generator shall be capable of supplying for four 
 (4) hours a current output twenty-five (25) per cent, in 
 excess of the continuous current capacity referred to in 
 above without a rise in temperature in any part exceeding 
 ninety (90) degrees Fahr. (50 C.) above the temperature 
 of the surrounding atmosphere. 
 
 (/) It is understood that the temperature of the sur- 
 rounding atmosphere is to be based on seventy-seven (77) 
 
ELECTRIC INTERLOCKING HANDBOOK 167 
 
 degrees Fahr. (26 C.), but should the temperature vary 
 from this, corrections shall be made in accordance with 
 the recommendations of the American Institute of Elec- 
 trical Engineers. 
 
 (gr) The current output of the minimum allowable gen- 
 erator shall be that required for the operation of two (2) 
 switches simultaneously. 
 
 (ft) With the brushes in a fixed position, the generator 
 shall be practically sparkless under all operating condi- 
 tions, as outlined above. 
 
 (i) These generator specifications describe a machine 
 which, in normal power interlocking service, will have an 
 ample overload capacity to meet general requirements. 
 
168 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 
 
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GASOLINE ENGINES 
 GENERAL DESCRIPTION 
 
 GASOLINE engines, used in the charging of moderate 
 sized storage batteries, are generally of the single 
 cylinder four cycle type, water cooled and equipped 
 with the "Make and Break" electric ignition. The vertical 
 type engine is lubricated by the crank dipping into an oil 
 bath in the base of the crank case; oil and grease cups 
 are further provided for lubricating parts not so cared 
 for. 
 
 The operation of the engine is maintained at a constant speed 
 by either regulating the mixture of gasoline vapor or by 
 varying the number of power impulses as soon as a certain 
 
 A- Circulating Tank D - Vent 
 
 B- Return Pipe E- Drain Pipe 
 
 C- Supply Pipe F- Valve 
 
 G- Exhaust Pipe - Engine to exhaust Rot 
 
 FIG. 114. WATER CONNECTIONS FOR 
 
 GASOLINE ENGINE USING 
 
 COOLING TANK 
 
 FIG. 115. WATER CONNECTIONS 
 
 FOR GASOLINE ENGINE 
 
 COOLED BY RUNNING 
 
 WATER 
 
 speed is exceeded ; the engines so controlled are known as the 
 "Throttling Governor" or the "Hit and Miss" types, respect- 
 ively. 
 
 In a common type of engine used for this work, a pump 
 supplies gasoline to a reservoir, an overflow pipe being con- 
 nected with the reservoir to maintain the gasoline at a uniform 
 height. At the proper time in the cycle of operation, the 
 engine piston sucks air through the air inlet passage and at 
 such a velocity that gasoline is picked up from the reservoir 
 and drawn through an adjustable nozzle into the cylinder 
 head, the gasoline mixing with the air to form the required 
 explosive vapor. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 171 
 
 LOCATION OF ENGINE 
 
 In locating the engine, at least two feet should be left on 
 all sides of engine for convenience in starting and for having 
 sufficient room to make necessary adjustments and repairs. 
 
 The gravity system of circulation is generally used for the 
 cooling water. With this system, the tank for the cooling 
 water is generally placed on the floor, as shown in Fig. 114 ; best 
 results are secured, however, by having the tank elevated 
 enough to bring the bottom above the lower water opening on 
 the engine cylinder. Connections should be as shown, large 
 enough piping being used to permit free circulation of the 
 water. Valves F-F must be inserted in the pipe line to permit 
 drawing off the water from engine in freezing weather without 
 emptying the tank. 
 
 The gasoline tank should be located outside of the building, 
 
 FIG. 116. GASOLINE TANK LOCATION 
 
 and with engines equipped with a gasoline pump, the tank 
 should be placed at a lower level than the engine, so that when 
 the engine is idle the gasoline will drain back into the tank. 
 In making the connections between the gasoline tank and 
 engine, care must be taken to wash out all piping and joints 
 with gasoline to remove any loose matter or scale from the 
 interior of such connections. 
 
 To START ENGINE 
 
 See that engine is properly oiled and that water and gasoline 
 valves are turned on. Pump gasoline into reservoir. Fill 
 priming cock on head of cylinder; this may not be necessary 
 in warm weather. Make sure that spark lever is in "retard" 
 or "late" position, then close switch to ignition circuit. 
 
 Turn engine fly-wheel in normal direction of rotation. 
 
 After ignition occurs, remove starting crank, advance spark 
 lever to "early" position and regulate the throttle valve. It 
 
172 GENERAL RAILWAY SIGNAL COMPANY 
 
 will be found that this last adjustment varies with the tem- 
 perature, requiring much coarser adjustment with cold weather 
 than with warm. 
 
 Load should not be thrown on the engine until after it is in 
 operation. 
 
 To STOP ENGINE 
 
 Close throttle valve and open switch on battery. If it is 
 freezing weather, water should be drawn off from engine. 
 
 GASOLINE ENGINE TROUBLES 
 
 IGNITION TROUBLES 
 Engine misses or fails to start 
 
 (a) Weakened Batteries. 
 
 (b) Strong Batteries, but with following defects: 
 
 1. Switch in "OFF" position. 
 
 2. Insulation on wire worn, causing short circuit. 
 
 3. Circuit open by broken or loose connections. 
 
 4. "Make and Break" mechanism inoperative, due 
 
 to broken spring, bearing stuck, etc. 
 
 5. "Make and Break" mechanism contacts fouled. 
 
 6. "Make and Break" adjustments incorrect. 
 
 7. Broken down spark coil. 
 
 CARBURETION DIFFICULTIES 
 Engine misses or fails to start 
 (a) Fuel Supply tank and pipe line : 
 
 1. Throttle valve closed. 
 
 2. Tank empty. 
 
 3. Tank vent stopped up. 
 
 4. Gasoline pump inoperative. 
 
 5. Gasoline pipe plugged. 
 
 6. Water in gasoline. 
 (6) Mixture too rich : 
 
 1. Throttle valve adjustment incorrect. 
 
 2. Air passage clogged. 
 
 (c) Mixture too weak : 
 
 1. Throttle valve adjustment incorrect. 
 
 2. Spray valve partially stopped up. 
 
 3. Intake pipe leaky. 
 
 Loss OF COMPRESSION 
 Engine misses, looses power, or fails to start 
 (a) Improper valve operation: 
 
 1. Valves do not lift at proper time ; due to loosening 
 
 or stripping of gearing on cam or crank shafts. 
 
 2. Valves fail to seat properly or too slow; due to 
 
 weak spring. 
 
ELECTRIC INTERLOCKING HANDBOOK 173 
 
 3. Worn cam followers, cams, push rods, etc. 
 (&) Leaky piston rings. 
 
 (c) Priming valve open or leaky. 
 
 (d) Leak in cylinder head packing. 
 
 (e) Failure of lubricating system (engine hot) : 
 
 1. Oil valve shut off. 
 
 2. No oil in oil cups. 
 
 3. Oil drained out of crank case (vertical engine). 
 (/) Failure of cooling system (engine hot) : 
 
 1. Valve in water piping closed. 
 
 2. No water in cooling tank. 
 
 3. Water below normal level (gravity system of 
 
 circulation). 
 
 4. Water piping plugged. 
 
 5. Pump out of order (forced circulation). 
 
 CANNOT CRANK ENGINE 
 
 (a) Engine heated due to failure of lubricating or cooling 
 
 systems. 
 
 (&) Crank or connecting rod bearing overheated or seized, 
 
 (e) Piston overheated or seized. 
 
 (d) Timing gears broken or jammed. 
 
 (e) Connecting rod disconnected, broken or bent. 
 (/) Crank shaft broken or bent. 
 
 (0) Water in pump frozen (force system of water circu- 
 lation). 
 
 MECHANICAL DIFFICULTIES 
 Engine misses, looses power, or fails to start 
 
 (a) Externally apparent : 
 
 1. Valve spring weakened or broken. 
 
 2. Valve stem bent, broken, or gummed. 
 
 3. Valves leaky (carbon on seats). 
 
 4. Valve stem and cam-follower always in contact 
 
 (no clearance). 
 
 5. Muffler or exhaust pipe obstructed. 
 (?>) Internally apparent : 
 
 1. Cylinders or valves carbonized. 
 
 2. Piston rings gummed or broken. 
 
 3. Leaky piston rings, slots in line. 
 
 4. Cam head worn, shifted or broken. * 
 
 5. Piston head or cylinder wall cracked. 
 
 6. Piston rings and cylinder wall scored. 
 
 Loss OF POWER WITHOUT MISSING 
 
 (a) Ignition system adjustments wrongly set. 
 
 (6) Carbureter adjustments wrongly set. 
 
 (c) Lubricating system operating imperfectly. 
 
 (d) Cooling system operating imperfectly. 
 
 (e) Poor valve operation. 
 
 (/) Batteries weakened, giving poor spark. 
 
174 GENERAL RAILWAY SIGNAL COMPANY 
 
 (gf) Mechanical difficulties, such as worn valve connections, 
 
 etc. 
 
 (h) Intake pipe leaky. 
 (i) Muffler or exhaust obstructed. 
 (/) Engine bearings overheated. 
 
 EDITOR'S NOTE 
 
 Above articles based on data furnished by Fairbanks-Morse & 
 Company. 
 
 R. S. A. SPECIFICATIONS FOR GASOLINE ENGINE 
 WITH FUEL AND WATER TANKS (1910) 
 
 1. ENGINE 
 
 (a) The recommended brake horse power of the gasoline 
 engine shall be not less than one and three-fourths (1%) 
 times the kilowatt capacity of the generator at the maxi- 
 mum voltage and the eight (8) hour charging rate. 
 
 (6) The engine shall run without injurious vibration and 
 shall operate continuously at Manufacturer's specified 
 capacity for a period of sixteen (16) hours without injurious 
 heating in any part. 
 
 (c) Regulation in speed shall be within three (3) per 
 cent, from no load to full load and the regulation as re- 
 corded on the voltmeter for a given current shall not vary 
 more than two (2) per cent, between impulses. 
 
 (d) Electrodes on the engine for electric ignition shall be 
 tipped with platinum or an equally serviceable material. 
 
 (e) Manufacturer's standard exhaust muffler shall be 
 provided. 
 
 (/) Engine and accessories shall be acceptable by and 
 installed under the rules of the National Board of Fire 
 Underwriters and the attached requirements of local 
 authorities. 
 
 (g) Engines of twenty-five (25) horse power or less shall 
 not exceed a speed of four hundred (400) r. p. m. 
 
 2. TANKS 
 
 (a) Gasoline tank of gallons capacity shall 
 
 be furnished. Fuel and cooling tanks shall be made of 
 iron or steel with bra-zed or riveted seams. 
 
 (6) Tanks shall be galvanized after they are put together. 
 
 (c) For tanks either for fuel or water, selection shall be 
 made, when practicable, from the following table: 
 
 Gallons Inches in Inches in Gauge metal 
 
 capacity diameter length Head Body 
 
 66 18 68 14 16 
 
 120 24 66 12 14 
 
 500 36 120 10 12 
 
 As a guide in ordering tanks, it is good practice to con- 
 
ELECTRIC INTERLOCKING HANDBOOK 175 
 
 sider that it will require one-tenth (Ho) of a gallon of gaso- 
 line per horse power hour for gasoline engines. 
 
 (d) For cooling, the minimum of free running water 
 should be not less than ten (10) gallons per horse power 
 hour, and for the circulation tank system not less than 
 fifty (50) gallons per horse power. 
 
 (e) Sufficient piping shall be furnished to locate the 
 gasoline tank feet from the engine. 
 
 (/) Unions in all piping shall be equipped with ground 
 brass seats. 
 
 (g) Unless otherwise specified, an iron or a steel cooling 
 tank of sufficient capacity for a continuous run of ten (10) 
 hours on one (1) filling, with connections and removable 
 cover, shall be furnished. Connections between engine 
 and tank shall be arranged for convenient and complete 
 drainage of the cooling system, for independent drainage 
 of the engine and tank, and to conduct all waste water 
 and steam to the outside of the building. 
 
 (h) When engine is installed in same building with 
 storage batteries outside air intake shall be provided. 
 
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180 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 181 
 
 Motor 
 
 Starter 
 
 .88 88 . 
 
 1 
 
 o 
 
 (0 
 
 -E; 
 
 z'-o* 
 
 i 
 
 FIG. 125 
 
 STARTING PANEL FOB 
 SINGLE PHASE A. C. 
 MOTOR 
 
 Z'Q"- 
 
 Fio. 126 
 
 STARTING PANEL FOR 
 
 THREE PHASE A. C. 
 
 MOTOR 
 
 z o" 
 
 FIG. 127 
 
 STARTING PANEL FOR 
 D. C. MOTOR 
 
 FIG. 128 
 
 FIG. 129 
 STANDARD OPERATING SWITCHBOARD 
 
 Polar Relay Contacts 
 
 To test for ground, throw switch No. 1 to the right or left. If the 
 lamp lights when pressed to the right it shows that the negative wire is 
 grounded. If lamp lights when pressed to the left it shows that the 
 positive wire is grounded. 
 
 Red lamps lighted shows that the circuit breaker is open. 
 
182 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 12" 
 
 1 
 
 * 
 
 FIG. 130 
 
 LIGHTING PANEL WITH FIVE 
 
 SINGLE POLE, SINGLE 
 
 THROW SWITCHES 
 
 FIG. 131 
 
 LIGHTING PANEL WITH THREE 
 
 DOUBLE POLE, SINGLE 
 
 THROW SWITCHES 
 
 1 
 
 C^J 
 
 j 
 
 FIG. 132 
 
 LIGHTING PANEL WITH TEN 
 
 SINGLE POLE, SINGLE 
 
 THROW SWITCHES 
 
 FIG. 133 
 
 LIGHTING PANEL WITH FIVE SINGLE 
 
 POLE, SINGLE THROW SWITCHES 
 
 AND ONE DOUBLE POLE, 
 
 DOUBLE THROW 
 
 SWITCH 
 
 1 
 
 H tz" 
 
 FIG. 134 
 
 LIGHTING PANEL WITH Two 
 
 DOUBLE POLE, DOUBLE 
 
 THROW SWITCHES 
 
 J 
 
 FIG. 135 
 
 LIGHTING PANEL WITH FOUR 
 
 SINGLE POLE, DOUBLE 
 
 THROW SWITCHES 
 
SECTION VII 
 
 INSTALLATION AND OPERATING DATA FOR 
 ELECTRIC INTERLOCKING MACHINES 
 
 COVERING INSTRUCTIONS FOR INSTAL- 
 LATION AND MAINTENANCE; ALSO 
 DATA FOR THE APPLICATION AND 
 OPERATION OF LEVER LOCKS 
 
INSTRUCTIONS COVERING THE INSTALLA- 
 TION AND MAINTENANCE OF THE 
 MODEL 2 ELECTRIC INTER- 
 LOCKING MACHINE 
 SHIPMENT 
 
 BEFORE shipment the interlocking machine is assembled 
 complete in every detail and subjected to a rigid electric 
 and mechanical test. It is then partly disassembled, 
 the levers, lever tappets and locking, the legs and lower tiers 
 of locking plates (if furnished) being boxed separately from 
 the body or the machine. This latter is then divided into 
 sections of approximately forty lever spaces and boxed 
 on skids for shipment. Before boxing, all machined parts 
 are wiped dry and coated with vaseline to guard against the 
 effects of rust during . transit. 
 
 STORING 
 
 Upon the receipt of the machine it should be stored in a 
 dry place. If some time passes before the machine is set up 
 and there is any chance of its different parts rusting, these 
 parts should be wiped dry and recoated with vaseline. 
 
 INSTALLATION 
 
 The first step in the assembly of the machine is to bolt the 
 sections to their supporting legs and the various sections to 
 each other. The legs are numbered and the machine beds 
 marked to correspond. Extreme care should be taken in 
 shimming up under the legs to insure accurate alignment of 
 the bed and an even distribution of the weight on the sup- 
 porting legs. Failure to do this, especially in a large machine, 
 is very likely to result in binding between the various parts of 
 the mechanical locking. 
 
 The second and third tiers of locking plates, if used, should 
 be assembled on the machine, care being taken to place the 
 templet furnished for the purpose in the horizontal and vertical 
 locking slots before doweling the locking plates to their sup- 
 port. Never file the screw holes when mounting these plates 
 since this is not necessary if the bed has its correct alignment. 
 To permit of the plates being placed in the same location as 
 when the machine was assembled in the factory, the second 
 tier of plates are numbered 1, 2, 3, etc., from left to right, and 
 the third tier 1A, 2A, 3A, etc., also from left to right. 
 
 The locking should then be assembled in the locking plates 
 and the lever tappets placed in their proper positions. Each 
 locking dog is stamped with the number of the tappet with 
 which the dog is to engage and the locking bars with numbers 
 to correspond with the slot in which they are to be placed, 
 these slots being numbered in sequence from the top of the 
 
186 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 CABINET 
 
 FIG. 136. MODEL, 2 UNIT LEVER TYPE INTERLOCKING MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 187 
 
 FIG. 137. MODEL 2 INTERLOCKING MACHINE 
 
188 GENERAL RAILWAY SIGNAL COMPANY 
 
 locking bed to the bottom (thirty-two slots per tier of locking). 
 Each tappet is stamped with the number of the lever to which 
 it is to be attached. 
 
 The levers should then be placed in their respective guides, 
 and worked back and forth to insure that they operate freely, 
 that they are checked at the normal and reverse indication 
 points, and that they can be moved to the full normal and 
 full reverse when indicated. (Signal levers are not indicated 
 on the reverse movement.) The circuit controllers and 
 tappets should be carefully fastened to their respective levers, 
 and the levers tried for freedom of movement with all working 
 parts connected. 
 
 The buss bars, buss wires and the connections between the 
 individual polarized relays, which have been separated during 
 shipment, should be securely connected by joining the short 
 leads provided on the machine for the purpose. 
 
 TESTING 
 
 A careful test should be given to the mechanical locking 
 by setting up the various routes in accordance with the track 
 plan or manipulation chart, testing the various levers in the 
 route to see that they are locked and likewise testing all levers 
 which conflict with the given route. This will insure that 
 none of the locking parts have been omitted in assembling. 
 
 When wiring up the interlocking machine it is well to check 
 up the controller contacts to see that all special contacts 
 called for by the wiring plans have been provided. 
 
 The lever and its connections will be checked up as the 
 individual functions are tested out; i. e., the completed opera- 
 tion of the function normal and reverse, shows that the lever 
 wiring is correct, its controller springs making good contact, 
 that the indication magnet operates properly, and if the func- 
 tion is a switch, that the indication selector also is giving 
 proper operation. If desired, a check can be secured on the 
 polarized relays by making the cross protection tests described 
 on page 94. 
 
 MAINTENANCE 
 
 The maintenance of the interlocking machine principally 
 consists in keeping the machine cleaned, all connections tight, 
 and of wiping with an oiled rag at stated intervals such parts 
 as are liable to rust. 
 
 When cleaning or oiling the locking, it should not be re- 
 moved from the interlocking machine. Use only high-grade 
 oils, such as "3 in One," "Hydrol" or "Polar Ice." 
 
 Commercial fuse wire should not be used to replace the fuses 
 furnished with the machine, since commercial wire is not 
 carefully graded and may carry a much larger current without 
 melting than the fuses secured from the manufacturer. 
 
 As a general statement, it may be said that the operation of 
 the various functions is a good check on the condition of the 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 189 
 
 interlocking machine, since the completed operation of the 
 various functions gives assurance as to the integrity of all parts 
 of their operating circuits. It is well, nevertheless, to antici- 
 pate the possibility of loose connections, etc., and at stated 
 intervals to make inspections of the different connections, 
 
 FIG. 138. MODEL, 2 UNIT LEVER TYPE INTERLOCKING MACHINE. 
 
 EQUIPPED WITH SPRING COMBINATION BOARD 
 Note location of polarized relays, buss bars and fuses. 
 
 contacts and various mechanical parts on the interlocking 
 machine to insure that all parts are kept in the best condition. 
 As mentioned above, the operator may assure himself as to 
 the constant integrity of the cross protection by means of the 
 simple tests described on page 94. 
 
190 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
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ELECTRIC INTERLOCKING HANDBOOK 
 
 191 
 
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INSTRUCTIONS FOR CUTTING AND TESTING 
 
 NOTCHES FOR LEVERS CONTROLLED 
 
 BY LEVER LOCKS 
 
 WHERE lever locks are applied to machines before ship- 
 ment from the factory, the notches are cut in the 
 levers as nearly right as possible, it being understood 
 that before the machines are put into service on the ground 
 the clearance will again be checked up by test and the 
 notches cut out further, if necessary, to give the proper clear- 
 ance. This clearance should be at least equal to that indi- 
 cated below when the lever in question is locked by other 
 levers through the medium of the tappet locking, and also 
 when said lever is pulled or pushed hard in either direction 
 to take up all lost motion, the lever latch being lifted at the 
 time. 
 
 The lever should be tested as above for clearance for every 
 combination that locks it. 
 
 In making the test for clearance, proceed as follows: 
 
 With the lever full normal (Fig. 139), set up some one com- 
 bination that locks it; lift lever lock (A) by applying current, 
 also the lever latch (B), and pull the lever strongly toward the 
 reverse position, as indicated by the arrow, thus taking up all 
 lost motion, and then with a scriber mark this position of the 
 lever. Then drop the lever lock by cutting off the current, 
 release mechanical locking that is holding the lever, and again 
 pull the lever toward the reverse position until it takes up 
 against the lever lock, and again mark the position of the lever 
 with a scriber. The distance between these scriber marks 
 will then tell the clearance "D " existing. Repeat this process 
 for every combination that locks the lever in its normal posi- 
 tion, and if the clearance "D" thus found is less than one- 
 eighth inch, the notch in the lever is to be cut out further to 
 give the proper clearance. 
 
 Then with the lever full reverse (Fig. 140), set up some one 
 combination that locks it ; lift lever lock (A) by applying cur- 
 rent to it, also the lever latch (B), and push the lever strongly 
 toward the normal position as indicated by the arrow, thus 
 taking up all lost motion, and then with a scriber mark this 
 position of the lever. Then drop the lever lock by cutting off 
 the current, release the mechanical locking that is holding the 
 lever, and again push the lever toward the normal position until 
 it takes up against the lever lock, and again mart the position 
 of the lever with a scriber. The distance between the two 
 scriber marks will then tell the clearance "D " existing for the 
 reverse position of the lever. Repeat this process for every 
 combination that locks the lever in its reverse position, and 
 if the minimum clearance "D" thus found is less than three- 
 sixteenths inch, the notch in the lever is to be cut out further 
 to give the proper clearance. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 193 
 
 Tests must also be made to determine that the clearance (C) 
 is sufficient to permit the lock to drop into its notch when the 
 lever is pushed as far normal as it is possible to get it, or is 
 pulled as far reverse as it is possible to pull it. This clearance 
 "C" can be checked by causing the lock plunger to be raised 
 
 LEVER LATCH B 
 
 FIXED STOP FOR LEVER LATCH *& 
 
 LOCK PLUNDER "A" 
 
 IXEO GUIDE FOR LOCK PLUNGER V 
 REVERSE NOTCH 
 
 -TAPPET BAR 
 
 FIG. 139. NOTCHING OF LEVER FOB LEVER LOCK. NORMAL POSITION 
 
 FIXED OUIOE FOR LOCK PLUN6ER "A* 
 LOCK PLUNGER A* 
 
 FIXED GUIDE FOR TAPPET BAR 
 TAPPET BAR 
 
 FIG. 140. NOTCHING OF LEVER FOR LEVER LOCK. REVERSE POSITION 
 
 and lowered, by making and breaking the circuit thus applying 
 energy to the lock, and if the plunger drops into the notch it 
 is known that the clearance is there. 
 
 In cutting the notches see that the corners are left square 
 and the surface that comes against the lock plunger is vertical, 
 so that there may be no tendency to force the lock plunger out 
 by pulling hard on the lever. 
 
194 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Test each lock by putting on and taking off current several 
 times to see that it works properly. If proper, its operation 
 will be quick and sharp. 
 
 Interlocking levers should be tested periodically when in 
 service, in accordance with above instructions, to see that 
 sufficient clearance exists between the lock plunger and the 
 notch in the lever. 
 
 It will be sufficient if above inspection is made once a year. 
 
 When lever locks are applied to interlocking machines after 
 they have been installed it is sometimes necessary to get 
 additional clearance between the lock plunger and the lever 
 guides. This is to prevent the plunger from sticking to the 
 lever guides when the lock is energized. 
 
 The lever guide should be marked and chipped where 
 necessary, so that no part of the lever guide will be closer to 
 the plunger than one-eighth inch. 
 
 The chipping should be done with a light hammer and a 
 small cape chisel, and every precaution should be taken to 
 prevent the chips of iron from getting into the indication mag- 
 net coils. 
 
 ENERGY DATA FOR INDICATION MAGNETS FOR MODEL 2 
 INTERLOCKING MACHINE 
 
 
 
 FOR SATISFACTORY OPERATION 
 
 Indication 
 Magnet for 
 
 Ohms 
 Resis. 
 
 Should Indicate on 
 
 Should not Indicate on 
 
 
 
 Volts 
 
 Amps. 
 
 Volts 
 
 Amps. 
 
 Solenoid Dwarf, . . 
 
 800 
 
 90 
 
 .112 
 
 50 
 
 .0625 
 
 Model 3 Signal, . . 
 
 1.42 
 
 1.85 
 
 1.30 
 
 1.28 
 
 .90 
 
 Model 2A Signal, . 
 
 6.80 
 
 3.06 
 
 .45 
 
 2.58 
 
 .38 
 
 L. V. Battery, . . . 
 
 13.60 
 
 4.35 
 
 .32 
 
 3.40 
 
 .25 
 
 Switch Machine, . . 
 
 1.42 
 
 1.85 
 
 1.30 
 
 1.28 
 
 .90 
 
 A. C. 25 Cycles, . . 
 
 7.00 
 
 35 
 
 
 
 
 A. C. 60 Cycles, . . 
 
 7.00 
 
 85 
 
 
 
 
 NOTE. Values given above are for magnets mounted on interlocking 
 machine. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 195 
 
 FIG. 141. LEVER LOCK FOR MODEL 2 INTERLOCKING MACHINE 
 
 ENERGY DATA FOR LEVER LOCKS OPERATING ON 
 DIRECT CURRENT 
 
 Resistance 
 Ohms 
 
 Mil Amps. 
 
 Volts 
 
 14.5 
 
 360 
 
 5.2 
 
 35 
 
 238 
 
 8 
 
 75 
 
 173 
 
 13 
 
 120 
 
 133 
 
 16 
 
 250 
 
 120 
 
 30 
 
 1400 
 
 46 
 
 64 
 
 1500 
 
 53 
 
 80 
 
 NOTE. Values given in above table are the minimum on which the lock 
 will operate. Add 10 per cent, for practical operation. Drop away cur- 
 rent equals 23 per cent, of the minimum operating current. 
 
 ENERGY DATA FOR LEVER LOCKS OPERATING ON 
 ALTERNATING CURRENT 
 
 Resistance 
 Ohms 
 
 Frequency 
 
 Volts 
 
 35 
 
 25 cycles 
 
 25 
 
 8.6 
 
 60 cycles 
 
 25 
 
 NOTE. Values given in above table are the minimum on which the lock 
 will operate. Add 10 per cent, for practical operation. Drop away voltage 
 equals 50 per cent, of the minimum operating voltage. 
 
SECTION VIII 
 
 INSTALLATION AND OPERATING DATA FOR 
 SWITCH MECHANISMS 
 
 COVERING INSTRUCTIONS FOR IN- 
 STALLATION AND MAINTENANCE, 
 ENERGY FIGURES, CLEARANCES 
 REQUIRED, DIMENSIONS, TIE 
 FRAMINGS, STANDARD LAYOUTS, 
 AND TYPICAL CIRCUITS; ALSO 
 DATA ON DETECTOR BAR FIT- 
 TINGS, SWITCH CIRCUIT CONTROL- 
 LERS AND BRIDGE CIRCUIT 
 CLOSERS 
 
INSTRUCTIONS COVERING THE INSTALLA- 
 TION AND MAINTENANCE OF THE 
 MODEL 2 SWITCH MACHINE 
 
 A' 
 
 STORING MECHANISMS 
 
 LL mechanisms and motors should be placed right side 
 up on timbers to raise them above the ground. The pole 
 changers should be housed in a dry place. 
 
 INSTALLATION 
 
 In making the installation, the first operation is the framing 
 of the ties. This should be in ^accordance with the plan 
 shown by Fig. 142. All slots cut into the ties should be care- 
 fully cleaned of dirt, chips, etc., before the tie plate is put 
 down and the gearing assembled. ^ 
 
 Unless special features are required, all holes in the tie plate 
 are drilled before leaving the factory, with the exception of 
 those for the toe and slide plates. These should be so located 
 
 FIG. 142 TIE FRAMING FOR MODEL 2 SWITCH MACHINE 
 
200 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 M N 
 
 DETECTOR BAR 
 CONNECTION 
 
 FIQ. 143. MODEL 2 SWITCH MACHINE 
 
 Motor 
 
 Pole Changer 
 Friction Clutch 
 Main Gear 
 Intermediate Gear 
 Cam Crank 
 Stud on Main Gear 
 Driving Rod 
 
 H Lock Crank 
 
 / Lock Plunger 
 
 J Throw Rod 
 
 K Lock Rod 
 
 L Pole Changer Movement 
 
 M Pole Changer Connecting Rod 
 
 N Detector Bar Driving Link 
 
 O Pin 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 201 
 
 that, when the slide plates, toe plates, and rail braces are in 
 place, the proper track gauge will be rigidly maintained. 
 
 The various parts of the switch machine, with the exception 
 of the locking plunger, should then be assembled. In placing 
 the motor, care should be taken to secure proper alignment of 
 the connection between the motor and main gear. 
 
 The throw and lock rods may be connected at this time and 
 the lock plunger holes in the throw rod drilled. The lock rod, 
 however, should not be drilled until it is certain that the track 
 has its final alignment and the rail braces have been fitted, 
 thus insuring that there will be no change in the relative 
 position of the switch points and switch mechanism. Special 
 care should be taken when marking the lock rod to see that the 
 switch points are brought tightly up against the stock rail. 
 The most accurate method of marking the rods is to withdraw 
 the lock plunger and to insert in its place a piece of steel 
 
 FIG. 144 FIG. 145 
 
 Fields in Series. Fields in Multiple. 
 
 WIRING FOR MOTORS, MODEL 2 SWITCH MACHINE 
 
 tubing having an outside diameter of one inch, this tube 
 being pointed so as to make a clear cut mark on the surface of 
 the rod. After putting the machine in service, the top of the 
 lock rod should be notched slightly, as shown by P t , P 2 , P 3 and 
 P 4 in Fig. 146, to permit of a quick inspection being made as 
 to its accurate adjustment. 
 
 In wiring the machine, suitable conduit should be installed 
 to protect the wires running between the trunking and motor, 
 and the motor and pole changer. 
 
 ADJUSTMENTS 
 
 Before making any adjustments with the machine wired up, 
 the brushes should be raised from the motor armature. 
 
 It is necessary that the detector bar be disconnected while 
 making adjustments 1 and 2. 
 
 1. Plunger Connection. 
 
 With the machine placed in either extreme position (that 
 is with stud F at either end of the stroke in cam crank E), 
 
202 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 the driving rod G should be adjusted to such a length that the 
 end of lock plunger I will be flush with the outside face of the 
 lock frame (see Fig. 146). This adjustment never varies, and 
 it should not be changed after once being made correctly. If 
 incorrectly made it is liable to cause indication failure. 
 
 2. Pole Changer Movement. 
 
 When locating pins in the lock rod K for the operation of the 
 pole changer movement, move the switch machine to the 
 extreme position as shown in Fig. 143. Locate pin Q t so that 
 link R will just clear cap S t by five-sixteenth inch (Fig. 146). 
 
 FIG. 146. POLE CHANGER MOVEMENT L FOR MODEL 2 SWITCH 
 
 MACHINE 
 
 Lock plunger I is shown at end of its travel and not in position corre- 
 sponding with that of link R. 
 
 Then throw the switch to the other extreme position and 
 locate pin Q 2 in a similar manner. When assembling the 
 pins on the lock rod, drill, tap, and countersink the lock rod as 
 shown in Fig. 148. 
 
 3. Pole Changer Connection. 
 
 Any lost motion between the pole changer movement L and 
 the pole changer B must be equal at the full normal and full 
 reverse position of the switch machine. To secure this, adjust 
 the connecting rod M with the switch machine in either of its 
 extreme positions. Test with the machine first in the full 
 normal position and then in the full reverse position, pushing 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 203 
 
 and pulling the rod M strongly to determine the total distance 
 it is possible to be moved. Repeat the adjustment until the 
 desired result is obtained. This adjustment never varies in 
 service and it should not be changed after once being made 
 correctly. If it is not made correctly it is very liable to pre- 
 vent the indication being given on the movement of the switch 
 to the position where the greatest lost motion exists. 
 
 4. Pole Changer Commutator. 
 
 The commutator T (Fig. 147) must revolve freely in its 
 bearings, care being taken that the contact springs U lf U 2 
 and U 3 do not have so much tension as to prevent spring V 
 from snapping the commutator over. Adjust so that with 
 machine full normal or reverse, roller W and pin X are in the 
 
 =] 
 
 u 
 
 V-7 
 
 ii s =S<- 
 
 \\ & 
 
 } CONTROL WIRES 
 
 MAIN COMMON 
 FIG. 147. POLE CHANGER WIRING, MODEL 2 SWITCH MACHINE 
 
 relative positions shown. The adjustment of the commutator 
 must be such that the snapping action will take place at such a 
 time that the amount of movement in the contact blocks Z, 
 and Z 2 , which precedes the snapping action, will be equal for 
 the normal or reverse movement. To be certain that this 
 result is obtained it will be necessary to move the mechanism 
 a number of times by hand very slowly. Failure to have the 
 adjustment right will be almost certain to result in damage to 
 the insulating cylinder, due to arcing between the contact 
 spring and the contact cylinder, and may prevent indication. 
 
 The contact springs Ux and U 3 are provided with slots which 
 will permit the springs, when resting on the insulated portion 
 of the commutator, to be centrally located. 
 
 After the commutator adjustments have been completed and 
 machine worked sufficiently to insure correct action, remove 
 
204 GENERAL RAILWAY SIGNAL COMPANY 
 
 one of the set screws from the collar Y, drill into the shaft 
 and replace the screw, running it down until it locks the com- 
 mutator to its shaft; repeat this operation with the other 
 screw located in the collar. 
 
 In connecting up the operating coils to the contact springs 
 Ui and U 3 , be sure to see that when the commutator is in its 
 full normal or full reverse position, the contact spring which 
 rests on the metal cylinder does not carry current. This can 
 be done by lifting it slightly; if a spark results it shows that 
 the contact springs should be interchanged. 
 
 5. Throw Rod. 
 
 The nuts on the throw rod must be placed so that the switch 
 points will be brought up against the stock rail snugly, but 
 not screwed up far enough to put any unnecessary strain on the 
 rod. Under normal conditions, with the throw rod adjusted 
 as above, a single switch or derail should permit of hand 
 operation (without the aid of a wrench or tommy bar) by 
 turning the intermediate gear D a . If it is not possible to do 
 this, steps should be taken to get the switch into this condition. 
 
 6. Lock Rod. 
 
 The drilling of the lock rod should be such that the lock 
 plunger will enter either hole with the switch full normal or 
 full reverse, but will be prevented from entering if a piece of 
 metal one-eighth of an inch thick is placed between the switch 
 point and the stock rail. 
 
 7. Detector Bar. 
 
 To adjust the detector bar, place it in the desired position 
 relative to the top of the rail and adjust the connection N to 
 such a length that with the switch machine in either extreme 
 position, pin O may be inserted without changing the position 
 of either the detector bar or switch machine. 
 
 8. Clutch. 
 
 The nut on friction clutch C, by which the compression of 
 the spring is increased or diminished, should be locked in a 
 position which will enable the motor to operate the switch 
 under normal conditions, but will permit the clutch to slip if 
 there is an obstruction in the switch points. This is deter- 
 mined by starting with the nut unscrewed and gradually 
 tightening it up until the motor operates the switch without 
 any slipping of the clutches. 
 
 Before any adjustments are made on the friction clutch, 
 separate the cones from the pinion and oil the clutch cones. 
 
 TESTING 
 
 The preferred method of testing the operation of the switch 
 mechanism is to operate it by hand, making sure that the motor 
 brushes are raised before attempting to move the machine. 
 This method should be employed as a regular practice. 
 
 If it should become necessary to operate the switch by 
 power, the tests on the switch machine should be carried on 
 under the protection of the operating lever, whenever the 
 
ELECTRIC INTERLOCKING HANDBOOK 205 
 
 conditions are such that the leverman can readily receive and 
 act on signals given him by the man on the ground. 
 
 On the rare occasions when it is not practical to conduct 
 the test under the control of its lever, power may be applied 
 locally by taking both control wires off from their respective 
 binding posts (for contact springs U 4 and U, Fig. 147) in the 
 pole changer, and having first connected spring U 2 with a 
 short piece of wire to the open control contact spring (spring 
 U 4 , Fig. 147), current may be sent through the motor by plac- 
 ing the energized control wire in connection with the other 
 control contact spring (spring U s , Fig. 147) ; with these con- 
 nections the mechanism will be brought to rest upon the com- 
 pletion of its movement without shock. Reverse these con- 
 nections to secure operation in the opposite direction. 
 
 After the machine is completely adjusted, safety requires 
 that it should be operated from the interlocking station sev- 
 eral times, making sure that with the lever in its normal posi- 
 
 FIG. 148. DRILLING FOR PINS Q AND Q 8 IN LOCK ROD K 
 
 tion the switch points will correspond with their position as 
 shown on the track plan. 
 
 MAINTENANCE 
 
 1. Mechanism. 
 
 When inspecting the switch machine always note the posi- 
 tion of the lock plunger relative to the face of lock frame. If 
 it is not flush with the outside face of the lock frame, make 
 sure that stud F is in the corner of cam crank E. With the 
 switch adjusted correctly and the stud F at the end of its 
 travel, there are two conditions which would be responsible 
 for the plunger not reaching its proper position. 
 
 First The rails may have shifted and altered the throw 
 of the switch points, which will put an unusual strain on the 
 switch machine and prevent the full movement of the lock 
 plunger. This will be determined by operating the switch by 
 hand. 
 
 Second The detector bar may have been thrown out of 
 adjustment by the shifting of the rails, this preventing the 
 generation of the indication current. Necessity for readjust- 
 ment is determined by disconnecting the bar, placing it 
 in proper position and the switch machine in either extreme 
 position; if it is not possible to replace the pin O without 
 
206 GENERAL RAILWAY SIGNAL COMPANY 
 
 moving either the machine or detector bar, the connections 
 should be readjusted. 
 
 On each inspection examine the friction clutch to see that it 
 slips properly on overload. 
 
 2. Motor. 
 
 The motor commutator or brushes should not be disturbed 
 unless found necessary. If the commutator becomes dirty, it 
 should be cleaned with chamois skin moistened with oil, any 
 surplus oil being wiped off the commutator by a dry piece of 
 chamois. 
 
 If it becomes necessary to put a new brush into a motor, 
 the brush after being put in position should be seated to the 
 commutator by drawing thin, fine sandpaper under the brush, 
 at the same time pressing the brush against the commutator; 
 the smooth side of the sandpaper should be against the com- 
 mutator. Use for this purpose "00 Single Finishing Flint 
 Sandpaper." 
 
 3. Small Parts. 
 
 All cotter pins, lock washers, binding posts, small nuts and 
 screws, should be inspected at stated intervals to see that they 
 are not working loose. 
 
 4. Contact Surfaces. 
 
 The pole changer contacts should be kept clean and bright. 
 
 5. Oil 
 
 Moving parts not exposed to the weather should be well 
 oiled once a month. All parts, the bearing surfaces of which 
 can be reached by rain, should be oiled immediately after each 
 storm. The friction clutches should be oiled on each inspec- 
 tion trip. 
 
INSTRUCTIONS COVERING THE INSTALLA- 
 TION AND MAINTENANCE OF THE 
 MODEL 4 SWITCH MACHINE 
 STORING MECHANISMS 
 
 An,L mechanisms and motors should be placed right side up 
 on timbers to raise them above the ground. 
 
 INSTALLATION 
 
 In making the installation, the first operation is the framing 
 of the ties. This should be in accordance with the plan 
 shown by Fig. 149. 
 
 Unless special features are required, all holes in the tie plate 
 
 Tie H9 2 
 
 =* 
 
 -4- 
 
 11 
 
 Tie 
 
 
 1 =m y 
 
 Tie H?2 
 
 ~g 
 
 
 
 ^ 
 
 l . t 
 
 -if 
 
 
 ""igr '-!" 
 
 Tie H9 j 
 
 Is 
 
 
 II 1 - 0" > 
 
 
 Fia. 149. TIE FKAMINO FOB MODEL 4 SWITCH MACHINE 
 Ties to be cut as shown in dotted lines for electrified roads using third rail. 
 
208 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Motor 
 Intermediate Gear 
 
 Friction Clutch 
 
 Main or Cam Gear 
 
 Roller on Main Ge 
 
 Locking Bar 
 
 i-G, Rollers on Lockinj 
 
 \-H 9 Locking Dogs 
 Lock Rod 
 
 Throw Rod 
 
 H 
 d 
 
 5 
 
 Locking Bolt 
 
 f Pole Changer 
 Tripper Arm 
 
 Switch Circuit Con 
 Location 
 
ELECTRIC INTERLOCKING HANDBOOK 209 
 
 are drilled before leaving the factory, with the exception of 
 those for the toe and slide plates. These should be so located 
 that when the slide plates, toe plates, and rail braces are in 
 place, the proper track gauge will be rigidly maintained. 
 
 The switch machine should then be bolted down to the tie 
 plate and the throw and lock rods connected. 
 
 ADJUSTMENTS 
 
 As the switch machine is completely assembled in the factory 
 and all parts adjusted to meet the conditions under which the 
 mechanism is to operate, there is very little in the way of 
 adjustments necessary to be made. 
 
 After the machine is wired up, before making any adjust- 
 ments which may be required, the brushes should be raised 
 from the motor armature. 
 
 1. Throw Rod. 
 
 The nuts on the throw rod must be placed so that the switch 
 points will be brought up against the stock rail snugly, but 
 not screwed up far enough to put any unnecessary strain on 
 
 FIG. 151 FIG. 152 
 
 Fields in Series. Fields in Multiple. 
 
 WIRING FOB MOTORS, MODEL 4 SWITCH MACHINE 
 
 the rod. Under normal conditions, with the throw rod adjusted 
 as above, a single switch or derail should permit of hand 
 operation, by using the crank provided for the purpose. If it 
 is not possible to do this, steps should be taken to get the 
 switch into this condition. 
 
 2. Lock Rod. 
 
 The adjustment of the lock rod should be such that the 
 locking dog Hj or H 3 will enter its proper notch in the lock 
 rod I with the switch full normal or full reverse", as the case 
 may be, but will be prevented from entering if a piece of metal 
 one-eighth of an inch thick is placed between the switch 
 point and the stock rail. 
 
 3. Detector Bar. 
 
 To adjust the detector bar, place it in the desired position 
 relative to the top of the rail and adjust the connections to 
 such a length that with the switch machine in its extreme 
 position, pin P may be inserted without changing the position 
 of either the detector bar or switch machine. Check this 
 adjustment with the bar and switch machine in the opposite 
 position and readjust if necessary. 
 
210 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 4. Clutch. 
 
 The nut on friction clutch C, by means of which the com- 
 pression of the spring is increased or diminished should be 
 locked in a position which will enable the motor to operate 
 the switch under normal conditions, but will permit the 
 clutch to slip if there is an obstruction in the switch points. 
 This is determined by starting with the nut unscrewed and 
 gradually tightening it up, until the motor operates the switch 
 without any slipping of the clutches. 
 
 L . nirUjlIL ~.l} CONTROL Huwa 
 
 4. MAIN COMMON 
 
 MAIN COMMON, 
 FIG. 153. POLE CHANGER WIRING, MODEL, 4 SWITCH MACHINE 
 
 TESTING 
 
 The preferred method of testing the operation of the switch 
 mechanism is to operate it by hand by means of the crank 
 provided for this purpose, first making sure that the motor 
 brushes are raised before attempting to move the machine. 
 This method should be employed as a regular practice. 
 
 If it should become necessary to operate the switch by 
 power, the tests on the switch machine should be carried on 
 under the protection of the operating lever, whenever the con- 
 ditions are such that the leverman can receive and act on 
 signals given him by the man on the ground. 
 
 On the rare occasions when it is not practical to conduct 
 the test under the control of its lever, power may be applied 
 locally by taking both control wires off from their respective 
 binding posts (for contact springs Q t and Q 2 , Fig. 153) in the 
 pole changer, and having first connected common post R 
 with a short piece of wire to the open control contact spring 
 
ELECTRIC INTERLOCKING HANDBOOK 211 
 
 (spring Qi, Fig. 153), current may be sent through the motor 
 by placing the energized control wire in connection with the 
 other control contact spring (spring Q a , Fig. 153) ; with these 
 connections the mechanism will be brought to rest without 
 shock upon the completion of its movement. Reverse these 
 connections to secure operation in the opposite direction. 
 
 After the machine is completely adjusted, safety requires 
 that it should be operated from the interlocking station several 
 times, making sure that with the lever in its normal position, 
 the switch points will correspond with their position as shown 
 on the track plan. 
 
 MAINTENANCE 
 
 1. Mechanism. 
 
 Shifting of the rails may prevent correct operation of the 
 switch machine in the following manner : 
 
 First By altering the throw of the switch points, an 
 unusual strain will be put on the switch machine which will 
 prevent the mechanism from locking up. This will be deter- 
 mined by operating the switch by hand. 
 
 Second The detector bar may have been thrown out of 
 adjustment, this preventing the generation of the indication 
 current. Necessity of readjustment is determined by dis- 
 connecting the bar, placing it in proper position and the 
 switch machine in its corresponding extreme position; if it is 
 not possible to replace the pin P without moving either the 
 machine or detector bar, the connections should j? readjusted. 
 
 2. Motor. 
 
 The motor commutator or brushes should not be disturbed 
 unless found necessary. If the commutator becomes dirty, 
 it should be cleaned with chamois skin moistened with oil, 
 any surplus oil being wiped off the commutator by a dry piece 
 of chamois. 
 
 If it becomes necessary to put a new brush into a motor, 
 the brush after being put in position should be seated to the 
 commutator by drawing thin, fine sandpaper under the brush, 
 at the same time pressing the brush against the commutator; 
 the smooth side or the sandpaper should be against the com- 
 mutator. Use for this purpose "00 Single Finishing Flint 
 Sandpaper." 
 
 3. Small Parts. 
 
 All cotter pins, lock washers, binding posts, small nuts and 
 screws, should be inspected at stated intervals to see that they 
 are not working loose. 
 
 4. Contact Surfaces. 
 
 The switch circuit controller and pole changer contacts 
 should be kept clean and bright. 
 
 5. Oil 
 
 Moving parts not exposed to the weather should be well 
 oiled once a month. All parts, the bearing surfaces of which 
 can be reached by rain, should be oiled immediately after each 
 storm. 
 
212 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 r 
 
 it 
 
 i 
 
 _ 
 
 -i 
 
 _i 
 
 j 
 
 =!< 
 
 E 
 
 ill 
 
 
 S 5 5 
 
 "3 ^3* o 
 P^ . .-^ 
 
 O 
 
 _: S 
 
 I II g. 1 1 
 
 P4 O fc; o O 
 
 = tf 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 213 
 
 - 
 ii Irlli If 
 
214 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 OPERATING DATA FOR SWITCH MACHINES 
 
 
 
 Operating 
 
 
 
 Time 
 
 Function Operated 
 
 Operating 
 Current 
 
 Using 
 Maximum 
 Length 
 
 
 
 Control 
 
 
 
 Wires 
 
 
 Amp. 
 
 Seconds 
 
 Switch Machine, Model 2, Switch or Derail, . . . 
 
 6.0 
 
 2 
 
 Switch Machine, Model 2, Double Slip or M. P. 
 
 
 
 Frog . . 
 
 10.0 
 
 2.2 
 
 Switch Machine, Model 4A, Switch or Derail, . . . 
 
 4.5 
 
 3 
 
 Switch Machine, Model 4A, Double Slip or M. P. 
 
 
 
 Frog, 
 
 7.0 
 
 3.2 
 
 Switch Machine, Model 4B, Switch or Derail,. . . 
 
 4.5 
 
 3 
 
 Switch Machine, Model 4B, Double Slip or M. P. 
 
 
 
 Frog . . . 
 
 7.0 
 
 3.2 
 
 
 
 
 FIG. 156. DIAGRAM SHOWING COMPARATIVE CLEARANCES OF MODEL, 2 
 
 AND MODEL 4 SWITCH MACHINE 
 
 Normal location. 
 
 
 DIMENSION A MODEL 2 SWITCH MACHINE 
 
 Rail Section 
 
 (See Note.) 
 
 
 A. R. A. Type A. 
 
 A. R. A. Type B. 
 
 A. S. C. E. 
 
 Lbs. per Yd. 
 
 Inches 
 
 Inches 
 
 Inches 
 
 60 
 
 22% 
 
 21 
 
 21% 
 
 70 
 
 23% 
 
 22% 6 
 
 228/4 
 
 80 
 
 24% 
 
 24 
 
 24% 
 
 90 
 
 26% 
 
 25% 6 
 
 25% 
 
 100 
 
 28% 
 
 26i% 
 
 27% 
 
 NOTE. Dimension A is the distance from gauge side of rail to point on 
 cover of Model 2 switch machine equal to height of rail used. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 215 
 
 FIG. 157. DIAGRAM SHOWING CLEARANCE BETWEEN TOP OF MODEL 4 
 
 SWITCH MACHINE AND CONTACTING SURFACE OF THIRD RAIL. 
 
 ELECTRIC DIVISION, N. Y. C. & H. R. R. R. 
 
 
 Ij^fepj^ 
 
 jr 
 
 
 ( 
 
 J h 
 
 I I 
 
 
 J 
 
 
 
 / 
 
 
 
 
 t 
 
 FIG. 158. DIAGRAM SHOWING CLEARANCE BETWEEN TOP OF MODEL 4 
 
 SWITCH MACHINE AND CONTACTING SURFACE OF THIRD RAIL, 
 
 LONG ISLAND R. R. 
 
216 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 . I F"'T--''..fT7.ii6 
 
 \ Circular loom/ 
 
 ;oj '-* " ' j. Conn etion, j> "10100 
 
 "** ^io; ~-3y>--^ C 
 
 Fio. 159. DIMENSIONS OF MODEL 2 SWITCH MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 217 
 
 e'4 i" [- 
 
 FIG. 160. DIMENSIONS OF MODEL 4 SWITCH MACHINE FOR MOVABLE 
 POINT FBOQ OR DOUBLE SLIP SWITCH 
 
 Fio. 161 DIMENSIONS OF MODEL 4 SWITCH MACHINE FOR SINGLE 
 SWITCH OR DERAIL 
 
218 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 (Section A-B) 
 FIG. 162. SINGLE SWITCH OPERATED BY MODEL 4 SWITCH MACHINE 
 
 (Section A-B) 
 FIG. 163. SINGLE SWITCH OPERATED BY MODEL 2 SWITCH MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 219 
 
 (Section A-B) 
 
 FIG. 164. SPLIT POINT DERAIL OPERATED BY MODEL 4 
 SWITCH MACHINE 
 
 (Section A-B) 
 
 Fia. 165. SPLIT POINT DERAIL OPERATED BY MODEL 2 SWITCH 
 MACHINE 
 
220 
 
 GENERAL, RAILWAY SIGNAL COMPANY 
 
 ffi 
 
 2-8 
 
 (Section A-B) 
 FIG. 166. HAYES DERAIL OPERATED BY MODEL 4 SWITCH MACHINE 
 
 (Section A-B) 
 FIG. 167. HAYES DERAIL OPERATED BY MODEL 2 SWITCH MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 221 
 
 (Section A-B) 
 
 FIG. 168. WHARTON OR MORDEN DERAIL OPERATED BY MODEL 4 
 SWITCH MACHINE 
 
 (Section A-B) 
 
 FIG. 169. WHARTON OR MORDEN DERAIL OPERATED BY MODEL 2 
 SWITCH MACHINE 
 
222 GENERAL RAILWAY SIGNAL COMPANY 
 
 (Section A-B) 
 
 FIG. 170. SINGLE SLIP SWITCH OPERATED BY MODEL 4 SWITCH 
 MACHINE 
 
 (Section A-B) 
 
 FIG. 171. SINGLE SLIP SWITCH OPERATED BY MODEL 2 SWITCH 
 MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 223 
 
 (Section A-B) 
 
 FIG. 172. DOUBLE SLIP SWITCH OPEKATED BY MODEL 4 SWITCH 
 MACHINE 
 
 (Section A-B) 
 
 FIG. 173. DOUBLE SLIP SWITCH OPERATED BY MODEL 2 SWITCH 
 MACHINE 
 
224 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 (Section A-B) 
 
 FIG. 174. MOVABLE POINT FROG OPERATED BY MODEL 4 
 SWITCH MACHINE 
 
 (Section A-B) 
 
 FIG. 175. MOVABLE POINT FROG OPERATED BY MODEL 2 SWITCH 
 MACHINE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 225 
 
 
 (Section A-B) 
 
 FIG. 176. MOVABLE POINT FROG (WITH DOUBLE SLIP SWITCH) 
 OPERATED BY MODEL 4 SWITCH MACHINE 
 
 A-- 
 
 
 (Section A-B) 
 
 FIG. 177. MOVABLE POINT FROG (WITH DOUBLE SLIP SWITCH) 
 OPERATED BY MODEL 2 SWITCH MACHINE 
 
226 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 1- 
 
 ^ 
 
 .y o> 
 
 c ^ 
 <n 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 227 
 
 QJ 
 
 <n 
 
228 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 229 
 
 HOOK BOLT 3| 
 
 FIG. 181. E. Z. MOTION PLATE RAIL CLIP, HOOK BOLT TYPE 
 
 FIG. 182. E. Z. MOTION P^ATE RAIL CLIP, WEB BOLT TYPE 
 
 FIG. 183. LONG MOTION 
 PLATE "A" 
 
 FIG. 184. SHORT MOTION 
 PLATE "B" 
 
 DIMENSIONS OF MOTION PLATES "A" AND "B 1 
 
 
 DIMENSIONS IN INCHES 
 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 Type of 
 
 
 
 Distance Mo- 
 
 
 
 Motion 
 Plate 
 
 Overall 
 Length of 
 Motion 
 Plate 
 
 Stroke of 
 Motion 
 Plate 
 
 tion Plate 
 Moves After 
 Total Rise 
 Above Rail 
 
 Total Rise 
 of Motion 
 Plate 
 
 Rise 
 Above 
 Rail 
 
 *A 
 
 9y 2 
 
 6 
 
 2 
 
 1 
 
 % 
 
 tA 
 
 12 
 
 7% 
 
 3Va 
 
 1 
 
 % 
 
 tA 
 
 i2y a 
 
 sy a 
 
 2% 
 
 l 7 /ie 
 
 1%6 
 
 *B 
 
 oy s 
 
 4% 
 
 
 1%2 
 
 2 %2 
 
 tB 
 
 ioy 2 
 
 6 
 
 
 
 Uft 
 
 VA 
 
 * Two rivet holes, f Three rivet holes. 
 
230 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 231 
 
 FIG. 186. DIMENSIONS OF MODEL 5 FORM A SWITCH CIRCUIT 
 CONTROLLER FOR SELECTING SIGNAL CIRCUITS 
 
 Four circuits normal or reverse, or two circuits normal 
 and two reverse. 
 
 FIG. 187. SECTION OF ADJUSTA- 
 BLE CAM FOR MODEL 5 FORM A 
 SWITCH CIRCUIT CONTROLLER (Fio. 
 186). 
 
232 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 188 
 
 Fia. 189 
 
 Fia. 190 
 
 FIG. 191 
 
 Flo. 192 
 
 Fia. 193 
 
 FIG. 194 
 
 CONNECTIONS FROM SWITCH POINT TO SWITCH CIRCUIT CONTROLLER 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 233 
 
 Bridge End Shore End 
 
 FIG. 195. BRIDGE CIRCUIT CLOSER 
 Ten way, controlling ten circuits. 
 
 DIMENSIONS OF BRIDGE CIRCUIT CLOSERS 
 
 
 A 
 
 B 
 
 c 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 L 
 
 M 
 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 6 way 
 
 18* 
 
 6f 
 
 14| 
 
 2 
 
 4* 
 
 1H 
 
 144 
 
 19 
 
 | 
 
 
 7i 
 
 U 
 
 10 way 
 
 26 
 
 7 
 
 221 
 
 8 
 
 4ft 
 
 12ft 
 
 22 
 
 24* 
 
 H 
 
 1 
 
 8J 
 
 41 
 
 12 way 
 
 18* 
 
 lift 
 
 141 
 
 2 
 
 4* 
 
 io 
 
 14* 
 
 19 
 
 ; 
 
 
 7* 
 
 If 
 
 NOTE. Twelve way circuit closer is furnished with two tiers of six con- 
 tacts each. 
 
 OPERATION OF BRIDGE CIRCUIT CLOSER 
 
 The G. R. S. bridge circuit closer with centering device is 
 shown in Fig. 195. In the operation of closing, the bridge 
 end is first caused to approach the shore end with its centering 
 arms thrust forward. When these come into contact with the 
 shore end, the latter is brought into proper alignment, the 
 bridge end continuing its forward movement until they abut ; 
 the blades are then forced to enter the jaws, thus making the 
 desired contact. 
 
 The centering device will take care of any horizontal mis- 
 alignment up to one and one-half inches. When this is 
 apt to be exceeded, the circuit closer should be attached to 
 the rails in such a manner that when the rails are lined up 
 
234 GENERAL RAILWAY SIGNAL COMPANY 
 
 the circuit closer will be affected in a similar manner. The- 
 design of the jaws permits of three-fourths inch movement 
 above or below the normal position. 
 
 The maximum stroke of the driving member is approxi- 
 mately thirteen inches. Using this stroke, the maximum 
 extension of the blades (three and one-half inches) can be 
 secured with a permissible opening of five and three-eighths 
 inches between the bridge and shore ends of the circuit closer ; 
 this forces the blades between the jaws two and three-eighths 
 inches. If required, this distance between the bridge and 
 shore ends may be increased to seven and three-sixteenths 
 inches, which will give a contact extension of one and thir- 
 teen-sixteenths inches and force the blades between the jaws 
 for a distance of three-fourths inch. 
 
 If it is desired to reduce the operating stroke and still retain 
 the maximum contact extension, the maximum opening be- 
 tween the bridge and shore ends must be decreased a propor- 
 tional amount. 
 
SECTION IX 
 
 INSTALLATION AND OPERATING DATA FOR 
 SIGNAL MECHANISMS 
 
 COVERING INSTRUCTIONS FOR IN- 
 STALLATION AND MAINTENANCE, EN- 
 ERGY FIGURES, CLEARANCES RE- 
 QUIRED, DIMENSIONS AND TYPICAL 
 CIRCUITS; ALSO DIMENSIONS OF 
 MASTS, SPECTACLES, BLADES AND 
 FOUNDATIONS 
 
INSTRUCTIONS COVERING THE INSTALLA- 
 TION AND MAINTENANCE OF 
 MODEL 2A SIGNALS 
 
 STORING MECHANISMS 
 
 A*L mechanisms should be stored in an upright position 
 and, if possible, in a dry place, and should not be re- 
 moved from their boxes until they are installed. Avoid 
 disconnecting or removing the motors from the mechanism 
 cases. 
 
 INSTALLATION 
 
 In assemblying mechanisms which are shipped separately 
 from the pole bearings or in reassemblying mechanisms which 
 have been disassembled for any purpose, the surface of all 
 exposed mechanical joints must be cleaned and smoothly 
 coated with white lead before assembly, to insure that they 
 are water-tight. 
 
 Whenever it becomes necessary to bolt a mechanism to its 
 pole bearing, see that the semaphore shaft and mechanism 
 are approximately in their "stop" positions. Then rotate 
 the semaphore shaft backwards and forwards slightly by hand 
 while tightening the bolts, to be sure that no binding takes 
 place during the process. 
 
 When working on a mechanism, the motor door should always 
 be kept closed except when necessary to do work inside of tne 
 motor. 
 
 After a mechanism has been wired, the wire entrance should 
 be sealed to prevent the circulation of air between the inside 
 and outside of the case. Neglect to thoroughly seal may 
 result in trouble due to the probable accumulation of frost 
 or dirt on the circuit breaker parts. If conduit is used be- 
 tween the mechanism case and the pole, the wire entrance 
 or conduit should be likewise sealed. 
 
 ADJUSTMENTS 
 
 All signals are properly adjusted before shipment, the only 
 adjustments ordinarily required in the field being those due to 
 differences in the semaphore spectacles as follows: if the 
 blade is not horizontal when in its stop position, it can be 
 brought to such position by means of adjusting screw A (see 
 Fig. 197). Spring C, adjusted by screw D, should hold block 
 B firmly against screw A, due allowance being made in the 
 spring adjustment for any increase in weight of the signal 
 arm, due to an accumulation of ice or sleet. Fig. 197 shows 
 relation of adjusting screws, spring, block, etc., when used 
 with upper quadrant signals; this will be reversed when ap- 
 plied to lower quadrant signals. 
 
 Having adjusted the blade to the horizontal position, the 
 circuit breaker frame should, if necessary, be rotated bodily 
 
238 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 239 
 
 a sufficient amount to cause the blade to assume its exact 
 forty-five or ninety degree position in operation. 
 
 Individual adjustment of the circuit breaker contact springs 
 should not be necessary under ordinary conditions. If required, 
 great care should be exercised to see that all contacts are 
 adjusted to open and close as shown on the circuit plan which 
 accompanies each signal mechanism. 
 
 In replacing a circuit breaker which may have been removed 
 from the mechanism for any cause, great care should be taken 
 to see that the circuit breaker operating segments mesh prop- 
 erly. Otherwise, it will be impossible for the blade to assume 
 
 FIG. 197. SECTION OF CLAMP BEARING SHOWING SEMAPHORE 
 SPECTACLE ADJUSTMENT 
 
 its proper positions in operation except by extreme adjustment 
 of the contacts and circuit breaker. 
 
 LUBRICATION 
 
 See that all moving parts are thoroughly lubricated with 
 oil that will not thicken in cold weather or dry up in hot 
 weather. "Hydrol," "Polar Ice," or "3 in One" oils have 
 been found satisfactory. Use an oil can with a nine inch 
 curved spout. 
 
 After lubrication, the signals should be operated several 
 times, in order to work the oil thoroughly into the bearings. 
 The word " oil " on the diagram, Fig. 196, will indicate what 
 parts require lubrication. If the mechanism has become 
 rusty, especial care should be taken to see that all parts 
 are operating freely before attempting to put the signal in 
 service. 
 
240 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TESTS 
 
 If the signal has been properly adjusted and lubricated it 
 will operate freely. If in doubt as to whether a signal is 
 sufficiently free in operation, a drop-away test should be 
 made as follows. Connect an adjustable resistance in series 
 with the motor. Gradually reduce it until the motor will just 
 move the blade upwards. Just before reaching the forty-five 
 degree position, quickly insert sufficient resistance to just 
 
 APPLY VASOJNE TO LOCK DOG 
 ONCE A YEAR 
 
 OiL 
 
 FIG. 198. OILING DIAGRAM FOR MODEL, 2A DWARF BEARING 
 
 permit the motor to start backwards, moved by the weight of 
 the blade grip. The current which will permit it to start 
 backwards from a given position should be approximately 
 50 per cent, of the current required to move it up to 
 that position. The same process should be repeated in the 
 ninety degree position or sixty degree, as the case may be. 
 
 The signal having been oiled and operated a few times, see 
 that the blade snubs properly in descending and also that the 
 ratcheted main gear (F, Figs. 52 and 56) clicks approximately 
 three or four times in so doing. The number of clicks can be 
 regulated by the adjusting screw on the ratcheted main gear. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 241 
 
 MAINTENANCE 
 
 Ordinarily in maintaining a signal, the only requirements 
 are that the connections be kept tight, contacts clean, and the 
 mechanism suitably oiled and cleaned. 
 
 Avoid disturbing the commutator or brushes in any way 
 unless found necessary. A commutator in good condition will 
 have a dark glossy appearance. If, however, it should be- 
 come dirty, it should be cleaned by chamois skin moistened 
 with oil, any surplus oil to be wiped off of the commutator by 
 a dry piece of chamois. 
 
 Use a chamois skin in cleaning the circuit breaker contacts. 
 
 If it should become necessary to put a new brush into a 
 motor, the brush should, after having been put in position, be 
 seated to the commutator by drawing thin fine sandpaper 
 under the brush while the brush is being pressed against the 
 commutator. The smooth side of the sandpaper should be 
 against the commutator. Use "00 Single Finishing Flint 
 Sandpaper." 
 
 OPERATING DATA FOR SIGNALS 
 
 
 
 
 Operating 
 
 
 
 
 Time 
 
 Function Operated 
 
 Operating 
 Current 
 
 Holding 
 Current 
 
 Using 
 Maximum 
 Length 
 
 
 
 
 Control 
 
 
 
 
 Wire 
 
 
 Amp. 
 
 Amp. 
 
 Seconds 
 
 High Signal, Model 2 
 
 3.0 
 
 .14 
 
 4 
 
 High Signal, Model 3 or 7, 
 
 3.0 
 
 .11 
 
 3 
 
 High Signal, Model 2A, 
 
 .82 
 
 .25 
 
 6 
 
 Dwarf Signal, Model 2A, . . . 
 
 .82 
 
 .25 
 
 4 
 
 Dwarf Signal, Model 2 or 3 
 
 4.0 
 
 .17 
 
 1 
 
242 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 243 
 
 Note, OneU')mch maximum variation 
 
 ett\r nay on total height of ma st 
 
 Bottom of 5' Pipe 
 
 - Top O f BrdcK et p M t. or top chord of Bridj* - 
 
 note; Distance betneen center of pole and vertical center of shaft to be 
 not les than 3| nor more than 4|". 
 
 FIG. 200. BRACKET POST AND BRIDGE SIGNAL MASTS 
 R,. S. A. drawing 1037, dated 1910. 
 
 Mote,; Tno (.2) inches maximum variation aliened 
 either nay on total height of mast. 
 
 -not* 
 
 Mote; Distance betneen center of pole and vertical center of shaft to be 
 not less than 3|"nor more than 4|" 
 FIG. 201. GROUND SIGNAL MASTS 
 R. S. A. drawing 1035, dated 1910. 
 
244 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 am, 
 
 GAUGE or TRACKS is 4-9" 
 WHIN GAUSE or TRACKS is -4- 
 
 THE CLEARANCE BETWEEN SIGNAL 
 AND MAXIMUM EQUIPMENT LINE WILL 
 BE i" GREATER. 
 
 FIG. 202. DIAGRAM SHOWING CLEARANCE BETWEEN MODEL, 2A DWARF 
 SIGNAL AND THIRD RAIL. ELECTRIC DIVISION, 
 N. Y. C. & H. R. R. R. 
 Twelve foot track centers. 
 
 FIG. 203. 
 
 METHOD OF TAPING WIRES RUNNING FROM MAST 
 TO SIGNAL MECHANISM (see Fig. 199) 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 245 
 
 FIG. 204. DIMENSIONS OP MODEL 2A THREE POSITION, NON-AUTOMATIC 
 DWARF SIGNAL, EQUIPPED WITH ELECTRIC LAMP 
 
 Fio. 205. DIMENSIONS OF MODEL 2A Two POSITION, NON-AUTOMATIC 
 
 DWARF SIGNAL, EQUIPPED WITH OIL LAMP 
 Spectacle R. S. A. drawing 1233, October, 1912. 
 
246 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 [ ".*! } I I t"r*~~ ">"["'" 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 247 
 
 01 Shalt 
 
 FIG. 207. DIMENSIONS OF ONE ARM MODEL 2 SOLENOID 
 
 DWARF SIGNAL 
 Spectacle R. S. A. drawing 1233, October, 1912. 
 
 9j" J T <fc of shaft 
 
 Fio. 208. DIMENSIONS OF MODEL 3 SOLENOID DWARF SIGNAL 
 Spectacle R. S. A. drawing 1233, October, 1912. 
 
248 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 I* S^. Straight Hole 
 
 FIG. 209. SEMAPHORE SPECTACLE 
 R. S. A. Design "A," drawing 1040, October, 1912. 
 
 FIQ. 210. SEMAPHORE SPECTACLE 
 R. S. A. Design "B," drawing 1041, October, 1912. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 249 
 
 Max. Metal Cleat 
 
 '*! 
 
 
 -4V 
 
 r^-ioH 
 
 i 
 
 r- 
 
 . * j. 
 
 
 ^=fc 
 
 ' 
 
 ^f 
 
 ^ S in 
 
 bt 
 
 ; 
 
 u> 
 
 i'Bolts 
 
 "lOlGO 
 
 1 
 
 r 
 
 ^ 
 
 Taper i: 
 
 16 
 
 I_ 
 
 FIQ. 211 
 
 *M. Max. Metal Cleat 
 
 FIG. 212 
 
 *I4 Max. Metal Cleat 
 
 Fro. 213 
 BLADES FOR UPPER QUADRANT SIGNALS 
 
 R. S. A. drawing 1065, dated 1911. 
 Where stripes are used the dimensions shown are recommended. 
 
250 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TORQUE CURVES FOR R. S. A. DESIGN "A" 
 
 SEMAPHORE SPECTACLE 
 R. S. A. plan 1064. Issue December, 1912. 
 
 NOTE: FULL LINES wstsetrr TORQUE POP SPECTACLE MOVSMEWTS TO 90 [STOP TO PROCEED] 
 
 DOTTED LINES REPRESENT TORQUE FOR SPECTACLE MOVEMENTS 90 TO 0* fPRKEEO TO STOSJ 
 
 
 
 
 60 -- 
 55 
 
 jl 
 
 
 50 
 
 45 - 
 
 jjjjjjjj: 
 
 BLADE PLATE , BOLTS AND 
 3-6 ASH BLADE - WT. S|LBS 
 . . ^ . JB ._ LKT sfMA W|TH 2 | L9 
 S,..; BLADE PLATE, BOLTS AHO 
 
 40 - 
 |35 ,'-2~ 
 
 l-jjijjjj 
 
 * HI II Jamil 
 
 
 - ! b , - - * i, I I . 2-6 ASH BLADE -WT.J^LO 
 - ! N _ _ - , _ x BtAK PLATE , BOLTS AND 
 * - s ' ^ ' )0'= SPECTACLE COMPLETE fcNO 
 
 - ^ * 4=^ " ; ASSUMING BLADE BROKEN 
 " > OFF AT 6RIP. 
 
 ....... ^ EE'= ELECT '^MA. wrrnouT 
 
 ----- BLADE , BLADE PLATE 
 - - . OH BOLTS . 
 
 I 20 jjii:::::; 
 
 15 -/-'-- 
 
 io j 3 ::; :' :: 
 
 5 g < j; Jo.^l.u 
 
 
 ..! - N MINIMUM TORQUE LINE 
 - FOR ELECTRIC SEMAPHORE 
 WITHOUT BLADE OR 
 BLADE FASTENINGS. 
 
 / MAXIMUM MECHANISM 
 
 7 7 1* \ FRICTION LINE . 
 
 &M&& 
 
 10 20 30 40 45 50 60 70 80 90 
 DECREES 
 
 
 
 h /; %$^ l - 
 
 "" 
 
 
 ^Mf-Hr^R^ 
 
 
 \ju^ |A 
 
 
 NOTE*. SPECTACLE EQUIPPED WITH g ROUNDELS AND RETAINING MN6S IN ALL CASES. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 251 
 
 MOTE; ZO" for Pipe Bracket Post. 
 
 22" (or Channel Column Bracket Post. 
 
 FIG. 215. BRACKET POST FOUNDATION 
 
 R. S. A. drawing 1108, dated 1909. 
 
 (70.3 cubic feet of concrete.) 
 
252 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Fio. 216. GROUND SIGNAL MAST FOUNDATION 
 
 R. S. A. drawing 1107, dated 1909. 
 
 (30.25 cubic feet of concrete.) 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 253 
 
 J_l16 Bolt* Hot 
 
 FIG. 217. DWARF SIGNAL FOUNDATION FOR MODEL 2A, 
 MODEL 3 OR ONE ARM MODEL 2 DWARF SIGNAL 
 (6.5 cubic feet of concrete.) 
 
 3 3- 
 3 9"- 
 -5 0"- 
 
 i 
 
 T- 
 1 
 
 FIG. 218. DWARF SIGNAL FOUNDATION FOR Two ARM 
 
 MODEL 2 DWARF SIGNAL 
 (11.25 cubic feet of concrete.) 
 
254 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 255 
 
 ler 
 
256 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 ^0 '(0 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 257 
 
258 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 259 
 
260 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 I 
 
 o 
 
 
 en 
 di 
 
 0) 
 
 c 
 
 O 
 
 O 
 
 s 
 ? 
 
 5 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 261 
 
262 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 
SECTION X 
 
 INSTALLATION AND OPERATING DATA FOR 
 RELAYS AND INDICATORS 
 
 GIVING ENERGY FIGURES FOR, AND 
 DIMENSIONS OF, THE D. C. AND A. C. 
 RELAYS AND INDICATORS USED IN 
 TRACK AND LINE WORK; ALSO DI- 
 MENSIONS OF RELAY BOXES 
 
RELAYS AND INDICATORS 
 
 ENERGY DATA FOR MODEL 1, D.C. RELAYS 
 
 Resistance Ohms 
 
 Mil. Amps. 
 
 Volts 
 
 4 
 
 110 
 
 .425 
 
 5 
 
 98 
 
 .475 
 
 9 
 
 80 
 
 .7 
 
 16 
 
 62 
 
 1.0 
 
 25 
 
 52 
 
 1.275 
 
 30 
 
 47 
 
 1.4 
 
 35 
 
 44 
 
 1.5 
 
 50 
 
 35 
 
 1.8 
 
 100 
 
 26 
 
 2.5 
 
 300 
 
 15.5 
 
 4.5 
 
 500 
 
 13 
 
 6.5 
 
 800 
 
 11 
 
 9.0 
 
 1000 
 
 10.5 
 
 10.5 
 
 NOTE. Values given in above table are the mimimum on which the 
 relay will operate. Add 10 per cent, for practical operation. Drop away 
 current equals 23 per cent, of minimum operating current. 
 
 ENERGY DATA FOR STYLE A, D.C. INDICATORS 
 FOUR WAT. 
 
 Resistance Ohms 
 
 Mil. Amps. 
 
 Volts 
 
 4 
 
 147 
 
 .59 
 
 5 
 
 135 
 
 .675 
 
 12 
 
 97 
 
 ' 1.16 
 
 38 
 
 56 
 
 2.13 
 
 50 
 
 49 
 
 2.45 
 
 75 
 
 41 
 
 3.10 
 
 100 
 
 37 
 
 3.70 
 
 200 
 
 31 
 
 6.20 
 
 250 
 
 27 
 
 6.75 
 
 500 
 
 18 
 
 9.00 
 
 1000 
 
 14 
 
 14.00 
 
 NOTE. Values given in above table are the minimum on which the 
 indicator will operate. Add 10 per cent, for practical operation. Drop 
 away current equals 33 per cent, of minimum operating current. 
 
266 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIQ. 228. MODEL 9, D.C. RELAY, SHELF TYPE 
 
 FIG. 229. MODEL 9, D. C. RELAY, WALL TYPE 
 
 DIMENSIONS OF MODEL 9 D. C. RELAYS 
 
 Name 
 
 No. of 
 
 Fingers 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 Model 9 Form A4 Neutral Relay, . . . 
 
 4 
 
 6A 
 
 7A 
 
 9 
 
 
 
 Model 9 Form A6 Neutral Relay, . . . 
 
 6 
 
 81% 
 
 7ft 
 
 9 
 
 
 
 Model 9 Form A8 Neutral Relay, . . . 
 
 8 
 
 lOtf 
 
 7A 
 
 9 
 
 
 
 Model 9 Form C4 Neutral Relay, . . . 
 
 4 
 
 6A 
 
 7ft 
 
 9 
 
 
 
 Model 9 Form A4 Neutral Wall Relay, . 
 
 4 
 
 61 
 
 6ft 
 
 8* 
 
 5 
 
 ii 
 
 Model 9 Form A6 Neutral Wall Relay, . 
 
 6 
 
 8 
 
 6ft 
 
 8* 
 
 5| 
 
 4i 
 
 Model 9 Form A4 Polarized Relay, . . . 
 
 4 
 
 6A 
 
 7ft 
 
 9 
 
 
 
 Model 9 Form A6 Polarized Relay, .. . . 
 
 6 
 
 8A 
 
 7ft 
 
 9 
 
 
 
 Model 9 Form A4 Polarized Wall Relay, 
 
 4 
 
 6J 
 
 6ft 
 
 8* 
 
 5f 
 
 4i 
 
 Model 9 Form A6 Polarized Wall Relay, 
 
 6 
 
 8 
 
 6ft 
 
 8* 
 
 5i 
 
 4* 
 
 Model 9 Interlocking Relay, 
 
 
 6& 
 
 12*i 
 
 8 
 
 
 
 
 
 
 
 
 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 267 
 
 ENERGY DATA FOR 
 MODEL 9, D. C. RELAYS 
 
 Resistance 
 Ohms. 
 
 4 WAY 
 
 6 WAT 
 
 8 WAT 
 
 Mil. 
 Amps. 
 
 Volts 
 
 Mil. 
 
 Amps. 
 
 Volts 
 
 Mil. 
 
 Amps. 
 
 Volts 
 
 3.5 
 
 79 
 
 .28 
 
 95 
 
 .34 
 
 Ill 
 
 .39 
 
 4 
 
 75 
 
 .30 
 
 90 
 
 ,36 
 
 105 
 
 .42 
 
 4.2 
 
 71 
 
 .30 
 
 85 
 
 .36 
 
 100 
 
 .42 
 
 5 
 
 71 
 
 .36 
 
 85 
 
 .43 
 
 100 
 
 .50 
 
 6 
 
 64 
 
 .38 
 
 76 
 
 .46 
 
 85 
 
 .51 
 
 7 
 
 57 
 
 .40 
 
 69 
 
 .49 
 
 81 
 
 .57 
 
 9 
 
 53 
 
 .48 
 
 64 
 
 .58 
 
 75 
 
 .68 
 
 10 
 
 51 
 
 .51 
 
 61 
 
 .61 
 
 72 
 
 .72 
 
 11 
 
 47 
 
 .52 
 
 56 
 
 .62 
 
 66 
 
 .73 
 
 12 
 
 51 
 
 .61 
 
 61 
 
 .73 
 
 72 
 
 .87 
 
 16 
 
 41 
 
 .66 
 
 49 
 
 .79 
 
 57 
 
 .92 
 
 17 
 
 38 
 
 .65 
 
 46 
 
 .79 
 
 54 
 
 .92 
 
 20 
 
 38 
 
 .76 
 
 46 
 
 .93 
 
 54 
 
 .08 
 
 26 
 
 31 
 
 .81 
 
 37 
 
 .97 
 
 44 
 
 .15 
 
 35 
 
 31 
 
 1.08 
 
 37 
 
 1.30 
 
 44 
 
 .54 
 
 40 
 
 27 
 
 1.08 
 
 33 
 
 1.32 
 
 38 
 
 .52 
 
 46 
 
 24 
 
 1.11 
 
 29 
 
 1.34 
 
 34 
 
 .57 
 
 50 
 
 23 
 
 1.15 
 
 27 
 
 1.35 
 
 32 
 
 .60 
 
 60 
 
 21 
 
 1.26 
 
 25 
 
 1.50 
 
 30 
 
 .80 
 
 68 
 
 20 
 
 1.36 
 
 24 
 
 1.64 
 
 28 
 
 .91 
 
 75 
 
 21 
 
 1.57 
 
 26 
 
 1.95 
 
 29 
 
 2.18 
 
 80 
 
 20 
 
 1.60 
 
 25 
 
 2.00 
 
 29 
 
 2.32 
 
 90 
 
 18 
 
 1.62 
 
 23 
 
 2.07 
 
 27 
 
 2.43 
 
 98 
 
 17 
 
 1.67 
 
 21 
 
 2.06 
 
 25 
 
 2.45 
 
 125 
 
 15 
 
 1.88 
 
 18 
 
 2.25 
 
 21 
 
 2.63 
 
 150 
 
 14 
 
 2.10 
 
 16 
 
 2.40 
 
 19 
 
 2.85 
 
 200 
 
 13 
 
 2.60 
 
 16 
 
 3.20 
 
 18 
 
 3.60 
 
 244 
 
 11 
 
 2.68 
 
 14 
 
 3.42 
 
 16 
 
 3.91 
 
 300 
 
 11 
 
 3.30 
 
 13 
 
 3.90 
 
 15 
 
 4.50 
 
 346 
 
 10 
 
 3.46 
 
 12 
 
 4.15 
 
 14 
 
 4.85 
 
 400 
 
 10 
 
 4.00 
 
 12 
 
 4.80 
 
 14 
 
 5.60 
 
 500 
 
 8.5 
 
 4.25 
 
 10 
 
 5.00 
 
 12 
 
 6.00 
 
 516 
 
 8.5 
 
 4.39 
 
 10 
 
 5.16 
 
 i2 
 
 6.19 
 
 600 
 
 8.5 
 
 5.10 
 
 10 
 
 6.00 
 
 12 
 
 7.20 
 
 670 
 
 7.5 
 
 5.02 
 
 9 
 
 6.03 
 
 11 
 
 7.37 
 
 800 
 
 8 
 
 6.40 
 
 9.3 
 
 7.44 
 
 11 
 
 8.80 
 
 900 
 
 7.5 
 
 6.75 
 
 8.5 
 
 7.65 
 
 10 
 
 9.00 
 
 1000 
 
 7 
 
 7.00 
 
 8 
 
 8.00 
 
 9 
 
 9.00 
 
 1500 
 
 6 
 
 9.00 
 
 7 
 
 10.5 
 
 8 
 
 12.00 
 
 1600 
 
 5.5 
 
 8.80 
 
 6.5 
 
 10.40 
 
 7.5 
 
 12.00 
 
 
 
 
 
 
 
 
 NOTE. Values given in 
 will operate. Add 10 per 
 rent equals 40 per cent, of 
 
 above table are the minimum on which the ielay 
 cent, for practical operation. Drop away cur- 
 minimum operating current, 
 
268 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Fia. 230. MODEL 9, D. C. INDICATORS 
 
 FIG. 231. THREE POSITION D. C. MOTOR RELAY 
 
 This relay requires the same amount of energy for operation as the 
 Model 9, D. C. Relay. Drop away current equals 50 per cent, of normal 
 operating current. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 269 
 
 ENERGY DATA FOR 
 MODEL 9, D. C. INDICATORS 
 
 Resis. 
 
 TOWER INDICATORS 
 
 SWITCH 
 INDICATOR 
 
 4 Way 
 
 6 Way 
 
 8 Way 
 
 Ohms 
 
 Mil. 
 Amps. 
 
 Volts 
 
 Mil. 
 Amps. 
 
 Volts 
 
 MIL 
 
 Amps, 
 
 Volts 
 
 Mil. 
 Amps. 
 
 Volts 
 
 4 
 
 101 
 
 .40 
 
 107 
 
 .43 
 
 113 
 
 .45 
 
 101 
 
 .40 
 
 4.4 
 
 94 
 
 .42 
 
 100 
 
 .44 
 
 106 
 
 .47 
 
 94 
 
 .42 
 
 6.8 
 
 75 
 
 .51 
 
 79 
 
 .54 
 
 83 
 
 .56 
 
 75 
 
 .51 
 
 9 
 
 66 
 
 .60 
 
 70 
 
 .63 
 
 74 
 
 .66 
 
 66 
 
 .60 
 
 9.2 
 
 65 
 
 .60 
 
 69 
 
 .63 
 
 73 
 
 .67 
 
 65 
 
 .60 
 
 14 
 
 55 
 
 .77 
 
 58 
 
 .82 
 
 61 
 
 .85 
 
 55 
 
 .77 
 
 20 
 
 45 
 
 .90 
 
 48 
 
 .97 
 
 51 
 
 1.02 
 
 45 
 
 .90 
 
 22 
 
 44 
 
 .96 
 
 47 
 
 1.03 
 
 50 
 
 1.10 
 
 44 
 
 .96 
 
 30 
 
 37 
 
 1.11 
 
 39 
 
 1.18 
 
 41 
 
 1.23 
 
 37 
 
 1.11 
 
 34 
 
 35 
 
 1.19 
 
 37 
 
 1.26 
 
 39 
 
 1.33 
 
 35 
 
 1.19 
 
 40 
 
 30 
 
 1.20 
 
 32 
 
 1.28 
 
 34 
 
 1.36 
 
 30 
 
 1.20 
 
 50 
 
 29 
 
 1.45 
 
 31 
 
 1.55 
 
 33 
 
 1.65 
 
 29 
 
 1.45 
 
 56 
 
 27 
 
 1.51 
 
 29 
 
 1.62 
 
 31 
 
 1.73 
 
 7 
 
 1.51 
 
 92 
 
 24 
 
 2.20 
 
 26 
 
 2.39 
 
 28 
 
 2.57 
 
 24 
 
 2.20 
 
 100 
 
 22 
 
 2.20 
 
 23 
 
 2.30 
 
 25 
 
 2.50 
 
 22 
 
 2.20 
 
 130 
 
 19 
 
 2.47 
 
 20 
 
 2.60 
 
 21 
 
 2.73 
 
 19 
 
 2.47 
 
 200 
 
 15 
 
 3.00 
 
 16 
 
 3.20 
 
 17 
 
 3.40 
 
 15 
 
 3.00 
 
 300 
 
 13 
 
 3.90 
 
 14 
 
 4.20 
 
 15 
 
 4.50 
 
 13 
 
 3.90 
 
 500 
 
 11 
 
 5.50 
 
 12 
 
 6.00 
 
 13 
 
 6.50 
 
 11 . 
 
 5.50 
 
 690 
 
 8.5 
 
 5.86 
 
 9 
 
 6.21 
 
 9.5 
 
 6.55 
 
 8.5 
 
 5.86 
 
 1000 
 
 7.5 
 
 7.50 
 
 8 
 
 8.00 
 
 8.5 
 
 8.50 
 
 7.5 
 
 7.50 
 
 NOTE. Values given in above table are the minimum on which the 
 indicator will operate. Add 10 per cent, for practical operation. Drop 
 away current equals 33 per cent, of minimum operating current. 
 
270 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 t^Nij 
 
 7'/8- 
 
 FIG. 232. RELAY WALL OR SHELF TYPE 
 
 f ~ 
 
 FIG. 233. TOWER INDICATOR 
 
 4f- 
 
 FIG. 234. INDICATING RELAY 
 
 MODEL 2 FORM B, MODEL 3 FORM B, OR MODEL Z FORM B, A. C. 
 RELAYS AND INDICATORS 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 271 
 
 ENERGY DATA FOR A. C. LINE RELAYS AND INDICATORS 
 FOB USE ON 55-110 OR 220 VOLTS, 25 OR 60 CYCLES. 
 
 
 
 MAXIMUM ENERGY REQUIRED AT NORMAL 
 
 
 
 VOLTAGE (SEE NOTE) 
 
 Name of Device 
 
 Cycles 
 
 2 Position 
 
 3 Position 
 
 
 
 Split Phase 
 
 Local 
 
 Line 
 
 
 
 V. A. 
 
 Watts 
 
 V. A. 
 
 Watts 
 
 V. A. 
 
 Watts 
 
 Model 2 Form A Line ] 
 
 
 
 
 
 
 
 
 Relays, with 6 front, 
 
 
 
 
 
 
 
 
 6 back or 12 front con- 
 
 25 
 
 12.0 
 
 10.0 
 
 7.8 
 
 5.4 
 
 6.4 
 
 5.4 
 
 tacts, and indicating 
 
 60 
 
 12.0 
 
 10.0 
 
 7.8 
 
 5.4 
 
 6.4 
 
 5.4 
 
 attachment for tower 
 
 
 
 
 
 
 
 
 use, 
 
 
 
 
 
 
 
 
 Model 2 Form B Line ] 
 
 
 
 
 
 
 
 
 Relays, with 6 front, 
 2 back contacts, and ^ 
 indicating attach- 
 
 25 
 60 
 
 15.0 
 15.0 
 
 10.0 
 10.0 
 
 11.7 
 11.7 
 
 5.4 
 5.4 
 
 6.5 
 6.5 
 
 % 
 5.4 
 5.4 
 
 ment for tower use, . J 
 
 
 
 
 
 
 
 
 Model Z Form B Line ] 
 
 
 
 
 
 
 
 
 Relays, with 6 front, 
 2 back contacts, and ^ 
 indicating attach- 
 
 25 
 60 
 
 5.5 
 10.0 
 
 2.0 
 3.0 
 
 
 
 
 
 ment for tower use, . j 
 
 
 
 
 
 
 
 
 Model 2 Form B Switch | 
 Indicator, without > 
 contacts, ) 
 
 25 
 60 
 
 15.0 
 15.0 
 
 10.0 
 10.0 
 
 
 ... 
 
 
 
 Model Z Form B Switch 
 Indicator, without >- 
 
 25 
 60 
 
 3.0 
 5.5 
 
 1.5 
 
 1.8 
 
 
 
 
 
 contacts, ) 
 
 
 
 
 
 
 
 
 Model 2 Form B Tower 
 Indicator, without V 
 contacts . j 
 
 25 
 60 
 
 15.0 
 15.0 
 
 10.0 
 10.0 
 
 
 
 
 
 Model Z Form B Tower 
 Indicator, without > 
 
 25 
 AH 
 
 3.0 
 
 5C 
 
 15 
 
 10 
 
 
 
 
 
 contacts, ) 
 
 OU 
 
 . D 
 
 . . o 
 
 
 
 
 
 
 
 
 
 
 
 
 NOTE. Above energy figures will permit practical operation of these de- 
 vices on a voltage 20 per cent, below normal and are based on a maximum 
 
 equipment of contacts, including indicating attachment for tower use. 
 Without indicating attachment, with a lesser number of contacts, by spe- 
 
 cial construction, or by combinations of any of the foregoing, the above 
 
 energy may be reduced 20 to 50 per cent. Re" 
 
 less than 50 per cent, of the minimum operating energy. 
 
 may be reduced 20 to 50 per cent. Relay must drop away on not 
 
 NOTE. The above table permits the following line resistance in series 
 with line phase of relay. 
 
 Volts 
 
 Cycles 
 
 Resistance (Ohms) 
 
 55 
 
 25 
 
 75 
 
 55 
 
 60 
 
 100 
 
 110 
 
 25 
 
 150 
 
 110 
 
 60 
 
 200 
 
 220 
 
 25 
 
 250 
 
 220 
 
 60 
 
 300 
 
272 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 8^8- 4 Nay 
 
 FIG. 235. MODEL 2 FORM A 
 POLYPHASE RELAT 
 
 FIG. 236. MODEL 2 FORM A 
 
 POLYPHASE INDICATING 
 
 RELAY 
 
 FIG. 237. 
 
 SIDE VIEW OF MODEL 2 FORM A POLYPHASE 
 RELAY OR INDICATING RELAY 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 273 
 
 OPERATION OF THE MODEL 2 FORM A REGULAR POLY- 
 PHASE RELAY, IN CONNECTION WITH DOUBLE RAIL 
 A. C. TRACK CIRCUITS ON ELECTRIFIED 
 DIRECT CURRENT ROADS 
 
 POHtR LIME 
 
 TwwvJ 
 
 n G* 
 
 TRAHSrORMER 
 VOLT AMPERES TOR CURVES MEASURED AT THESE POIMT5 
 
 MODEL Z FORM A RELAY 
 IMPEDANCE BOND IMPEDANCE 
 
 FIG. 238. END FED DOUBLE RAIL A. C. TRACK CIRCUIT 
 
 VOLT-AMPERES 
 
 too 
 
 ) 1000 ZOOO 3000 4000 5000 6000 7000 8000 9000 
 
 LENGTH OF TRACK CIRCUIT IN FEET 
 
 FIG. 239. CURVE SHOWING ENERGY REQUIRED FOR 
 OPERATION ON 25 CYCLE CURRENT 
 
 VOLT-AM PE 
 150 
 
 1?5 
 100 
 75 
 50 
 25 
 n 
 
 RES 
 
 
 
 
 
 
 
 
 I 
 
 \ \ 
 
 
 / 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 AVER0 
 
 GE BALLAST^ 
 
 k/ 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 L>^| # 
 
 
 ^ 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 
 
 
 
 
 
 
 M 
 
 *=i 
 
 
 
 ** 
 
 ^ss 
 
 e= 
 
 Z 
 
 *-~~* 
 
 ^GOOD BALLAST 
 
 TTT 
 
 
 
 
 
 
 1000 ZOOO 3000 4000 5000 6000 7000 8000 9000 
 
 LENGTH OF TRACK CIRCUIT IN FEET 
 
 FIG. 240. CURVE SHOWING ENERGY REQUIRED FOR 
 OPERATION ON 60 CYCLE CURRENT 
 
 NOTE. Volt amperes shown in Figs. 239 and 240 are the total of the volt 
 amperes fed to the track circuit and to the relay local. Relay is equipped 
 with four front and two back contacts. Curves are based on 85 pound 
 rail being used. 
 
 Good ballast (approximately 10 ohms per 1,000 ft.) consists of rock or 
 gravel ballast, well drained and free from the base of the rails. 
 
 Average ballast (approximately 5 ohms per 1,000 ft.) consists of a ballast, 
 such as a well drained gravel ballast, covering the base of the rails. 
 
 Dirt, cinder or badly drained gravel ballast, covering the base of the rails, 
 is considered poor and necessitates the use of much more energy for the 
 operation of track circuits than is shown in the curves. 
 
274 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TABLE SHOWING RELATIVE AMOUNT OF ENERGY RE- 
 QUIRED FOR MODEL 2 FORM A TRACK RELAYS, 
 REGULAR AND QUICK ACTING, WITH DIF- 
 FERENT CONTACT COMBINATIONS 
 
 Model 2 Form A 
 Track Relays 
 
 Contact Equipment 
 
 Relative Amount 
 of Energy 
 Required 
 
 Regular 
 
 4 front, 2 back, 
 
 1 
 
 Regular, 
 
 2 front, 2 back, . . . 
 
 8 
 
 Regular, 
 Quick Acting, 
 
 6 front, 2 back, 
 2 front, 2 back, . . . 
 
 1.4 
 3 5 
 
 Quick Acting 
 Quick Acting, 
 
 4 front, 2 back, 
 6 front, 2 back, 
 
 3.5 
 4.2 
 
 NOTE. Regular Model 2 Form A relay with four front and two back 
 contacts taken as unity. For energy required by this relay on 25 or 60 
 cycle operation, see curves on page 273. 
 
 MS 
 
 \Z' 
 
 FIG. 241. 
 
 WOOD RELAY Box FOB MODEL 2 FOEM A 
 POLYPHASE RELAYS 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 275 
 
 FIG. 242. 
 
 IRON RELAY Box FOR D. C. RELAYS AND 
 FORM B, A. C. RELAYS 
 
 Fia, 243. WOOD RELAY Box FOR D. C. RELAYS AND 
 FORM B, A. C. RELAYS 
 
276 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 UMPCRE 
 
 tr 
 
 RESISTANCE 100 OHMS 
 
 Pro. 244. CIRCUIT FOR TESTING PICK UP AND DROP AWAY OF 
 D. C. TRACK RELAYS 
 
 RtMSTANCt 100 OHV* 
 
 E VOLTS 
 
 T 
 
 FIG. 245. 
 
 CIRCUIT FOR TESTING PICK UP AND DROP AWAY OF 
 D. C. LINE RELAYS 
 
 1 JkMPtRE. RANGE. 
 
 FIG. 246. CIRCUIT FOR TESTING RESISTANCE OF RELAY CONTACTS 
 (Resistance equals voltage divided by current.) 
 
 NOTE. Several readings should be made in above tests and the average 
 taken. 
 
 The resistance used in Figs. 244 and 245 consists of a resistance with a 
 variable center connection. It should, preferably, have uniformly graduated 
 steps. The resistance used in Fig. 246 may merely be a unit of such 
 resistance as to protect the instrument. It is recommended, however, 
 that a variable resistance be used if available. If voltages used in above 
 tests are higher than those indicated, the resistances used will have to be 
 increased accordingly. 
 
 The ammeter for all of the above tests should not have a range greatly 
 exceeding the 1 ampere range indicated above. 
 
SECTION XI 
 
 INSTALLATION AND OPERATING DATA FOR 
 TRANSFORMERS 
 
 COVERING DIMENSIONS AND RATINGS 
 OF LINE AND TRACK TRANSFORMERS 
 
TRANSFORMERS 
 
 FIG. 247 
 DIMENSIONS OF TYPE L LINE TRANSFORMERS 
 
 
 DIMENSIONS (APPROXIMATE) 
 
 Size 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 Q 
 
 H 
 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 1 
 
 13Ao 
 
 12% 
 
 10 
 
 11 
 
 7% 
 
 8% 
 
 2%e 
 
 8 
 
 2 
 
 15H 
 
 13% 
 
 1 l 18 Ae 
 
 1218/16 
 
 8% 
 
 10 
 
 3%o 
 
 8 
 
 3 
 
 17 
 
 15H 
 
 13% 
 
 14% 
 
 10 
 
 11% 
 
 4%6 
 
 8 
 
 FIQ. 248. HANOBR IKONS 
 
280 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 STANDARD RATINGS OF G. R. S. TYPE L TRANSFORMERS 
 
 SIN OLE PHASE, OIL IMMERSED, SELF COOLED, POLE TYPE 
 
 Primary voltage, 2200 25 cycles. 
 
 TOTAL 
 CAPACITY 
 
 SECONDARY LINE WINDINGS 
 
 SECONDARY TRACK WINDINGS 
 
 Size 
 
 V. A. 
 
 No. of 
 Wind- 
 Ings 
 
 V. A. 
 Each 
 
 Volts 
 
 Taps 
 See Note 
 
 No. of 
 Wind- 
 ings 
 
 V. A. 
 
 Each 
 
 Volts 
 
 Taps 
 See Note 
 
 1 
 
 200 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 1 
 
 200 
 
 None 
 
 ... 
 
 .... 
 
 
 (1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 aa Req'd 
 
 1 
 
 400 
 
 1 
 
 400 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 
 
 
 1 
 
 400 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 aa Req'd 
 
 1 
 
 400 
 
 None 
 
 
 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 
 
 
 2 
 
 600 
 
 1 
 
 600 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 2 
 
 600 
 
 1 
 
 400 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 2 
 
 600 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 3 
 
 1000 
 
 1 
 
 1000 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 3 
 
 1000 
 
 1 
 
 800 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 3 
 
 1000 
 
 1 
 
 600 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 NOTE. Terminal board is arranged to take three windings, each to 
 have five terminal posts, which provides for a maximum of three taps 
 per winding. If less than three windings are used, it will be seen that 
 additional posts will be available for taps if same are desired. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 281 
 
 STANDARD RATINGS OF G. R. S. TYPE L TRANSFORMERS 
 
 SINGLE PHASE, OIL IMMERSED, SELF COOLED, POLE TYPE 
 
 Primary voltage, 2200 60 cycles. 
 
 TOTAL 
 CAPACITY 
 
 SECONDARY LINE WINDINGS 
 
 SECONDARY TRACK WINDINGS 
 
 Size 
 
 V. A. 
 
 No. of 
 Wind- 
 ings 
 
 V. A. 
 Each 
 
 Volts 
 
 Taps 
 See Note 1 
 
 No. of 
 Wind- 
 ings 
 
 V. A. 
 Each 
 
 Volts 
 
 Taps 
 See Note 1 
 
 1 
 
 200 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 1 
 
 200 
 
 None 
 
 
 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 1 
 
 400 
 
 1 
 
 400 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 
 
 
 1 
 
 400 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 A 6 V, or 
 
 as Req'd 
 
 1 
 
 400 
 
 None 
 
 ....." 
 
 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 1 
 
 600 
 
 1 
 
 600 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 
 
 
 1 
 
 600 
 
 1 
 
 400 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V. or 
 as Req'd 
 
 1 
 2 
 
 600 
 
 1 
 
 200 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 1000 
 
 1 
 
 1000 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 
 
 
 2 
 
 1000 
 
 1 
 
 800 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 1 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 2 
 
 1000 
 
 1 
 
 600 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 2 
 
 200 
 
 10 
 
 2 & 6 V, or 
 as Req'd 
 
 3 
 
 3000 
 
 1 
 
 3000 
 
 110-220 
 or 
 55-110 
 
 As Req'd 
 
 None 
 
 See 
 Note 
 2 
 
 
 
 
 NOTE 1. Terminal board is arranged to take three windings, each to 
 have five terminal posts, which provides for a maximum of three taps per 
 winding. If less than three windings are used, it will be seen that addi- 
 tional posts will be available for taps if same are desired. 
 
 NpTE 2. Track secondary windings can be placed on the 3,000 V. A. 
 eize if desired. 
 
282 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 249. TYPE K SECONDARY TRACK TRANSFORMER 
 
 STANDARD RATINGS OF G. R. S. TYPE K TRANSFORMERS 
 SINGLE PHASE, AIR COOLED 
 
 25 Cycles 
 
 GO Cycles 
 
 50 V. A. 
 100 V. A. 
 200 V. A. 
 
 50 V. A. 
 100 V. A. 
 200 V. A. 
 
 The above ratings are for 110 volt primary. Ten or twenty volts sec- 
 ondaries can be furnished, equipped with a maximum of six taps when 
 required. 
 
 R. S. A. VOLTAGE RANGES FOR SIGNAL WORK 
 
 (1913) 
 
 (1st Range) Thirty (30) and less. 
 
 (2d Range) Over thirty (30) to and including one hundred 
 and seventy-five (175). 
 
 (3rd Range) Over one hundred and seventy-five (175) to and 
 including two hundred and fifty (250). 
 
 (4th Range) Over two hundred and fifty (250) to and in- 
 cluding six hundred and sixty (660). 
 
 (5th Range) Over six hundred and sixty (660). 
 
SECTION XII 
 
 INSTALLATION AND OPERATING DATA FOR 
 PRIMARY BATTERIES 
 
 COVERING THE CAUbTIC SODA 
 
 CELL, GRAVITY CELL AND DRY 
 
 CELL 
 
PRIMARY BATTERIES 
 
 CAUSTIC SODA PRIMARY CELL 
 
 USES 
 
 THE caustic soda primary battery is largely used on open 
 circuit work, such as for signal operation, where a higner 
 current is required than can be secured from other types 
 of primary batteries without the installation of a great num- 
 ber of cells. A somewhat different design of caustic soda cell 
 is extensively used for track circuit work; although a more 
 expensive cell than the gravity cell, it is one in which the 
 maintenance is very slight, it being ordinarily necessary to 
 make renewals only four or five times a year, this, of 
 course, depending on the type of traffic passing over the 
 section on which the battery is installed. 
 
 DESCRIPTION 
 
 The elements of the cell are of zinc and black oxide of 
 copper and the electrolyte a strong solution of caustic soda 
 and water. These are generally contained in a porcelain or 
 heavy heat resisting glass jar, the latter being preferable due 
 to its freedom from breakage and the ease with which inspec- 
 tion is made. The cut on page 286 gives the appearance of 
 the jar adopted by the R. S. A. as their standard, the ampere 
 hour capacity of this standard cell being 400. 
 
 The elements of the signal cell are generally cast in the 
 form of plates which are suspended from the cover. This 
 cell has an extremely low internal resistance (about .045 ohm) 
 and is hence capable of producing on short circuit the heavy 
 current of 20 amperes. The E. M. F. of the cell is low; when 
 new, it is approximately 0.7 volt and this falls off after the cell 
 has been in service for some time. 
 
 The elements used in the track cell are not necessarily of 
 the same type as those used in the signal cell. One well-known 
 cell used for track circuit work has a zinc element similar in 
 form to the zinc in the gravity cell, the other element being 
 poured loose over a tin disc resting on the bottpm of the jar. 
 The track cell is designed to have an internal resistance of 
 about 0.25 ohm and a current output on short circuit of about 
 2 to 3 amperes. The voltage of the cell is the same as that of 
 the signal cell. 
 
 ACTION OF THE CELL 
 
 When in service, chemical action of the cell gradually dis- 
 solves the zinc element and converts the copper oxide into 
 pure copper. In the case of the signal cell using a copper 
 oxide plate, this change in the element will consist of the 
 reduction of the copper oxide to copper, this reduction taking 
 place from the surface and extending inward; the relative 
 
286 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. SIGNAL CELL 
 
 CAUSTIC SODA PRIMARY BATTERY 
 
 R. S. A. plan 1053. Issue October, 1912. 
 
 (Revision of plan 1053. Issue, 1911.) 
 
 BARREL SHAPE 
 
 HEAT RESISTING 
 GLASS JAR 
 
 NOTES 
 
 THE ASSEMBLED ELEMENT shall be 
 BO arranged that when attached to the 
 cover and the nut on the upper side 
 tightened to place, the element will be 
 at the proper height in the solution. 
 
 Terminal wire shall be No. 12 B & S 
 gauge solid soft drawn copper wire 
 covered with an insulation suitable to 
 withstand the action ol the oil and 
 electrolyte. Insulation on end of 
 wire shall be trimmed either tapered 
 or square and in this operation the 
 wire must not be scored. 
 
 Suspension bolt shall be iron, cop- 
 per plated. 
 
 JAR AND COVER shall conform to 
 the dimensions shown, with reason- 
 able allowance for slight irregularities 
 In manufacture. 
 
 Top of jar shall be square with 
 vertical axis and cover shall be per- 
 fectly flat. 
 
 Manufacturer's name or trade 
 marl? shall be shown on cover. 
 
 Porcelain jars shall be glazed inside 
 and out and covers on top and edge. 
 
 A solution line consisting of a slight 
 ridge or depression extending around 
 the inside of porcelain jars and the 
 outside of glass jars shall be placed 
 as shown. 
 
ELECTRIC INTERLOCKING HANDBOOK 287 
 
 degree of exhaustion of the cell can be ascertained by- 
 scraping off the material from the outside of the plate until 
 the dark copper oxide is exposed. In the cell used for track 
 circuit work, the copper oxide is converted into copper flakes 
 which continue to lie as before on the tin disc in the bottom 
 of the jar. 
 
 CARE OF THE CELL 
 
 In setting up the cell, the jar should be first thoroughly 
 cleaned and then filled with pure water (preferably clear rain 
 water) to such a height that when the elements are added the 
 level of the electrolyte will have been raised to within about 
 one and one-half inches of the top of the jar. The soda 
 should be added slowly and the solution stirred continuously 
 with a stick until the soda is entirely dissolved. Chemical 
 changes raise the temperature of the solution to the boiling 
 point, making it necessary to place ordinary glass, or porcelain 
 jars, on a dry wood surface when mixing the solution, to pre- 
 vent breakage of the jars. The elements should not be placed 
 in the cells until the temperature of the solution has dropped 
 to about 90 degrees Fahr. A thin film of oil should then be 
 poured over the top of the electrolyte to prevent evaporation 
 and "creeping of the salts." 
 
 When mixing the solution, care should be taken not to get 
 the caustic soda dust or solution on one's person, as it is very 
 corrosive ; the best means for counteracting the action of caus- 
 tic soda is water or oil. 
 
 When in service practically no other attention is required 
 by the cell other than an occasional inspection of the elements 
 to determine the degree of exhaustion of the cell. 
 
 The caustic soda solution does not freeze, but when subjected 
 to severe cold the current discharge of the battery is mate- 
 rially reduced, which makes it advisable to furnish protection 
 against extreme temperature conditions where current for 
 operating signal motors is required, or if an equivalent current 
 is wanted for any other purpose. 
 
 EXTRACT FROM R. S. A. SPECIFICATIONS ] FOR 
 CAUSTIC SODA PRIMARY CELL (1911) 
 
 1. GENERAL 
 
 This battery is to be used in the operation of signals, 
 crossing alarms, etc. 
 
 2. MATERIAL 
 
 (a) Railway Signal Association drawing 1053, issue 
 1911, shows tne general design and dimensions of the bat- 
 tery jar, coyer, connections, wire, and that part of the bolt, 
 together with nuts and washers, shown above the cover 
 for supporting the elements. The active part of the cell 
 
288 GENERAL RAILWAY SIGNAL COMPANY 
 
 consists of the zinc, copper oxide, and caustic soda in the 
 granular form, which, mixed with water, forms the solu- 
 tion in which the elements are placed, and a suitable 
 mineral oil, which is used on top of the caustic soda solu- 
 tion to prevent evaporation and the salts from creeping 
 over the top of the jar. 
 
 (6) The assembled element shall consist of the zinc and 
 copper oxide, suitably combined, together with the suspen- 
 sion bolt and terminal wire of sufficient length to extend 
 twelve (12) inches above top of cover. 
 
 3. REQUIREMENTS 
 
 Each complete cell or renewal shall have a capacity of 
 at least four hundred (400) ampere hours, as provided for 
 under test in Section 4. 
 
 4. TEST 
 
 (a) In order to determine the ampere hour capacity of 
 the cell or renewal, one will be selected at random from 
 each lot of one hundred (100), or fraction thereof, and 
 placed on a continuous discharge of one (1) ampere. If 
 the discharge continues four hundred (400) hours without 
 the potential at the terminals of the cell dropping below 
 five-tenths (0.5) of one (1) volt per cell, the cell or renewal 
 will be considered acceptable as far as capacity is concerned. 
 
 (6) One will be selected at random from each lot of one 
 hundred (100), or fraction thereof, and subjected to a dis- 
 charge of three (3) amperes continuously. If, during the 
 first forty (40) hours, the voltage does not drop below 
 fifty-three hundredths (0.53) of one (1) volt and during the 
 next forty (40) hours the voltage does not drop below 
 five-tenths (0.5) of one (1) volt, the cell or renewal will be 
 considered acceptable so far as drop in voltage test is 
 concerned. 
 
 (c) Tests enumerated in paragraphs (a) and (b) will be 
 made at a temperature of seventy (70) degrees Fahr. 
 
 THE GRAVITY CELL 
 USES 
 
 The primary cell in most general use on low voltage closed 
 circuit work is the gravity cell ; it is extensively used in con- 
 nection with track circuits, being adapted to this type of work 
 by its constant voltage characteristics and its freedom from 
 polarization when on closed circuit. Although frequently 
 used on open circuit work, it is not recommended that the 
 cell be used that way, due to the very low efficiency obtained 
 when operating under those conditions. 
 
ELECTRIC INTERLOCKING HANDBOOK 289 
 
 DESCRIPTION 
 
 The elements of this cell are of zinc and copper, and the 
 electrolyte a solution formed by dissolving copper sulphate 
 or "Blue-stone" in pure water. The electrolyte and elements 
 are contained in a glass jar about eight inches in height and 
 six inches in diameter. 
 
 In the type of cell generally employed for signal purposes, 
 the zinc element consists of about four pounds of metallic 
 zinc, cast in the shape of a ring, which is suspended from the 
 upper edge of the glass jar by means of soft wire hangers cast 
 into the element. The copper element, made of thin sheet 
 copper, rests on the bottom of the jar and is covered with 
 copper sulphate crystals. 
 
 The gravity cell has an approximately constant E. M. F. 
 of 1 volt on open circuit and does not polarize through being 
 continually short circuited. The internal resistance varies 
 considerably with the condition of the cell, running from 
 about an ohm when the cell is in good condition to as 
 high as 2 or 3 ohms. When in the best condition the cell 
 has a current capacity on short circuit of about 1 ampere. 
 
 ACTION OF THE CELL 
 
 When first set up, if there are no old cells from which to 
 get zinc sulphate to use in new cells, the battery must be short 
 circuited from twenty-four to forty-eight hours in order to 
 start the action of the cell and to reduce the internal resist- 
 ance. A saturated solution of copper sulphate soon forms 
 around the copper element, and after the cell has been on short 
 circuit for a number of hours, a zinc sulphate is formed around 
 the zinc. Due to the difference of the specific gravities of 
 these two sulphates, the zinc sulphate floats on the copper 
 sulphate, this giving to the cell the name of " gravity cell." 
 
 The action of the cell causes the copper sulphate crystals to 
 dissolve, and when the cell is producing current a deposit of 
 pure copper is made on the copper element. The zinc of the 
 other element is consumed, its surface soon becoming covered 
 with a deposit of grey and brown sludge. This residue consists 
 of part of the impurities of the zinc, which does not dissolve, and 
 if not scraped off at about intervals of two weeks it will coat 
 the zinc to such an extent as to interfere with the action of 
 the cell. As the cell wears out the zinc sulphate increases 
 and the copper sulphate decreases; the copper sulphate 
 crystals in the bottom of the cell are reduced to a paste, and, 
 as mentioned before, the zinc element becomes eaten away 
 by the chemical action. The degree of exhaustion of the cell 
 can be determined by the condition of the zinc element and 
 the amount of copper sulphate crystals remaining in the 
 bottom of the jar. 
 
290 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. ZINC 
 GRAVITY PRIMARY BATTERY 
 R. S. A. plan 1087. Issue October, 1911. 
 
 SPECIFICATION 
 
 1. Zincs shall be made from virgin spelter 
 cast at a low temperature and shall be thor- 
 oughly 'amalgamated with mercury. They 
 shall be uniform in size and weight, free from 
 flaws and mechanical defects and shall have a 
 smooth outer surface. A fracture of the zinc 
 must show the grain firm and close. 
 
 2 The size and shape of zincs shall conform 
 closely to this drawing. 
 
 The brass binding post roust be firmly con- 
 nected both mechanically and electrically to 
 the zinc. The thumb screw must be perfectly 
 threaded and must fit closely 
 
 The manufacturer's name must be cast on 
 the upper flat surface of the zinc in as large 
 letters as the surface will permit and must be 
 raised not less than three-thirty-seconds (&> 
 inch above the surface In addition, the manu- 
 facturer's name or trade-mark must be stamped 
 on some other part in such a position as not to 
 be effaced by the action of the electrolyte or 
 by the process of cleaning. 
 
 3 Weight. The zincs shall weigh four (4) 
 pounds each 
 
 4. The chemical composition of the finished 
 zincs shall be as follows: 
 
 Mercury not less than 2 00% 
 
 Iron not more than 10% 
 
 Lead not more than 50% 
 
 Other impurities not more than 40% 
 Zinc not less than 97 00% 
 
 5. When a shipment of zincs is received, an 
 examination will be made to see that the 
 physical requirements are fulfilled, and >f found 
 satisfactory, one zinc from each fifty (50) or 
 fraction thereof will be taken for chemical 
 analysis. The results of this analysis shall de- 
 termine whether the shipment will be accepted. 
 
 In the event of controversy with the manu- 
 facturer over the chemical composition, one zmc 
 from each 50 or fraction thereof shall be sub- 
 mitted to a disinterested chemist, acceptable to 
 both manufacturer and purchaser, for analysis. 
 If in this analysis the chemical composition of 
 the zincs analyzed is found to be in accordance 
 with this specification, the zincs furnished will 
 be accepted and the cost of the analysis shall be 
 paid by the purchaser. If the chemical com- 
 position is not found to be in accordance with 
 this specification, all expenses in connection 
 with the analysis including the loss on the zincs 
 analyzed shall be borne by the manufacturer. 
 
 The manufacturer shall be advised of all ma- 
 terial rejected as a result of chemical analysis 
 or physical tests, and if at the expiration of two 
 weeks no instructions are received for the return 
 of same, the rejected material shall be returned 
 at the risk of the manufacturer, he paying the 
 freight in both directions in either case. 
 
 The payment for zincs shall be based upon 
 the net weight received. 
 
 6. Zincs must be carefully and securely 
 packed in shavings or sawdust in a stout barrel 
 or box, in lots not to exceed fifty (50) each. 
 The name of the manufacturer and the name 
 of the consignee, together with the destination; 
 number of zincs contained in the package and 
 the purchase order number must be~pfeinly 
 marked on the outside of each package. 
 
 All zincs broken in transit on account of not 
 being properly packed will be returned to the 
 manufacturer, who must promptly replace 
 same free of cost to the purchaser. 
 
 7. Thumb screws for binding poets shall be 
 furnished only when specified 
 
 When furnished, each box or barrel must con- 
 tain at least as many thumb screws as there are 
 lines, the thumb screws being wrapped aepa- 
 rately and tied to one at the zincs just under 
 the cover- 
 
 ZINC 
 
 fcm SUAVITY BATTCRV 
 
 R. S. A. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 291 
 
 R. S. A. COPPERS 
 
 GRAVITY PRIMARY BATTERY 
 
 R. S. A. plan 1088. Issue October, 1911. 
 
 ISSUE: 1911 
 
 SPECIFICATION 
 
 1. MATERIAL, (a) Coppers shall be two-leaf or three-leaf as specified 
 and shall conform to the above drawing. Leaves shall be No. 30 B & S 
 gauge, hard rolled bright copper not less than ninety-eight (98) per cent, 
 pure. 
 
 (6) Lead wire shall be No. 14 B & S gauge, solid soft drawn copper, insu- 
 lated throughout the entire length, except one (1) inch at each end. The 
 insulation shall consist of a three-sixty-fourths (%4> inch wall of rubber, 
 shall adhere tightly to the wire and shall be of a character suitable to with- 
 stand the action of the battery solution. Insulation on ends of wire to be 
 trimmed either tapered or square, and in this operation the wire must not 
 be scored. 
 
 (c) End of wire attached to copper must be thoroughly cleaned and tightly 
 riveted as shown with a rivet having a three-eighths (%) inch head and a 
 washer three-eighths (%) inch in outer diameter. Both rivets and washer 
 shall be copper not less than ninety-eight (98) per cent. pure. 
 
 2. PACKINO AND MARKING. Copper shall be carefully and securely 
 packed in lots of one-hundred (100) each, or fifty (50) if so specified, and 
 the purchase order number, contents of package, name of manufacturer 
 and name and address of consignee shall be plainly marked on the outside 
 of each package. 
 
 3. INSPECTION AND ACCEPTANCE. One copper taken at random from 
 each fifty (50) or fraction thereof shall be examined and tested. The results 
 of this examination shall determine whether the lots so represented will be 
 accepted. If the samples are found to meet this specification, the material 
 will be accepted. If any of the samples fail to meet this specification, the 
 
 he paying the freight in both directions. 
 
292 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. BATTERY CHUTES 
 R. S. A. plan 1230. Issue December, 1912. 
 
 12283 i i 12292 
 
 12283- 
 
 c 
 
 4 
 
 ^ 
 
 j|i 
 
 ^^ 
 
 
 5'ji 
 
 
 _J[ 
 
 t 
 
 = 
 
 zr=. 
 
 : 
 -i 
 
 I 
 
 
 -1 
 
 In 
 
 ffl 
 
 
 
 
 
 
 
 HEAD BOLT & 
 NUT (12 309) 
 
 
 
 
 
 
 \2309 
 
 
 
 
 H 
 
 
 
 
 
 
 -r-12291 
 
 
 
 
 
 l"~ 
 i 
 
 _._.J 
 
 -12284 
 -12285 
 
 . 
 
 i 
 
 .,_> 
 
 NOTE 
 
 WHEN ORDERING 
 APPARATUS OR 
 PARTS SHOWN ON 
 THIS PlAN GIVE 
 NUMBER AND 
 NAME APPEARING 
 
 , 
 
 , 
 
 -12294 
 
 
 'LL 
 
 
 
 u 
 
 
 
 
 -12286 
 
 
 
 
 
 
 -12298 
 
 V 
 
 . 
 
 3 
 
 ASSEMBLY OF SINGLE CHUTES ASSEMBLY OF DOUBLE CHUTES 
 
 12301 = 6 FT. CHUTE 12303 = 6 FT. CHUTE 
 
 12302 = 6 FT. [WITH 12278] 12304=6 FT. [WITH i227io - 12293] 
 
 12305 = 7 FT. 12307 = 7 FT. 
 12306 = 7 FT- [WITH 12278] 12308=7 FT. [WITH ,227iO - 12295] 
 
 12309 -8 FT. 123011=8 FT. 
 123010=8 FT. [WITH i2?78J 123012^8 FT. [WITH I227i0 - 12297] 
 
 123013 = 9 FT. ' 123015 = 9 FT. 
 
 123014=9 FT. [WITH i2278] 123016 = 9 FT, [WITH i227ifl - 1?299] 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 293 
 
 CARE OF THE CELL 
 
 In making renewals, the jars should be well washed, being 
 scoured until they are transparent. The elements should be 
 cleaned and replaced in the jar with clean cop- 
 per sulphate crystals; the cell should then be 
 filled to a point just below the bottom of the 
 zinc element with water and then within one- 
 half inch of the top of the jar with clear zinc 
 sulphate taken from the top of the old cell 
 this in order to start a strong chemical action 
 and have the cell available for immediate service. 
 
 The cell should be inspected every two weeks 
 and the residue which has formed on the zinc 
 element be scraped off. At the same time the 
 maintainer should check the specific gravity of 
 the electrolyte. The best operation of the cell 
 will be secured by keeping the density of the solu- 
 tion at about twenty degrees Baume (see page 
 384), and under no condition should it exceed 
 thirty degrees; the density can be lowered by 
 dipping out some of the solution and refilling the 
 cell with water. 
 
 The bottom of the zinc element should be main- 
 tained about two and one-half inches above the 
 level of the copper sulphate crystals. 
 
 The ampere output of the cell falls off consid- 
 erably with a decrease in temperature. Under no 
 conditions should the cell be exposed to a tem- 
 perature below thirty-two degrees Fahr., as the 
 solution congeals at slightly below that point and 
 freezes with a further reduction in temperature, 
 this interrupting the action of the cell and in a 
 
 FIG. 250. SEC- great many cases breaking the jar. When installed 
 TION OP SIN- outside of the interlocking station the cells are 
 GLE BATTERY housed in battery chutes or wells set in the 
 CHUTE WITH grO und to place them beyond the reach of frost, 
 
 the proper depth of the housing depending on 
 
 climatic conditions. 
 
 THE DRY CELL 
 
 USES 
 
 The dry cell is most commonly used in connection with 
 circuits which are only closed momentarily, or for a few seconds 
 at infrequent intervals. It is employed for such purposes as 
 operating annunciators, buzzers, etc., and sometimes in the 
 ignition circuit of gasoline engines. 
 
294 GENERAL RAILWAY SIGNAL COMPANY 
 
 DESCRIPTION 
 
 The cell is contained in a zinc shell which forms one ele- 
 ment; the other element consists of a stick of carbon set in 
 the center of the cell. The zinc shell is usually lined with 
 several thicknesses of blotting paper and the remaining space 
 around the carbon element filled with a mixture of carbon, 
 manganese dioxide, sawdust, or other absorbent substance. 
 This mixture is then saturated with a solution of sal ammoniac 
 (muriate of ammonia) and water, and the top of the cell sealed 
 with wax or pitch. To insulate the zinc shell from adjacent 
 cells, metal pipes, etc., a cylindrical pasteboard cover is fur- 
 nished covering the sides and bottom of the cell. 
 
 The cell has an approximate E. M. F. of 1.5 volts which falls 
 off after the cell has been in service for some time. The 
 internal resistance is about .075 ohm. The cell polarizes very 
 quickly when on short circuit, giving less and less current 
 as it becomes more polarized, until it finally refuses to deliver 
 current at all ; the cell takes some time to recover when fully 
 polarized. 
 
 Exhaustion of the cell, except when polarized, is usually 
 due to the sal ammoniac having been entirely consumed. 
 The zinc container is gradually consumed by the action of the 
 cell, this resulting in "puncturing," or the eating through in 
 spots, of the zinc. 
 
 CARE OF THE CELL 
 
 The cell practically requires no care other than keeping it 
 in a dry place which has an even temperature of about 
 seventy degrees Fahr. Temperatures below this will limit the 
 amount of current which can be drawn from the cell, while a 
 greater temperature materially reduces the cell's life through 
 drying up the sal ammoniac. 
 
 The cell is in reality a wet cell, sealed to prevent the paste 
 from drying out. If the cell does actually become dry it will 
 not produce any current, but if the elements have not been 
 worn out this can be overcome by boring a hole in the top of 
 the cell and soaking it in water for two or three days. 
 
 Care should be taken to avoid handling the cells roughly, as 
 the contents of the cell are apt to become broken away from 
 the carbon electrode, this resulting in an increase of the internal 
 resistance of the cell and a consequent reduction in the current 
 output. 
 
 EDITOR'S NOTE 
 
 Articles on primary cells, pages 285, 288 and 293, based on 
 data furnished by National Carbon Co, 
 
SECTION XIII 
 
 WIRE, TRUNKING AND CONDUIT 
 
 COVERING INSTALLATION PRACTICE, 
 TABLES OF PHYSICAL PROPERTIES OF 
 WIRE, REQUIRED SIZES OF CONTROL 
 AND COMMON WIRES, TRUNKING CON- 
 STRUCTION, AND THE CARRYING CA- 
 PACITIES OF TRUNKING AND CONDUIT 
 
WIRE AND WIRING 
 
 EXTRACTS FROM R. S. A SPECIFICATIONS FOR 
 
 ELECTRIC INTERLOCKING (1910) 
 521. SIZE 
 
 (a) Wires shall be of sufficient size to permit operation 
 of switch and signal mechanism in accordance with pre- 
 vious specifications. 
 
 (6) Rubber-covered wire smaller than number fourteen 
 (14) B. &. S. gauge shall not be used. 
 
 (c) Hard-drawn copper line wire shall not be smaller 
 than number ten (10) B. & S. gauge. 
 
 (d) No common return wire shall be less than number 
 twelve (12) B. & S. gauge. 
 
 (e) In submarine cable work spare wires up to twenty- 
 five (25) per cent, of the number in use shall be provided 
 as specified. When spare wires are required in other than 
 cable work the number and size shall be specified. 
 
 ( / ) Numbers and sizes of track circuit connections 
 shall be as follows : 
 
 No. of B. & S. 
 
 conductors gauge 
 
 1. Track batteries to rail one (1) nine (9) or. 
 
 2. Relays to rail one (1) nine (9) or. 
 
 3. Fouling shunt connections . . .two (2) nine (9) or. . .(.) 
 
 4. Switch circuit controller 
 
 connections two (2) nine (9) or ...(.) 
 
 5. Wire from trunking to 
 
 track batteries in chutes, 
 
 stranded twelve (12) or ...(.) 
 
 (g) Wires connected to track shall be rubber-covered 
 soft-drawn copper. 
 
 525. WIRING 
 
 (a) Wires in trunking, chases or conduits shall be laid 
 loosely without stretching or crowding. 
 
 (6) Not more than two (2) wires shall be connected to 
 one (1) binding post or terminal screw. 
 
 (c) Unless otherwise specified, all wires shall be run as 
 separate conductors. 
 
 526. COMMON RETURN 
 
 (a) Reductions in size of common wire and connec- 
 tions to pole lines shall be made in junction boxes. 
 
 (6) Connections between branches and main common 
 wires shall be made in junction boxes. 
 
 NOTE. Wire sizes given in (/) taken from R. S. A. Automatic Block 
 Signal Specifications (521-/ dated 1913). 
 
298 GENERAL RAILWAY SIGNAL COMPANY 
 
 (c) Unless otherwise specified, common return wires 
 shall be continuous without joints or breaks from inter- 
 locking machine to the limits of the interlocking plant. 
 
 527. JOINTS IN WIRE 
 
 (a) Wires shall, as far as practicable, be continuous 
 without joints or breaks between interlocking machine 
 and the unit operated ; joints when made shall be in junc- 
 tion boxes, and only made on permission from the Engi- 
 neer. 
 
 (6) In making joints, braid shall be pulled back one (1) 
 inch from end of rubber on each side of splice, and rubber 
 cut with knife held at an angle of approximately thirty 
 (30) degrees with axis of wire, as one would sharpen a 
 pencil. 
 
 (c) After removing rubber, wire shall be thoroughly 
 cleaned, care being taken to prevent injury from small 
 cuts or nicks. 
 
 (d) Wire, after being cleaned, shall be twisted together 
 in the form of a regular line wire splice, turns being spaced 
 approximately one-sixty-fourth (Ve4) inch. 
 
 (e) Joints shall then be soldered by pouring on them, or 
 dipping them into, melted solder, a non-corrosive rosin 
 flux being used. After soldering, joints shall be painted 
 
 with insulating paint or with 
 
 compound. 
 
 (7) Joints shall then be covered with two (2) layers of 
 
 insulating tape between ends of braid, which 
 
 tape shall be heated sufficiently to form a tight covering, 
 but not enough to injure the quality of the material. Coat- 
 ing of insulating paint or com- 
 pound shall be put on over insulating tape and two (2) 
 
 layers of adhesive or friction tape shall be 
 
 applied, after which the outside of the joint is to be painted 
 with insulating paint. 
 
 528. FUSES 
 Material. 
 
 (a) Fuses shall be of the enclosed type. 
 Field work. 
 
 (6) The necessary fuses to properly protect all appa- 
 ratus and circuits shall be installed. 
 
 (c) Fuses outside of buildings shall be enclosed in 
 weatherproof boxes. 
 
 (d) In the lighting circuits, a fuse shall be provided in 
 the circuit to each signal lamp; in the circuit to each 
 set of lamps on a mast; in each branch circuit leaving 
 the mains, and in each set of mains leaving the switch- 
 board. 
 
 (e) Double pole fuse cut-out shall be provided for each 
 circuit on the power board. 
 
ELECTRIC INTERLOCKING HANDBOOK 299 
 
 (/) An additional double pole fuse cut-out shall be 
 placed in storage battery leads as near as possible to the 
 battery terminals. 
 
 530. TAGS. 
 Material. 
 
 (a) Tags shall be made of vulcanized sheet fibre, not 
 less than one-sixteenth (He) inch thick, firmly attached to 
 the wire by the best quality yacht marline one-sixteenth 
 (Vie) inch in diameter. 
 
 (6) The tag shall have a stamped imprint to show the 
 function of the wire. 
 Field work. 
 
 (c) Wires shall be tagged at all junction boxes, switches, 
 signals, relay boxes, arrester boxes, and at all line wire 
 connections, unless otherwise specified. 
 
 FLUXES FOR SOLDERING AND WELDING 
 
 Iron, Borax. 
 
 Tinned Iron, .... Resin. 
 Copper and brass, . . Sal ammoniac. 
 
 Zinc, Chloride of zinc. 
 
 Lead, Tallow or resin. 
 
 Lead and tin pipes, . . Resin and sweet oil. 
 
 Steel, Pulverize 1 part sal ammoniac, 10 
 
 parts borax, and fuse until clear. 
 
 When solidified, pulverize to powder. 
 
 INSTRUCTIONS FOR SPLICING, SOLDERING, AND 
 TAPING JOINTS IN RUBBER-COVERED WIRE 
 
 STRIPPING THE INSULATION 
 
 When stripping the insulation, the knife blade should be 
 held at such an angle as one would use in sharpening a pencil ; 
 do not hold the blade at right angles to the wire, as the wire is 
 apt to be nicked if this is done. 
 
 SPLICING STRANDED WIRE TO STRANDED WIRE 
 
 Remove the insulation carefully from the end of each 
 wire for three to four inches, according to the size of the 
 wire. Remove the braid about one inch further back from 
 the bare portion of the wire, being careful not to cut the 
 rubber. If the strands become untwisted, twist together and 
 clean thoroughly of rubber, leaving the wire bright. 
 
300 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Starting as shown in Fig. 251, twist the wires together in the 
 regular manner of making a line wire joint; cut off surplus 
 wire, as shown in Fig. 252, and solder and tape as described 
 under "Soldering" and "Taping." See Figs. 253 and 254 
 for appearance of soldered and finished joints. 
 
 FIG. 251 
 
 FIG. 252 
 
 FIG. 253 
 
 %;^ 
 
 FIG. 254 
 SPLICING STRANDED WIRE TO STRANDED WIRE 
 
 SPLICING STRANDED WIRE TO SOLID WIRE 
 
 Remove the insulation from the solid wire for about one and 
 one-half inches and from the stranded wire for three to four 
 inches, according to the size of the wire. Remove the braid 
 for about one inch back from the bare portion of the wire. 
 being careful not to cut the rubber. 
 
 FIG. 255 
 
 c= 
 
 FIG. 256 
 
 3r$2S^i 
 
 
 
 FIG. 257 
 
 jxwwxr-7-r-i-^r 
 
 wx**ywsd / / ^ ^ 
 
 '\tV<Ay>WWVK)WW^ 
 -axxwxAMrt.vxxxxx^ 
 
 FIG. 258 
 SPLICING STRANDED WIRE TO SOLID WIRE 
 
ELECTRIC INTERLOCKING HANDBOOK 301 
 
 Clean both stranded and solid wires, leaving them bright. 
 If the strands of the stranded wire become untwisted, twist 
 them together and starting as shown in Fig. 255, twist the 
 stranded wire around the solid wire, leaving about the thick- 
 ness of the stranded wire between the turns for about two 
 turns, and then wind close; cut off the solid wire, leaving 
 enough to turn an eye around the stranded wire as shown in 
 Fig. 256. Solder and tape as described under " Soldering " 
 and " Taping." 
 
 FIG. 259 
 
 
 FIG. 260 
 
 FIG. 262 
 SPLICING SOLID WIRE TO SOLID WIRE 
 
 SPLICING SOLID WIRE TO SOLID WIRE 
 
 The insulation should be removed from four to six inches 
 from the end of each wire. Remove the braid for about one 
 inch from the ends of the insulation. The bare wire should 
 be thoroughly cleaned of all rubber. Lay the two wires 
 together so that the distance between the insulations will be 
 about one and one-half or one and three-fourths inches, 
 as shown in Fig. 259. Hold the middle of the joint with 
 the pliers and twist the end of one wire around the other, 
 leaving about one sixty-fourth inch between turns for solder 
 to run in, as shown in Fig. 260. This winding should stop 
 when the insulation is reached and the surplus wire then be 
 cut off. The other end should be wound in this same man- 
 ner and the middle part twisted for three or four turns. 
 Solder and tape the joint as described under "Soldering" and 
 "Taping." 
 
302 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 263 
 
 FIG. 264 
 
 
 FIG. 265 
 
 V V \ 
 
 =A =^ J ^ 
 
 FIG. 266 
 MAKING T JOINTS IN SOLID WIRE 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 MAKING T JOINTS IN STRANDED OR SOLID WIRES 
 
 Remove the insulation from the continuous wire where the 
 joint is to be made for about one and one-fourth inches and 
 the braid for about one inch beyond the ends of the insula- 
 tion. Remove the insulation from the end of the tap wire 
 in the same manner as described for joints in solid wire. Lay 
 the end of the tap wire across the bare part of the continuous 
 wire as shown in Fig. 263 and wrap around the continuous 
 wire as shown in Fig. 264, stopping when the insulation is 
 reached. Cut off the surplus wire and solder and tape as 
 described under "Soldering" and "Taping." 
 
 
 FIG. 267. PARALLEL, JOINTS 
 
 PARALLEL JOINTS 
 
 When two or more joints come side by side, as sometimes 
 happens in parallel wires, one joint should be lapped beyond 
 the other so as to leave at least three-fourths inch of the 
 original insulation between the joints, as shown in Fig. 267. 
 
 SOLDERING 
 
 In soldering it is recommended that an approved soldering 
 compound in stick form, such as Allen's Soldering Compound, 
 be used. Joints should be soldered by pouring melted solder 
 over the joint or, if impractical to do this, the work should be 
 done with a well-tinned soldering copper having sufficient 
 heat to thoroughly heat the entire joint. Never use an open 
 flame for soldering joints. 
 
 FIG. 268 
 
 FIG. 269 
 METHOD OP TAPING 
 
 TAPING 
 
 All joints whether for inside or outside work must be taped 
 with Okonite tape (or its equivalent) in the following manner: 
 The tape should first be stretched to insure its laying tight to 
 the wire. Start the tape close up to the rubber insulation 
 (see Fig. 268) and wind with a half lap over the joint and rubber 
 
304 GENERAL RAILWAY SIGNAL COMPANY 
 
 insulation to, but not over, the braid at the end ; thence back 
 over joint and rubber insulation to, but not over, the braid on 
 the other end, and then back to where taping was started 
 (see Fig. 269). Warm the joint sufficiently to soften the tape 
 slightly, squeezing the tape down with the hand to make it 
 adhere closely to the rubber insulation and to itself. 
 
 Black friction tape of good quality should be applied over 
 the rubber tape, using three-eighths inch tape for No. 16 
 wire or smaller, five-eighths inch tape for No. 14 to No. 10 
 wire inclusive, and three-fourths inch tape for wires larger 
 than No. 10. Start the tape near the middle of the joint and 
 using a half lap, wind about one-half inch beyond the braid 
 at one end; then back to one-half inch beyond the braid 
 at the other end, thence back and finish near the middle of the 
 joint. In order to make a neat, strong joint, it is necessary to 
 draw the tape tight during the whole operation. 
 
 See Figs. 254, 258, 262, and 266 for appearance of finished 
 joints. Care should be taken to keep the nands free from oils 
 or grease, as these will injure both the rubber tape and the 
 adhesive qualities of the friction tape. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 305 
 
 COMPARISON OF BROWN & SHARPE AND BIRMINGHAM 
 WIRE GAUGES 
 
 BROWN & SHARPE GAUGE 
 
 BIRMINGHAM WIRE GAUGE 
 
 Gauge 
 Num- 
 ber 
 
 Diam. 
 in 
 Inches 
 
 Area 
 
 Gauge 
 Num- 
 ber 
 
 Diam. 
 in 
 Inches 
 
 Area 
 
 Circular 
 Mils 
 
 Square 
 Inches 
 
 Circular 
 Mils. 
 
 Square 
 Inches 
 
 0000 
 
 .4600 
 
 211600 
 
 .166190 
 
 0000 
 
 .4540 
 
 206100 
 
 . 161883 
 
 000 
 
 .4096 
 
 167800 
 
 .131790 
 
 000 
 
 .4250 
 
 180600 
 
 .141863 
 
 00 
 
 .3648 
 
 133100 
 
 . 104518 
 
 00 
 
 .3800 
 
 144400 
 
 .113411 
 
 
 
 .3249 
 
 105500 
 
 .082887 
 
 
 
 .3400 
 
 115600 
 
 .090792 
 
 1 
 
 .2893 
 
 83690 
 
 .065732 
 
 1 
 
 .3000 
 
 90000 
 
 .070686 
 
 2 
 
 .2576 
 
 66370 
 
 .052128 
 
 2 
 
 .2840 
 
 80660 
 
 .063347 
 
 3 
 
 .2294 
 
 52630 
 
 .041339 
 
 3 
 
 .2590 
 
 67080 
 
 .052685 
 
 4 
 
 .2043 
 
 41740 
 
 .032784 
 
 4 
 
 .2380 
 
 56640 
 
 .044488 
 
 5 
 
 .1819 
 
 33100 
 
 .025999 
 
 5 
 
 .2200 
 
 48400 
 
 .038013 
 
 6 
 
 .1620 
 
 26250 
 
 .020618 
 
 6 
 
 .2030 
 
 41210 
 
 .032365 
 
 7 
 
 .1443 
 
 20820 
 
 .01635J 
 
 7 
 
 .1800 
 
 32400 
 
 .025447 
 
 8 
 
 .1285 
 
 16510 
 
 .012967 
 
 8 
 
 .1650 
 
 27230 
 
 .021382 
 
 9 
 
 .1144 
 
 13090 
 
 .010283 
 
 9 
 
 .1480 
 
 21900 
 
 .017203 
 
 10 
 
 .1019 
 
 10380 
 
 .008155 
 
 10 
 
 .1340 
 
 17960 
 
 .014103 
 
 11 
 
 .0907 
 
 8234 
 
 .006467 
 
 11 
 
 .1200 
 
 14400 
 
 .011310 
 
 12 
 
 .0808 
 
 6530 
 
 .005129 
 
 12 
 
 .1090 
 
 11880 
 
 .009331 
 
 13 
 
 .0720 
 
 5178 
 
 .004067 
 
 13 
 
 .0950 
 
 9025 
 
 .007088 
 
 14 
 
 .0641 
 
 4107 
 
 .003225 
 
 14 
 
 .0830 
 
 6889 
 
 .005411 
 
 15 
 
 .0571 
 
 3257 
 
 .002558 
 
 15 
 
 .0720 
 
 5184 
 
 .004072 
 
 16 
 
 .0508 
 
 2583 
 
 .002029 
 
 16 
 
 .0650 
 
 4225 
 
 .003318 
 
 NOTE. 1 Mil.^.OOl inch. 1 Circular Mil. = Area of 1 Mil. diameter. 
 
306 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 SOFT-DRAWN COPPER WIRE 
 
 
 
 RESISTANCE IN 
 
 WEIGHT IN POUNDS 
 
 Number 
 
 Diameter 
 
 OHMS AT 68 F 
 
 Bare Wire 
 
 R. S. A. 
 
 Gauge 
 
 in Inches 
 
 Per 
 1000 Ft. 
 
 Per 
 
 Mile 
 
 
 
 Per 
 
 1000 ft. 
 
 Per 
 Mile 
 
 Per 
 1000 ft. 
 
 Per 
 Mile 
 
 
 
 .325 
 
 .10 
 
 .52 
 
 320 
 
 1687 
 
 525 
 
 2772 
 
 1 
 
 .289 
 
 .12 
 
 .65 
 
 253 
 
 1337 
 
 423 
 
 2233 
 
 2 
 
 .258 
 
 .16 
 
 .82 
 
 201 
 
 1062 
 
 358 
 
 1890 
 
 4 
 
 .204 
 
 .25 
 
 1.31 
 
 126 
 
 667 
 
 224 
 
 1183 
 
 6 
 
 .162 
 
 .39 
 
 2.08 
 
 79 
 
 419 
 
 158 
 
 834 
 
 8 
 
 .128 
 
 .63 
 
 3.31 
 
 50 
 
 264 
 
 116 
 
 613 
 
 9 
 
 .114 
 
 .79 
 
 4.18 
 
 40 
 
 209 
 
 85 
 
 449 
 
 10 
 
 .102 
 
 1.00 
 
 5.27 
 
 31 
 
 166 
 
 80 
 
 422 
 
 12 
 
 .081 
 
 1.59 
 
 8.37 
 
 20 
 
 104 
 
 61 
 
 322 
 
 14 
 
 .064 
 
 2.52 
 
 13.31 
 
 12 
 
 66 
 
 50 
 
 264 
 
 16 
 
 .051 
 
 4.01 
 
 21.17 
 
 8 
 
 41 
 
 32 
 
 169 
 
 GALVANIZED IRON AND STEEL WIRE 
 
 fcPQ 
 
 OS 
 
 BREAKING 
 WEIGHTS 
 POUNDS 
 
 RESISTANCE PER 
 MILE IN OHMS. 
 AT 68 F. 
 
 WEIGHT IN POUNDS 
 
 Bare Wire 
 
 Double Braid 
 Weather- 
 proof 
 
 Triple Braid 
 Weather- 
 proof 
 
 Iron 
 
 Steel 
 
 E.B.B 
 
 B.B. 
 
 Steel 
 
 Per 
 1000 
 ft. 
 
 Per 
 
 Mile 
 
 Per 
 
 1000 
 
 ft. 
 
 Per 
 
 Mile 
 
 Per 
 1000 
 ft. 
 
 Per 
 Mile 
 
 
 
 .340 
 
 4821 
 
 9079 
 
 2.93 
 
 3.42 
 
 4.05 
 
 304 
 
 1607 
 
 
 
 
 
 1 
 
 .300 
 
 3753 
 
 7068 
 
 3.76 
 
 4.4 
 
 5.2 
 
 237 
 
 1251 
 
 
 
 
 
 2 
 
 .284 
 
 3363 
 
 6335 
 
 4.19 
 
 4.91 
 
 5.8 
 
 212 
 
 1121 
 
 
 
 
 
 4 
 
 .238 
 
 2361 
 
 4449 
 
 5.97 
 
 6.99 
 
 8.26 
 
 149 
 
 787 
 
 163 
 
 860 
 
 178 
 
 940 
 
 6 
 
 .203 
 
 1719 
 
 3237 
 
 8.21 
 
 9.6 
 
 11.35 
 
 109 
 
 573 
 
 126 
 
 665 
 
 140 
 
 740 
 
 8 
 
 .165 
 
 1134 
 
 2138 
 
 12.42 
 
 14.53 
 
 17.18 
 
 72 
 
 378 
 
 89 
 
 470 
 
 100 
 
 525 
 
 9 
 
 .148 
 
 915 
 
 1720 
 
 15.44 
 
 18.06 
 
 21.35 
 
 58 
 
 305 
 
 76 
 
 400 
 
 85 
 
 450 
 
 10 
 
 .134 
 
 750 
 
 1410 
 
 18.83 
 
 22.04 
 
 26.04 
 
 47 
 
 250 
 
 66 
 
 350 
 
 76 
 
 400 
 
 12 
 14 
 
 .109 
 .083 
 
 495 
 
 288 
 
 933 
 541 
 
 28.4633.3 
 49.0857.44 
 
 39.36 
 
 67.88 
 
 31 
 
 18 
 
 165 
 96 
 
 43 
 28 
 
 225 
 145 
 
 49 
 33 
 
 260 
 175 
 
 16 
 
 .065 
 
 177 
 
 332 
 
 80.03J93.66 
 
 110.7 
 
 11 
 
 59 
 
 
 
 ... 
 
 ... 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 307 
 
 HARD-DRAWN COPPER WIRE 
 
 CO 
 
 
 
 RESISTANCE 
 
 WEIGHT IN POUNDS 
 
 y 
 
 PQ w> 
 *- 
 
 Diam- 
 eter 
 Bare 
 
 Break- 
 ing 
 Weight 
 
 IN OHMS AT 
 68 F. 
 
 Bare Wire 
 
 Double Braid 
 Weatherproof 
 
 Triple Braid 
 Weath'rprool 
 
 a 
 { 
 
 Wire 
 in In. 
 
 in 
 Pounds 
 
 Per 
 1000 
 Ft. 
 
 Per 
 Mile 
 
 Per 
 1000 
 Ft. 
 
 Per 
 
 Mile 
 
 Per 
 1000 
 Ft. 
 
 Per 
 
 Mile 
 
 Per 
 1000 
 Ft. 
 
 Per 
 
 Mile 
 
 
 
 .325 
 
 4973 
 
 .10 
 
 .53 
 
 320 
 
 1687 
 
 377 
 
 1989 
 
 407 
 
 2150 
 
 i 
 
 .289 
 
 3943 
 
 .13 
 
 .67 
 
 253 
 
 1337 
 
 294 
 
 1553 
 
 316 
 
 1670 
 
 2 
 
 .258 
 
 3127 
 
 .16 
 
 .85 
 
 201 
 
 1062 
 
 239 
 
 1264 
 
 260 
 
 1370 
 
 4 
 
 .204 
 
 1967 
 
 .26 
 
 1.35 
 
 126 
 
 667 
 
 151 
 
 795 
 
 164 
 
 865 
 
 6 
 
 .162 
 
 1237 
 
 .41 
 
 2.14 
 
 79 
 
 419 
 
 100 
 
 529 
 
 112 
 
 590 
 
 8 
 
 .128 
 
 778 
 
 .64 
 
 3.39 
 
 50 
 
 264 
 
 66 
 
 349 
 
 75 
 
 395 
 
 9 
 
 .114 
 
 617 
 
 .81 
 
 4.29 
 
 40 
 
 209 
 
 54 
 
 283 
 
 62 
 
 325 
 
 10 
 
 .102 
 
 489 
 
 1.02 
 
 5.41 
 
 31 
 
 166 
 
 46 
 
 241 
 
 53 
 
 280 
 
 12 
 
 .081 
 
 307 
 
 1.62 
 
 8.60 
 
 20 
 
 104 
 
 30 
 
 158 
 
 35 
 
 185 
 
 14 
 
 .064 
 
 193 
 
 2.20 
 
 11.59 
 
 12 
 
 66 
 
 20 
 
 107 
 
 25 
 
 130 
 
 16 
 
 .051 
 
 133 
 
 4.12 
 
 21.74 
 
 8 
 
 41 
 
 16 
 
 83 
 
 20 
 
 105 
 
 COPPER-CLAD WIRE GRADE "A" 
 BBIGHT, HARD DRAWN 
 
 00 
 
 
 
 RESISTANCE 
 
 WEIGHT IN POUNDS 
 
 8 
 
 n'S) 
 
 u 3 
 
 Diam- 
 eter 
 Bare 
 
 Break- 
 ing 
 Weight 
 
 IN OHMS AT 
 60 F. 
 
 Bare Wire 
 
 Double Braid 
 Weatherproof 
 
 Triple Braid 
 Weath'rproof 
 
 o 
 
 
 
 5 
 
 Wire 
 in In. 
 
 in 
 Pounds 
 
 Per 
 1000 
 Ft. 
 
 Per 
 
 Mile 
 
 Per 
 
 1000 
 Ft. 
 
 Per 
 Mile 
 
 Per 
 1000 
 Ft. 
 
 Per 
 Mile 
 
 Per 
 1000 
 Ft. 
 
 Per 
 
 Mile 
 
 
 
 .325 
 
 5472 
 
 .32 
 
 1.70 
 
 293 
 
 1546 
 
 350 
 
 1850 
 
 381 
 
 2011 
 
 i 
 
 .289 
 
 4798 
 
 .41 
 
 2.14 
 
 232 
 
 1226 
 
 273 
 
 1443 
 
 295 
 
 1560 
 
 2 
 
 .258 
 
 3804 
 
 .51 
 
 2.70 
 
 184 
 
 972 
 
 223 
 
 1177 
 
 243 
 
 1283 
 
 4 
 
 .204 
 
 2721 
 
 .81 
 
 4.29 
 
 116 
 
 611 
 
 140 
 
 740 
 
 153 
 
 810 
 
 6 
 
 .162 
 
 1797 
 
 1.29 
 
 6.82 
 
 73 
 
 384 
 
 94 
 
 494 
 
 105 
 
 555 
 
 8 
 
 .128 
 
 1187 
 
 2.05 
 
 10.84 
 
 46 
 
 242 
 
 62 
 
 327 
 
 71 
 
 373 
 
 9 
 
 .114 
 
 984 
 
 2.59 
 
 13.68 
 
 36 
 
 192 
 
 51 
 
 266 
 
 58 
 
 308 
 
 10 
 
 .102 
 
 780 
 
 3.26 
 
 17.24 
 
 29 
 
 152 
 
 43 
 
 227 
 
 51 
 
 266 
 
 12 
 
 .081 
 
 512 
 
 5.20 
 
 27.43 
 
 18 
 
 96 
 
 28 
 
 149 
 
 33 
 
 176 
 
 14 
 
 .064 
 
 334 
 
 8.25 
 
 43.60 
 
 11 
 
 60 
 
 19 
 
 101 
 
 24 
 
 127 
 
 16 
 
 .051 
 
 216 
 
 13.14 
 
 69.40 
 
 7 
 
 38 
 
 15 
 
 80 
 
 19 
 
 102 
 
 NOTE. -Average conductivity, 30 per cent, 
 per cent. 
 
 Minimum conductivity, 27 
 
308 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 1 1 
 
 b- iO <*< C^J 
 -< rH <N <N 
 
 iO iO 
 
 O CD r-t 
 
 ^O iO 
 
 t>. t^ 
 
 C^C^ 
 
 O O 
 
 (N CO CO 
 
 O CO !> 
 
 !> 
 
 (NC^IOOOOCO TH r-t rH <N 
 
 o *o o o o o 
 
 ^ Ci t^ *O Cl *-* 
 
 <N CM CN 
 
 i-l <N <M CO CO CO CO 
 
 O O 00 CO O 
 CO CO ^ 
 
 !i 
 
 & . . ^2 
 
 g . * - 
 03 Q 
 
 . <! 
 
 < .-< -W . - 
 
 WWWPP03 03 03 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 309 
 
 COMMON RETURN WIRE 
 
 DETERMINATION OF THE REQUIRED SIZE WIRE FOR A GIVEN 
 LENGTH OF COMMON 
 
 Max. 
 Amps. 
 
 NUMBER OF COMMON WIRE, B. & S. GAUGE 
 
 Max. 
 Amps. 
 
 
 I I 
 
 
 
 
 
 
 
 
 In 
 
 14 
 
 12 
 
 10 
 
 9 
 
 8 
 
 6 
 
 4 
 
 2 
 
 1 
 
 
 
 00 
 
 000 
 
 in 
 
 Com- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Com- 
 
 mon 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 Ft. 
 
 mon 
 
 4.5 
 
 503 
 
 802 
 
 1275 
 
 1600 
 
 2025 
 
 3220 
 
 5120 
 
 8140 
 
 10275 
 
 129.50 
 
 16300 
 
 20550 
 
 4.5 
 
 6 
 
 378 
 
 603 
 
 956 
 
 1205 
 
 1521 
 
 2420 
 
 3850 
 
 6115 
 
 7710 
 
 974012250 
 
 15450 
 
 6 
 
 7 
 
 324 
 
 517 
 
 820 
 
 1032 
 
 1305 
 
 2075 
 
 3300 
 
 5245 
 
 6620 
 
 835010050 
 
 13250 
 
 7 
 
 9 
 
 254 
 
 404 
 
 640 
 
 807 
 
 1020 
 
 1620 
 
 2560 
 
 4100 
 
 5160 
 
 6525 
 
 8210 
 
 10350 
 
 9 
 
 10 
 
 227 
 
 361 
 
 575 
 
 724 
 
 913 
 
 1451 
 
 2310 
 
 3670 
 
 4630 
 
 5840 
 
 7350 
 
 9275 
 
 10 
 
 11.5 
 
 197 
 
 314 
 
 503 
 
 628 
 
 792 
 
 1260 
 
 2010 
 
 3190 
 
 4125 
 
 5075 
 
 6390 
 
 8500 
 
 11.5 
 
 13 
 
 174 
 
 278 
 
 441 
 
 555 
 
 701 
 
 1115 
 
 1772 
 
 2820 
 
 3560 
 
 4490 
 
 5650 
 
 7125 
 
 13 
 
 14 
 
 162 
 
 258 
 
 410 
 
 517 
 
 654 
 
 1040 
 
 1650 
 
 2620 
 
 3300 
 
 4170 
 
 5250 
 
 6625 
 
 14 
 
 16 
 
 142 
 
 226 
 
 359 
 
 453 
 
 570 
 
 907 
 
 1445 
 
 2295 
 
 2890 
 
 3650 
 
 4600 
 
 5800 
 
 16 
 
 18 
 
 126 
 
 202 
 
 318 
 
 410 
 
 507 
 
 806 
 
 1280 
 
 2040 
 
 2570 
 
 3240 
 
 4085 
 
 5150 
 
 18 
 
 20 
 
 113 
 
 181 
 
 287 
 
 362 
 
 456 
 
 726 
 
 1155 
 
 1835 
 
 2312 
 
 2920 
 
 3680 
 
 4630 
 
 20 
 
 22 
 
 103 
 
 164 
 
 261 
 
 329 
 
 415 
 
 660 
 
 1150 
 
 1670 
 
 2120 
 
 2660 
 
 3345 
 
 4215 
 
 22 
 
 24 
 
 94 
 
 151 
 
 239 
 
 301 
 
 380 
 
 605 
 
 963 
 
 1530 
 
 1930 
 
 2435 
 
 3060 
 
 3865 
 
 24 
 
 26 
 
 
 139 
 
 221 
 
 278 
 
 352 
 
 560 
 
 890 
 
 1412 
 
 1760 
 
 2250 
 
 2830 
 
 3562 
 
 26 
 
 28 
 
 
 129 
 
 205 
 
 258 
 
 326 
 
 518 
 
 824 
 
 1320 
 
 1650 
 
 2085 
 
 2620 
 
 3310 
 
 28 
 
 30 
 
 
 120 
 
 191 
 
 241 
 
 304 
 
 485 
 
 770 
 
 1223 
 
 1541 
 
 1950 
 
 2450 
 
 3090 
 
 30 
 
 32 
 
 
 
 179 
 
 226 
 
 285 
 
 455 
 
 724 
 
 1145 
 
 1445 
 
 1825 
 
 2300 
 
 2900 
 
 32 
 
 34 
 
 
 
 168 
 
 213 
 
 269 
 
 427 
 
 680 
 
 1080 
 
 1360 
 
 1720 
 
 2163 
 
 2730 
 
 34 
 
 36 
 
 
 
 160 
 
 201 
 
 254 
 
 405 
 
 644 
 
 1020 
 
 1290 
 
 1625 
 
 2045 
 
 2580 
 
 36 
 
 38 
 
 
 
 151 
 
 190 
 
 240 
 
 383 
 
 610 
 
 965 
 
 1220 
 
 1540 
 
 1935 
 
 2440 
 
 38 
 
 40 
 
 
 
 143 
 
 181 
 
 228 
 
 364 
 
 578 
 
 917 
 
 1158 
 
 1460 
 
 1840 
 
 2320 
 
 40 
 
 42 
 
 
 
 
 172 
 
 217 
 
 346 
 
 550 
 
 875 
 
 1101 
 
 1392 
 
 1755 
 
 2210 
 
 42 
 
 44 
 
 
 
 
 164 
 
 208 
 
 331 
 
 525 
 
 835 
 
 1053 
 
 1330 
 
 1672 
 
 2110 
 
 44 
 
 46 
 
 
 
 
 157 
 
 198 
 
 315 
 
 500 
 
 795 
 
 1003 
 
 1265 
 
 1595 
 
 2010 
 
 46 
 
 48 
 
 
 
 
 151 
 
 190 
 
 303 
 
 481 
 
 765 
 
 965 
 
 1215 
 
 1532 
 
 1931 
 
 48 
 
 50 
 
 
 
 
 145 
 
 182 
 
 290 
 
 462 
 
 734 
 
 925 
 
 1170 
 
 1470 
 
 1855 
 
 50 
 
 52 
 
 
 
 
 
 175 
 
 279 
 
 443 
 
 703 
 
 887 
 
 1120 
 
 1410 
 
 1775 
 
 52 
 
 54 
 
 
 
 
 
 169 
 
 269 
 
 427 
 
 680 
 
 855 
 
 1070 
 
 1360 
 
 1715 
 
 54 
 
 56 
 
 
 
 
 
 163 
 
 259 
 
 412 
 
 655 
 
 825 
 
 1040 
 
 1312 
 
 1655 
 
 56 
 
 58 
 
 
 
 
 
 157 
 
 250 
 
 398 
 
 633 
 
 798 
 
 1010 
 
 1270 
 
 1600 
 
 58 
 
 60 
 
 
 
 
 
 152 
 
 242 
 
 385 
 
 612 
 
 770 
 
 975 
 
 1225 
 
 1545 
 
 60 
 
 62 
 
 
 
 
 
 
 235 
 
 373 
 
 594 
 
 747 
 
 945 
 
 1188 
 
 1500 
 
 62 
 
 64 
 
 
 
 
 
 
 227 
 
 362 
 
 575 
 
 725 
 
 915 
 
 1150 
 
 1450 
 
 64 
 
 66 
 
 
 
 
 
 
 220 
 
 350 
 
 556 
 
 700 
 
 886 
 
 1130 
 
 1405 
 
 66 
 
 68 
 
 
 
 
 
 
 213 
 
 338 
 
 539 
 
 679 
 
 856 
 
 1080 
 
 1360 
 
 68 
 
 70 
 
 
 
 
 
 
 207 
 
 329 
 
 524 
 
 661 
 
 835 
 
 1050 
 
 1325 
 
 70 
 
 72 
 
 
 
 
 
 
 201 
 
 320 
 
 510 
 
 643 
 
 810 
 
 1020 
 
 1286 
 
 72 
 
 74 
 
 
 
 
 
 
 196 
 
 312 
 
 495 
 
 625 
 
 788 
 
 992 
 
 1250 
 
 7 
 
 76 
 
 
 
 
 
 
 191 
 
 304 
 
 483 
 
 610 
 
 770 
 
 967 
 
 1226 
 
 76 
 
 78 
 
 
 
 
 
 
 186 
 
 296 
 
 471 
 
 594 
 
 750 
 
 945 
 
 1190 
 
 78 
 
 80 
 
 
 
 
 
 
 181 
 
 288 
 
 459 
 
 578 
 
 730 
 
 919 
 
 1160 
 
 80 
 
 NOTE. To determine maximum return amperes in common wire, add the 
 amperes taken by all functions likely to be operated at the same time. 
 
310 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 RELATIVE COMPARISON OF COPPER AND ALUMINUM 
 CONDUCTORS 
 
 
 OF EQUAL LENGTH 
 AND CROSS SECTION 
 
 OP EQUAL LENGTH AND CONDUCTIVITY 
 
 
 Conduc- 
 tivity 
 
 Resist- 
 ance 
 
 Cross 
 Section 
 
 Weight 
 
 Tensile 
 Strength 
 
 Cost 
 
 Copper 
 
 100 
 
 100 
 
 100 
 
 100.0 
 
 100.0 
 
 100 
 
 Aluminum 
 
 54 
 
 185 
 
 180 
 
 54.0 
 
 85.1 
 
 185 
 
 Aluminum 
 
 55 
 
 182 
 
 176 
 
 53.0 
 
 83.5 
 
 189 
 
 Aluminum 
 
 56 
 
 179 
 
 173 
 
 52.0 
 
 82.0 
 
 192 
 
 Aluminum 
 
 57 
 
 175 
 
 170 
 
 51.1 
 
 80.6 
 
 196 
 
 Aluminum 
 
 58 
 
 172 
 
 167 
 
 50.2 
 
 79.2 
 
 199 
 
 Aluminum 
 
 59 
 
 169 
 
 164 
 
 49.4 
 
 77.9 
 
 203 
 
 Aluminum 
 
 60 
 
 167 
 
 162 
 
 48.6 
 
 76.6 
 
 206 
 
 Aluminum 
 
 61 
 
 164 
 
 159 
 
 47.8 
 
 75.3 
 
 210 
 
 Aluminum 
 
 62 
 
 161 
 
 157 
 
 47.0 
 
 74.1 
 
 213 
 
 Aluminum 
 
 63 
 
 159 
 
 154 
 
 46.3 
 
 72.9 
 
 216 
 
 CARRYING CAPACITY OF INTERIOR CONDUCTORS 
 
 NATIONAL ELECTRICAL CODE 
 
 B. and 8. Gauge 
 Copper 98% Con. 
 
 CONCEALED RUBBER 
 COVERED WIRES 
 
 EXPOSED WEATHERPROOF 
 WIRES 
 
 Amperes 
 
 Amperes 
 
 0000 
 
 210 
 
 312 
 
 000 
 
 177 
 
 262 
 
 00 
 
 150 
 
 220 
 
 
 
 127 
 
 185 
 
 1 
 
 107 
 
 156 
 
 2 
 
 90 
 
 131 
 
 4 
 
 65 
 
 92 
 
 6 
 
 46 
 
 65 
 
 8 
 
 33 
 
 46 
 
 9 
 
 28 
 
 38 
 
 10 
 
 24 
 
 32 
 
 12 
 
 17 
 
 23 
 
 14 
 
 12 
 
 16 
 
 16 
 
 6 
 
 8 
 
 NOTE. Permissible heating only considered in above figures. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 311 
 
 DIMENSIONS OF RAILWAY SIGNAL ASSOCIATION STANDARD 
 RUBBER-COVERED COPPER WIRE 
 
 Size of Wire 
 B. & S. Gauge 
 
 Diameter of 
 Wire 
 Inch 
 
 Thickness of 
 Insulation 
 Inch 
 
 Thickness of 
 One Braid 
 Inch 
 
 Total 
 Diameter 
 Inch 
 
 
 
 2 *4t 
 
 %4 
 
 %4 
 
 *%4 
 
 1 
 
 19 /64 
 
 %4 
 
 %4 
 
 8 %4 
 
 2 
 
 17 /64 
 
 %4 
 
 %4 
 
 8 %4 
 
 4 
 
 13 /64 
 
 %4 
 
 2 /84 
 
 2 %4 
 
 6 
 
 10 /64 
 
 %4 
 
 2 /64 
 
 2 %4 
 
 8 
 
 %4 
 
 %4 
 
 %4 
 
 24/ 64 
 
 9 
 
 %4 
 
 %4 
 
 %4 
 
 2 V64 
 
 10 
 
 %4 
 
 %4 
 
 %4 
 
 2 %4 
 
 12 
 
 %4 
 
 %4 
 
 %4 
 
 19 /64 
 
 14 
 
 y 8 4 
 
 %4 
 
 %4 
 
 18 /64 
 
 16 
 
 %4 
 
 %4 
 
 %4 
 
 15 /4 
 
 NOTE. For each additional braid add four sixty-fourths inches to total 
 diameter. For each layer of tape add two sixty-fourths inches to total 
 diameter. 
 
 DIMENSIONS OF MANUFACTURER'S ENGINEERS' STANDARD 
 RUBBER-COVERED COPPER WIRE 
 
 Size of Wire 
 B. & S. Gauge 
 
 Diameter of 
 Wire 
 Inch 
 
 Thickness of 
 Insulation 
 Inch 
 
 Thickness of 
 One Braid 
 Inch 
 
 Thickness of 
 One Tape 
 Inch 
 
 Total 
 Diameter 
 
 
 
 21 /64 
 
 %4 
 
 %4 
 
 Vef 
 
 4 %4 
 
 1 
 
 19 /64 
 
 %4 
 
 %4 
 
 Ve4 
 
 *V64 
 
 2 
 
 17 /64 
 
 %4 
 
 %4 
 
 V64 
 
 8 %4 
 
 4 
 
 !%4 
 
 %4 
 
 %4 
 
 V64 
 
 8 V64 
 
 6 
 
 10 /64 
 
 %4 
 
 %4 
 
 %4 
 
 2 %4 
 
 8 
 
 %4 
 
 %4 
 
 %4 
 
 %4 
 
 2 %4 
 
 9 
 
 7 /64 
 
 %4 
 
 %4 
 
 64 
 
 2 %4 
 
 10 
 
 %4 
 
 %4 
 
 %4 
 
 fei 
 
 22 /64 
 
 12 
 
 %4 
 
 %4 
 
 %4 
 
 V64 
 
 2 V64 
 
 14 
 
 %4 
 
 %4 
 
 %4 
 
 V64 
 
 2 %4 
 
 16 
 
 %4 
 
 V64 
 
 2^ 
 
 %4 
 
 17 /64 
 
 NOTE. For each additional braid add four sixty-fourths inches to total 
 diameter. For each additional layer of tape add two sixty-fourths inches 
 to total diameter. 
 
TRUNKING, JUNCTION BOXES AND 
 SUPPORTS 
 
 EXTRACT FROM R. S. A. SPECIFICATION FOR 
 
 ELECTRIC INTERLOCKING (1910) 
 700. TRUNKING 
 Material. 
 
 (/) Trunking, when on stakes above ground and run- 
 ning parallel with the track, shall not be placed nearer 
 than six (6) feet from the gauge side of the nearest rail 
 except by special permission. 
 
 (gr) Local conditions shall determine the height of 
 trunking when above ground; in general, when trunking 
 is run parallel with the tracks, bottom of trunking shall 
 be placed approximately six (6) inches above ground. 
 
 (i) Nails shall not be driven through the trunking from 
 the inside of the groove nor shall they be driven into the 
 groove from the outside. 
 
 (/) Inside corner of trunking, at turns, must be rounded 
 to prevent insulation on wires being injured. 
 
 (fc) Surfaces of trunking that are to be painted shall be 
 finished. 
 
 (Z) Not less than one-third (MO of the capacity of the 
 groove shall remain free for the further installation of 
 wires. 
 
 (ri) As specified, capping shall be securely fastened to 
 
 trunking with { gat Jj oks JGate hooks may be used on 
 main runs of trunking and nails on cross leads. 
 
 703. JOINTS IN TRUNKING 
 
 (a) Unless otherwise specified, joints in grooved trunk- 
 ing shall be lapped, the ends of trunking being beveled at 
 an angle of forty-five (45) degrees. 
 
 (6) Joints in built-up trunking shall be staggered. 
 
 (e) Joints in capping shall be made at least one (1) 
 foot from joints in trunking. 
 
 705. TRUNKING SUPPORTS 
 Material. 
 
 (a) Stakes shall be made of three (3) 
 
 inches by four (4) inches, or of equivalent circular sec- 
 tion and of sufficient length to allow them to be placed at 
 least two (2) feet in the ground. When, due to local re- 
 quirements, stakes of a greater length than three (3) feet 
 six (6) inches, or a greater cross section than three (3; 
 inches by four (4) inches will be necessary, information as 
 to the number, length, and cross section will be furnished 
 by the Purchaser to the Contractor. 
 
ELECTRIC INTERLOCKING HANDBOOK 313 
 
 Field work. 
 
 (6) Trunking above ground shall be supported on stakes 
 placed not more than five (5) feet centers. 
 
 (d) Stakes supporting trunking shall be placed verti- 
 cally and extend at least two (2) feet below the surface of 
 the ground, unless otherwise specified. 
 
 (e) A piece of capping eight (8) inches long and the 
 width of the trunking shall be placed between the trunk- 
 ing and each stake. 
 
 (/) Each joint in the bottom of the trunking shall be 
 supported by a stake. 
 
 710. JUNCTION BOXES 
 
 Material. 
 
 (a) Junction boxes shall be made of and 
 
 so designed that terminals will be kept dry. Each junc- 
 tion box shall be fitted with a cover, hasp, and staple. 
 
 (6) Where ten (10) or less wires are used, junction 
 boxes shall be sixteen (16) inches square by twenty (20) 
 inches deep, inside dimensions, and shall be increased six 
 (6) inches in length for each ten (10) additional connec- 
 tions or fraction thereof made in the box. 
 Field work. 
 
 (c) Junction boxes shall be located as shown on 
 
 drawing and at a height 
 
 sufficient to allow terminals to be placed at least six (6) 
 inches above top of trunking. 
 
 (d) Junction boxes shall be supported in the same 
 manner as the trunking. 
 
314 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TABLE FOR DETERMINING REQUIRED SIZE OF TRUNKING 
 
 TRUNKING 
 
 RUBBER-COVERED COPPER WIRE 
 R. S. A. SPECIFICATIONS 
 
 Size 
 See 
 Fig. 270 
 
 Size of 
 Groove 
 Inches 
 
 Area of 
 Groove 
 Sq. in. 
 
 No. 
 
 
 No. 
 1 
 
 No. 
 
 2 
 
 No. 
 
 4 
 
 No. 
 6 
 
 No. 
 8 
 
 No. 
 9 
 
 No. 
 10 
 
 No. 
 12 
 
 No. 
 14 
 
 No. 
 16 
 
 1 
 
 1 xl 
 
 1.00 
 
 1 
 
 1 
 
 1 
 
 2 
 
 3 
 
 3 
 
 4 
 
 5 
 
 5 
 
 5 
 
 7 
 
 2 
 
 1% x iy 2 
 
 1.87 
 
 2 
 
 2 
 
 3 
 
 5 
 
 6 
 
 6 
 
 8 
 
 9 
 
 9 
 
 10 
 
 14 
 
 3 
 
 1 x2 
 
 2.00 
 
 2 
 
 2 
 
 3 
 
 8 
 
 6 
 
 7 
 
 9 
 
 10 
 
 10 
 
 11 
 
 15 
 
 4 
 
 iy 2 xiy 2 
 
 2.25 
 
 2 
 
 3 
 
 3 
 
 6 
 
 7 
 
 8 
 
 10 
 
 11 
 
 11 
 
 12 
 
 17 
 
 5 
 
 iy 2 x 1% 
 
 2.62 
 
 2 
 
 3 
 
 4 
 
 6 
 
 8 
 
 9 
 
 12 
 
 13 
 
 13 
 
 14 
 
 19 
 
 6 
 
 1V 2 X2 
 
 3.00 
 
 3 
 
 4 
 
 4 
 
 7 
 
 9 
 
 10 
 
 13 
 
 14 
 
 15 
 
 16 
 
 22 
 
 7 
 
 1% x 1% 
 
 3.06 
 
 3 
 
 4 
 
 5 
 
 7 
 
 9 
 
 10 
 
 14 
 
 14 
 
 15 
 
 16 
 
 22 
 
 8 
 
 2 x2 
 
 4.00 
 
 4 
 
 5 
 
 6 
 
 10 
 
 12 
 
 13 
 
 17 
 
 18 
 
 19 
 
 21 
 
 28 
 
 9 
 
 iy 2 x3 
 
 4.50 
 
 4 
 
 6 
 
 7 
 
 11 
 
 13 
 
 15 
 
 20 
 
 21 
 
 23 
 
 24 
 
 33 
 
 10 
 
 2 x3 
 
 6.00 
 
 6 
 
 8 
 
 9 
 
 15 
 
 18 
 
 21 
 
 27 
 
 28 
 
 30 
 
 33 
 
 44 
 
 11 
 
 2 x4 
 
 8.00 
 
 8 
 
 10 
 
 12 
 
 19 
 
 23 
 
 27 
 
 35 
 
 37 
 
 39 
 
 42 
 
 57 
 
 12 
 
 2 x6 
 
 12.00 
 
 12 
 
 15 
 
 18 
 
 29 
 
 35 
 
 40 
 
 53 
 
 56 
 
 59 
 
 64 
 
 86 
 
 NOTE. Table based on 
 maximum capacity. 
 
 wires filling trunking to 75 per cent, of its 
 
 TABLE FOR DETERMINING REQUIRED SIZE OF CONDUIT 
 
 CONDUIT 
 
 RUBBEB-COVERED COPPER WIRE. R. S. A. SPECIFICATIONS 
 
 Inside 
 Diam. 
 
 Area 
 Inside 
 
 No. 
 
 
 1 
 
 No. 
 
 1 
 
 1 
 
 No. 
 2 
 
 No. 
 4 
 
 No. 
 6 
 
 2 
 
 No. 
 8 
 
 No. 
 9 
 
 No. 
 10 
 
 No. 
 12 
 
 No. 
 14 
 
 No. 
 16 
 
 Inch 
 
 Sq. In. 
 
 1 
 
 .785 
 
 1 
 
 2 
 
 2 
 
 3 
 
 3 
 
 4 
 
 4 
 
 5 
 
 iy a 
 
 1.77 
 
 2 
 
 2 
 
 2 
 
 4 
 
 5 
 
 5 
 
 7 
 
 8 
 
 8 
 
 9 
 
 12 
 
 2 
 
 3.14 
 
 3 
 
 3 
 
 4 
 
 7 
 
 8 
 
 10 
 
 12 
 
 13 
 
 14 
 
 15 
 
 21 
 
 2y 2 
 
 4.91 
 
 4 
 
 5 
 
 7 
 
 11 
 
 13 
 
 15 
 
 20 
 
 21 
 
 22 
 
 24 
 
 32 
 
 3 
 
 7.07 
 
 6 
 
 8 
 
 10 
 
 16 
 
 19 
 
 22 
 
 28 
 
 30 
 
 32 
 
 35 
 
 47 
 
 3% 
 
 9.62 
 
 9 
 
 11 
 
 13 
 
 21 
 
 26 
 
 30 
 
 38 
 
 41 
 
 43 
 
 47 
 
 63 
 
 4 
 
 12.57 
 
 11 
 
 14 
 
 18 
 
 28 
 
 34 
 
 39 
 
 50 
 
 54 
 
 56 
 
 62 
 
 83 
 
 . Table based on wires filling conduit to 75 per cent, of its 
 maximum capacity. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 315 
 
 JT V> 
 
 5i3e 1 
 j> Capping 250' BM 
 
 Capping 417' BM T Ki "9 MO'BM 
 Trunking 1000'BM 
 
 Capping 417 'BM 
 TrunKing 667 'BM 
 
 -4.- 
 5*364 
 Capping 417 'BM 
 Trunking 1000'BM 
 
 Capping 417 'BM 
 Trunking JOOO'BM 
 
 Capping 500 BM 
 TrunKing 1000 1 BM 
 
 Capping 500' BM 
 Trunking 1000' BM 
 
 Capping 333' BM 
 TTunkmg 6S7'BM 
 
 Capping 750'BM 
 TrunKing 1500' BM 
 
 5136 10 
 
 Capping 750' BM 
 TrunKing 2000' BM 
 
 E 
 
 
 ?V 
 
 7" . 
 
 5136 11 
 Capping 675' BM 
 TrunKing lbfe7'BM 
 
 Copping 1667 'BM 
 TrunKing ' 
 
 Fia. 270. TBUNKING SECTIONS 
 
 Dimensions as shown are for rough sawed trunking and capping before 
 surfacing. To determine finished dimensions deduct one-eighth inch from 
 each side to be surfaced. Amounts of board feet are for 1,000 hneal feet. 
 
316 GENERAL RAILWAY SIGNAL COMPANY 
 
 JUNCTION BOX 
 Fio. 271. TRUNKING AND JUNCTION Box CONSTRUCTION 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 2 1 
 
 ! g 
 
 S 
 
 1! 
 
 i 
 
 c^i 10 o 10 o 10 c^ 
 
 u O 
 
 po | 
 
 o 
 
 coo 
 coco 
 
 lO^H 
 
 00 
 
 CO 
 
 00 7!-* 
 
 * 1 
 
 o 
 
 00 
 
 
 
 CO O 1 - 1 
 
 & 
 
 <n 
 
 t^T^ 
 
 CO 
 
 q 
 
 
 
 
 coo 
 
 ^ 
 
 ^ 
 
 
 
 COrH 
 
 
 
 
 
 
 . . 
 
 
 1 1 
 
 d '3 
 
 o 
 
 
 . . 
 
 . 
 
 '1 '1 
 
 1" 1" 
 
 ~ 
 
 
 
 
 i " 5 ' o 
 
 
 
 
 
 
 
 8"^ ^*T3 * * 
 
 H 
 
 
 
 
 
 1! II :: 
 
 1 
 
 
 
 . 
 
 a| i| 
 
 "o 
 
 
 
 
 
 .*. G+J 
 
 4) 
 
 
 
 
 ^tf 8^ 
 
 i 
 
 
 rfj 
 
 . 
 
 ! Jj3 -CJ3 jo ' 
 
 
 tf 
 
 ^1 
 
 
 2 S .as '^ ' 
 
 
 '3 
 d 
 
 d d 
 
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 Material 
 
 trunking, . . 
 
 trunking, . . 
 
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318 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 FIG. 272. G. R. S. SPLIT ELBOW FOR CONDUIT 
 
 DIMENSIONS OF SPLIT ELBOW 
 
 Size 
 Conduit 
 
 DIMENSIONS 
 
 A 
 
 B 
 
 C 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 2 
 
 2^6 
 
 2tte 
 
 2% 
 
 2y 2 
 
 210/32 
 
 2i% 8 
 
 Sfe 
 
 3 
 
 3% B 
 
 3%a 
 
 3% 
 
SECTION XIV 
 
 PORTLAND CEMENT CONCRETE 
 
 COVERING DESCRIPTION OF CLASSES 
 OF CONCRETE, METHODS OF MIXING, 
 AND TABLES OF VOLUMES OF MATE- 
 RIALS REQUIRED 
 
PORTLAND CEMENT CONCRETE 
 STORING 
 
 IN storing cement, wooden blocks should be placed on the 
 floor and covered with boards ; the bags of cement should be 
 piled on this to a depth of six or eight layers, keeping 
 the piles six or eight inches away from the walls of the 
 building so as to obtain a free circulation of air on all sides. 
 The cement should be covered with canvas or roofing paper. 
 
 The place chosen for storing the cement should be as dry as 
 possible, as cement absorbs moisture from the atmosphere 
 with great readiness, soon becoming lumpy or even a solid 
 mass if the storehouse is at all damp. In this condition it is 
 useless and should be thrown away. Lumps caused by 
 pressure while being stored must not be mistaken for cement 
 that has been wet and has then hardened; lumps caused by 
 pressure are easily broken, the cement being perfectly good. 
 
 Portland cement is shipped in paper bags or cloth sacks, 
 the second means being recommended as best for the average 
 user. 
 
 PROPORTIONS OP MATERIALS FOR CONCRETE 
 
 A Rich Mixture, with proportions of 1 : 1% : 3, is used for 
 columns or other structural parts subjected to high stresses 
 or requiring exceptional water-tightness. 
 
 A Standard Mixture, with proportions of 1 : 2 : 4, is used for 
 reinforced floors, beams, and columns, for arches, for rein- 
 forced engine or machine foundations subject to vibrations, 
 for tanks, sewers, conduits and other water-tight work. 
 
 A Medium Mixture, with proportions of 1 : 2% : 5, is used for 
 ordinary machine foundations, retaining walls, abutments, 
 piers, thin foundation walls, building walls, ordinary floors, 
 sidewalks and sewers with heavy walls. 
 
 A Lean Mixture, with proportions of 1 : 3 : 6 and 1 : 4 : 8, is 
 used for unimportant work in masses, for heavy walls, for 
 large foundations supporting a stationary load and for stone 
 masonry backing. 
 
 CONSISTENCY OF CONCRETE 
 
 A Medium or Quaking Mixture, of a tenacious, jelly-like con- 
 sistency which quakes on ramming, shall be used for ordinary 
 mass concrete, such as foundations, heavy walls, large arches, 
 piers and abutments. 
 
 A Wet or Mushy Concrete, so soft that it will not require 
 ramming, shall be used for rubble concrete, and for reinforced 
 concrete, such as thin building walls, columns, doors, con- 
 duits and tanks. 
 
 A Dry Concrete, of the consistency of damp earth, may be 
 employed in damp locations for mass foundations, which must 
 stand severe compressive strain within one month after placing, 
 providing it is spread in six inch layers and rammed 
 
322 GENERAL RAILWAY SIGNAL COMPANY 
 
 until water flushes to the surface. Dry mixed concrete shall 
 never be employed with steel reinforcement. 
 
 MIXING CONCRETE BY HAND 
 
 For mixing concrete by hand, a water-tight platform is 
 recommended on which is first spread the sand and then the 
 required amount of cement. Two or more laborers, an 
 even number working on each side of the board, should syste- 
 matically turn the cement into the sand with a slight "flip" 
 on leaving the shovel, being sure to cut to the bottom of the 
 pile at each stroke. This operation will have moved the loca- 
 tion of the pile about two feet. Reversing the direction of 
 the operation brings the pile to its original position, but in a 
 mixed condition. By cutting into the pile with a shovel, an 
 idea of the uniformity of mixing can easily be obtained; the 
 appearance of streaks indicates the need for another turning. 
 If the mixture is of uniform color, the required amount of 
 stone may be distributed over the pile, which should be turned 
 in the same manner until thoroughly mixed. Water is then 
 added and the mass again turned until the desired consistency 
 is secured. 
 
 MIXING CONCRETE BY MACHINE 
 
 Recent experiments conducted on the strength of machine 
 concrete mixed for varying periods indicate that the materials 
 must remain in agitation with the water for at least a full 
 minute. The tendency to rush work is not productive of good 
 concrete, and should, consequently, be curbed. In general, 
 machine mixing where carefully controlled is superior to hand 
 work, since fatigue of the workman has no influence upon the 
 thoroughness of mixing. 
 
 CAUTIONS 
 
 On adding water to the dry cement it becomes a soft, sticky 
 paste, and will remain so for about one-half hour, after 
 which it begins to harden or "set." To disturb the concrete 
 after this initial set has started means a decided loss in strength, 
 while to disturb it after the set is well under way means to 
 destroy the concrete. It should, therefore, be remembered 
 that Portland cement concrete must be placed in position 
 within twenty or thirty minutes from the time after it is 
 first wet. 
 
 A green cement mixture, which can be easily frozen at a 
 temperature below 32 degrees Fahr., should be protected 
 from exposure by placing canvas or roofing paper over the 
 form and covering this with four or five inches of earth or 
 straw. Freezing does not materially affect the binding qualities 
 of good Portland cement, provided the concrete is not sub- 
 jected to alternate freezing and thawing, does not freeze 
 until after placing, and is not subjected to any load until 
 it has been thawed out and allowed to "set" in the usual 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 323 
 
 way. It is safest to avoid mixing on days when the tem- 
 perature is below the freezing point, that is 32 degrees 
 Fahr. If it is necessary, however, to make concrete under 
 these conditions, the sand, water and stone should be heated, 
 and if the cold is severe, salt should be added in proportions of 
 two pounds to each cubic yard of concrete. 
 
 EDITOR'S NOTE 
 
 Above article based on data furnished by Universal Portland 
 Cement Company. 
 
 FIG. 273. MEASURING Box 
 
 DIMENSIONS OF MEASURING BOXES FOR TWO BAG 
 BATCH OF CONCRETE 
 
 PROPORTIONS 
 
 SIZE OF MEASURING Box 
 
 
 
 
 Sand 
 
 Stone or Gravel 
 
 Cement 
 (2 bags) 
 
 Sand 
 
 or 
 
 A 
 
 B 
 
 C 
 
 A 
 
 B | C 
 
 
 
 
 Ft. In. 
 
 Ft. In. 
 
 In. 
 
 Ft. In. 
 
 Ft. In. 
 
 In. 
 
 1 
 
 Itt 
 
 3 
 
 3-0 
 
 2-0 
 
 6 
 
 3-0 
 
 2-0 
 
 12 
 
 1 
 
 2 
 
 3 
 
 4-0 
 
 2-0 
 
 6 
 
 3-0 
 
 2-0 
 
 12 
 
 1 
 
 2 
 
 4 
 
 4-0 
 
 2-0 
 
 6 
 
 4-0 
 
 2-0 
 
 12 
 
 1 
 
 2y 2 
 
 4 
 
 4-0 
 
 2-6 
 
 6 
 
 4-0 
 
 2-0 
 
 12 
 
 1 
 
 2V 2 
 
 5 
 
 4-0 
 
 2-6 
 
 6 
 
 4-0 
 
 2-6 
 
 12 
 
 1 
 
 3 
 
 5 
 
 4-0 
 
 3-0 
 
 6 
 
 4-0 
 
 2-6 
 
 12 
 
 1 
 
 3 
 
 6 
 
 4-0 
 
 3-0 
 
 6 
 
 4-0 
 
 3-0 
 
 12 
 
324 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 VOLUME OF COMPACTED STONE OR GRAVEL CONCRETE 
 PER SACK OF CEMENT 
 
 PROPORTIONS 
 
 QUANTITIES 
 
 Cement 
 
 Sand 
 
 Gravel or 
 Stone 
 
 Cement 
 Sacks 
 
 Sand 
 
 Gravel or 
 Stone 
 
 Concrete 
 
 Cu. Ft. 
 
 Cu. Ft. 
 
 Cu. Ft 
 
 1 
 
 1% 
 
 3 
 
 1 
 
 1.5 
 
 3.0 
 
 3.52 
 
 1 
 
 2 
 
 3 
 
 1 
 
 2.0 
 
 3.0 
 
 3.90 
 
 1 
 
 2 
 
 4 
 
 1 
 
 2.0 
 
 4.0 
 
 4.48 
 
 1 
 
 2% 
 
 4 
 
 1 
 
 2.5 
 
 4.0 
 
 4.85 
 
 1 
 
 2V 2 
 
 5 
 
 1 
 
 2.5 
 
 5.0 
 
 5.45 
 
 1 
 
 3 
 
 5 
 
 1 
 
 3.0 
 
 5.0 
 
 5.80 
 
 1 
 
 3 
 
 6 
 
 1 
 
 3.0 
 
 6.0 
 
 6.40 
 
 MATERIALS REQUIRED FOR ONE CUBIC YARD OF 
 COMPACTED STONE OR GRAVEL CONCRETE 
 
 PROPORTIONS 
 
 QUANTITIES 
 
 Cement 
 
 Sand 
 
 Stone or 
 Gravel 
 
 Cement 
 
 Sand 
 
 Stone or Gravel 
 
 Sacks 
 
 Cu. Ft. 
 
 Cu. Yds. 
 
 Cu. Ft. 
 
 Cu. Yds. 
 
 1 
 
 1% 
 
 3 
 
 7.64 
 
 11.5 
 
 .43 
 
 23.0 
 
 .85 
 
 1 
 
 2 
 
 3 
 
 6.96 
 
 13.9 
 
 .51 
 
 20.9 
 
 .77 
 
 1 
 
 2 
 
 4 
 
 6.04 
 
 12.1 
 
 .45 
 
 24.2 
 
 .90 
 
 1 
 
 2% 
 
 4 
 
 5.56 
 
 13.9 
 
 .51 
 
 22.2 
 
 .82 
 
 1 
 
 2% 
 
 5 
 
 4.96 
 
 12.4 
 
 .46 
 
 24.8 
 
 .92 
 
 1 
 
 3 
 
 5 
 
 4.64 
 
 13.9 
 
 .51 
 
 23.2 
 
 .86 
 
 1 
 
 3 
 
 6 
 
 4.24 
 
 12.7 
 
 .47 
 
 25.4 
 
 .94 
 
 Stone and gravel considered as having 45 per cent, voids. 
 Tables based on 1 sack cement =:! cubic foot. 
 4 sacks cement = 1 barrel. 
 
 Above quantities may vary 10 per cent, in either direction, depend- 
 ing upon the materials used and the compactness of the concrete. 
 
 Data for above tables from the Universal Portland Cement Company. 
 
ELECTRIC INTERLOCKING HANDBOOK 325 
 
 R. S. A. SPECIFICATIONS FOR PORTLAND CEMENT 
 CONCRETE (1912) 
 
 1. GENERAL 
 
 These specifications are for making concrete as used in 
 signal construction. 
 
 2. CEMENT 
 
 Cement shall be Portland, either American or Foreign, 
 
 which will meet the requirements of the 
 
 specifications. 
 
 3. SAND 
 
 Sand shall be clean, sharp, coarse, and of grains varying 
 in size. It shall be free from sticks and other foreign 
 matter, but it may contain clay or loam not to exceed five 
 (5) per cent. Crusher dust, screened to reject all particles 
 over one-fourth (^4) inch in diameter, may be used instead 
 of sand, if approved by the Engineer. 
 
 4. STONE 
 
 Stone shall be sound, hard, and durable, crushed to sizes 
 not exceeding two (2) inches in any direction. For rein- 
 forced concrete, sizes usually are not to exceed three- 
 fourths (%) inch in any direction, but may be varied to 
 suit character of reinforcing material. 
 
 5. GRAVEL 
 
 Gravel shall be composed of clean pebbles of hard and 
 durable stone of sizes not exceeding two (2) inches in 
 diameter and shall be free from clay and other impurities 
 except sand. When containing sand in any considerable 
 quantity, the amount of sand per unit of volume of gravel 
 shall be determined accurately, to admit of the proper 
 proportion of sand being maintained in- the concrete 
 mixture. 
 
 6. WATER 
 
 Water shall be clean and reasonably clear, free from 
 sulphuric acid or strong alkalies. 
 
 7. MEASURE 
 
 The unit of measure shall be the barrel, which shall be 
 taken as containing three and eight-tenths (3.8) cu. ft. 
 Four (4) bags containing ninety-four (94) pounds of 
 cement each shall be considered the equivalent of one (1) 
 barrel. Fine and coarse aggregates shall be measured 
 separately as loosely thrown into the measuring receptacle. 
 
326 GENERAL RAILWAY SIGNAL COMPANY 
 
 8. DENSITY OF INGREDIENTS 
 
 (a) For pipe carrier foundations and reinforced con- 
 crete, a density proportion based on 1:6 is recommended, 
 i. e., one (1) part of cement to a total of six (6) parts of 
 fine and coarse aggregates measured separately. 
 
 (6) For signal and other foundations made in place a 
 density proportion based on 1:9 is recommended, i. e., one 
 (1) part of cement to a total of nine (9) parts of fine and 
 coarse aggregates measured separately. 
 
 9. MIXING 
 
 (a) Tight platforms shall be provided of sufficient size 
 to accommodate men and materials for progressive and 
 rapid mixing. Batches shall not exceed one (1) cu. yd. 
 and smaller batches are preferable. 
 
 (6) Spread the sand evenly upon the platform, then the 
 cement upon the sand, and mix thoroughly until of an 
 even color. Add all the water necessary to make a thin 
 mortar and spread again; add the gravel if used, and 
 finally the broken stone, both of which, if dry, should first 
 be thoroughly wet down. Turn the mass with shovels or 
 hoes until thoroughly incorporated, and all the gravel and 
 stone is covered with mortar; this will probably require 
 the mass to be turned four (4) times. 
 
 (c) Another approved method, which may be permitted 
 at the option of the Engineer in charge, is to spread the 
 sand, then the cement and mix dry, then the gravel or 
 broken stone. Add water and mix thoroughly as above. 
 
 (d) A machine mixer may be used whenever the volume 
 of work will justify the expense of installing the plant. 
 The necessary requirements for the machine will be that 
 a precise and regular proportioning of materials can be 
 controlled and that the product delivered shall be of the 
 required consistency and thoroughy mixed. 
 
 10. CONSISTENCY 
 
 The concrete will be of such consistency that when 
 dumped in place it will not require much tamping. It 
 shall be spaded down and tamped sufficiently to level off, 
 and the water should rise freely to the surface. 
 
 11. FORMS 
 
 (a) Where necessary, forms shall be well built, substan- 
 tial and unyielding, properly braced, or tied together by 
 means of wire or rods, and shall conform to lines given. 
 
 (b) For all important work, the lumber used for face 
 work shall be dressed on one (1) side and both edges to a 
 uniform thickness and width, and shall be sound and free 
 from loose knots, secured to the studding or uprights in 
 horizontal lines. 
 
ELECTRIC INTERLOCKING HANDBOOK 327 
 
 (c) For backings and other rough work undressed lum- 
 ber may be used. 
 
 (d) Where corners of the masonry and other projections, 
 liable to injury, occur, suitable moldings shall be placed 
 in the angles of the forms to round or bevel them off. 
 
 (e) Lumber once used in forms shall be cleaned before 
 being used again. 
 
 (/) The forms must not be removed within thirty-six 
 (36) hours after all the concrete in that section has been 
 placed. In freezing weather they must remain until the 
 concrete has had a sufficient time to become thoroughly 
 hardened. 
 
 (g) In dry, but not freezing, weather the forms shall be 
 drenched with water before the concrete is placed against 
 them. 
 
 12. DISPOSITION 
 
 (a) Each layer shall be left somewhat rough to insure 
 bonding with the next layer above; and if it be already 
 set, shall be thoroughly cleaned and scrubbed with coarse 
 brushes and water before the next layer is placed upon it. 
 
 (&) Concrete shall be deposited in the molds in layers of 
 uniform thickness throughout. 
 
 (c) The work shall be carried up in sections of convenient 
 length and each section completed without intermission. 
 
 (d) In no case shall work on a section stop within eight- 
 een (18) inches of the top. 
 
 (e) Concrete shall be placed immediately after mixing 
 and any having an initial set shall be rejected. 
 
 13. FACING 
 
 (a) The facing will be made by carefully working the 
 coarse material back from the form by means of a shovel 
 bar or similar tool, so as to bring the excess mortar of the 
 concrete to the face. 
 
 (6) About one (1) inch of mortar (not grout) of the 
 same proportions as used in the concrete may be placed 
 next to the forms immediately in advance of the concrete. 
 
 (c) Care must be taken to remove from the inside of the 
 forms any dry mortar, in order to secure a perfect face. 
 
 14. FINISHING 
 
 (a) After the forms are removed, which should generally 
 be as soon as possible after the concrete is sufficiently 
 hardened, any small cavities or openings in the face shall 
 then be neatly filled with mortar. The entire face shall 
 then be washed with a thin grout of the consistency of 
 whitewash, mixed in the same proportion as the mortar 
 of the concrete. The wash shall be applied with a brush. 
 The earlier the above operations are performed the better 
 will be the result. 
 
328 GENERAL RAILWAY SIGNAL COMPANY 
 
 (6) The top surface of all crank, compensator, well hole, 
 lock, dwarf, and high signal foundations shall be rubbed 
 smooth by hand and shall be true to grade and line. 
 
 15. WATERPROOFING 
 
 Where waterproofing is required, a thin coat of mortar 
 or grout shall be applied for a finishing coat upon which 
 shall be placed a covering of suitable waterproofing mate- 
 rial. 
 
 16. FREEZING WEATHER 
 
 Concrete to be left above the surface of the ground shall 
 not be constructed in freezing weather, except by special 
 instructions. In this case the sand, water and broken 
 stone shall be heated, and in severe cold, salt shall be added 
 in proportion of about two (2) pounds per cu. yd. 
 
 17. REINFORCED CONCRETE 
 
 Where concrete is deposited in connection with metal 
 reinforcing, the greatest care must be taken to insure the 
 coating of the metal with mortar, and the thorough com- 
 pacting of the concrete around the metal. Whenever it 
 is practicable the metal shall be placed in position first. 
 This can usually be done in the case where the metal 
 occurs in the bottoms of the forms, by supporting the 
 metal on transverse wires, or otherwise, and then flushing 
 the bottoms of the forms with cement mortar, so as to get 
 the mortar under the metal, and depositing the concrete 
 immediately afterward. The mortar for flushing the bars 
 shall be composed of one (1) part cement and two (2) parts 
 sand. The metal used in the concrete shall be free from 
 dirt, oil, or grease. All mill scale shall be removed, by 
 hammering the metal, or preferably by pickling the same 
 in a weak solution of muriatic acid. No salt shall be used 
 in reinforced concrete when laid in freezing weather. 
 
SECTION XV 
 
 WRITTEN CIRCUITS 
 
 INCLUDING NOMENCLATURE OF OPER- 
 ATED UNITS, CIRCUITS, AND WIRES, 
 WITH TYPICAL ILLUSTRATIONS 
 
WRITTEN CIRCUITS 
 
 WRITTEN Circuits, as hereafter described, have been de- 
 signed to overcome the faults in the old method of 
 circuit drawing which developed upon attempting its 
 application to large interlocking installations. 
 
 A circuit plan for an interlocking, drawn up by the old 
 method, consisted of a track plan, more or less to scale, on 
 which plan symbols of the various pieces of apparatus were 
 shown, placed as far as possible in their proper relative posi- 
 tions; such points as should be electrically connected were 
 joined by lines representing wires. 
 
 While this method has been of great value in the past and 
 still remains so for typical circuits, automatic signal work and 
 small interlocking plants, the plans run into such size when 
 used for large interlocking installations as to practically 
 prohibit its use in connection with that class of work. 
 
 It is true, furthermore, that a great deal of unnecessary 
 labor is involved in both drawing and deciphering the circuits. 
 For example: The engineer in drawing up such a plan begins 
 with some simple sketches, perhaps using symbols of his own 
 invention. After carefully checking these circuits and assur- 
 ing himself of their correctness, he converts them into the 
 rather elaborate form described above, in which the attempt 
 to keep down the size of the plan is very apt to result in a 
 cramped arrangement of apparatus and a tangle of wires. 
 When the man on maintenance or installation wishes to make 
 use of these circuits, he has to reverse the process and reduce 
 the composite drawing to its simple elements. 
 
 Written circuits have been designed to eliminate this un- 
 necessary work and especially to secure plans in which the 
 complete circuit for any given switch, signal, or other function, 
 can be written on a page of ordinary size without crowding, 
 these pages being bound together in a book which will easily 
 and instantly permit reference to be made to any portion of 
 the wiring of the plant. 
 
 A set of plans drawn up in accordance with this method 
 involves the following : 
 
 1. Location Plan. This shows the relative location of 
 track, interlocking station, switch and signal functions, track 
 relays, switch circuit controllers, etc. Notes, such as for the 
 routing of signal arms, should be included on this plan. 
 
 2. Typical Plan of Special Circuits. This shows what is 
 proposed to be accomplished in route locking, etc., these 
 circuits to be drawn up either by the old method, or in "written" 
 form, as desired. 
 
 3. Typical Plans of Signal Circuits, Switch Circuits, etc. 
 
 4. Special Circuits, made up in "written" form. These 
 special circuits are separated so that circuits not connected 
 together are kept entirely apart from each other, being drawn 
 
332 GENERAL RAILWAY SIGNAL COMPANY 
 
 up on separate sheets. This desirable feature causes the 
 "written" circuits to be exceptionally clear and permits their 
 being readily grasped. 
 
 5. Detail Wiring Plans. It may be helpful under certain 
 conditions to add to the circuits listed above, detail plans 
 showing the wiring for the indicator group and interlocking 
 machine. 
 
 In drawing up such circuits it is necessary to use a nomen- 
 clature for naming the apparatus and to adopt symbols to be 
 used in writing the circuits. A nomenclature of operated units 
 and of circuits, which has been used for some time by the 
 General Railway Signal Company and found thoroughly 
 practicable is given on the following pages. 
 
 On page 337 is given a nomenclature of wires. It is to be 
 understood that this is equally applicable to written circuits 
 or to circuits drawn up by the older methods. 
 
 NOMENCLATURE OF OPERATED UNITS 
 
 A Approach Relay or Indicator. With number as pre- 
 fix, indicating number of principal signal up to which the 
 approach section controlling same leads, as 10A. 
 
 B Positive Battery Wire. Used alone where only one 
 battery voltage is in use. When used with H as a 
 suffix (BH) indicates 110 volt battery. When used with 
 L as a suffix (BL) indicates low voltage battery. When 
 more than one low voltage battery is used with dif- 
 ferent voltage, use number indicating voltage as further 
 suffix, as BL-10, indicating 10 volt battery. 
 
 C Common Wire. Used alone when only one common is 
 in use. When used with H as a suffix (CH) indicates 
 110 volt common. When used with L as a suffix (CL) 
 indicates low voltage common. When more than one 
 high voltage or low voltage common is used, use num- 
 bers as further suffixes. (CH-1, CH-2, CL-1, etc.) 
 
 D Relay or Indicator Controlling the Ninety Degree Posi- 
 tion or Distant Function of a Signal. With prefix indi- 
 cating the number of principal signal which it controls, 
 as 10D, indicating relay or indicator controlling the 
 ninety degree position of signal No. 10, or signal No. 
 10 if it is a distant signal in two position signaling. 
 
 E Special Relay or Indicator (other than T, D, H, K, or F 
 relays and indicators). With number as prefix indi- 
 cating number of principal unit entering into its control, 
 or indicating principal unit which it controls. 
 
 F Relay or Indicator Repeating a Track Relay or Signal. 
 With number as a prefix indicating number of relay or 
 signal which it repeats, as 10F. 
 FP Floor Push. 
 
ELECTRIC INTERLOCKING HANDBOOK 333 
 
 G Switch Indicator. With number of signal governing 
 through block in which switch is located as prefix, as 10G. 
 H Relay or Indicator Controlling Forty-five Degree Position 
 or Home Function of a Signal. With prefix indicating the 
 number of principal signal which it controls, as 10H, indi- 
 cating relay or indicator controlling the forty-five degree 
 position of signal No. 10, or signal No. 10 if it is a home 
 signal in two position signaling. 
 
 J Junction Box or Terminal Board. With arbitrary num- 
 ber as prefix, as 10J. 
 
 K Lock Relay. Used in connection with route or detector 
 locking for interrupting the current supply to switch 
 and derail machines, etc., with number as a prefix, 
 indicating track section affected by it, as 10K. 
 KS Knife Switch. 
 L Lever Lock. With prefix indicating number of lever 
 
 which it locks, as 10L, meaning lock on lever No. 10. 
 LA Lightning Arrester. 
 LC Latch Contact. With prefix indicating number of lever, 
 
 as 10LC. 
 
 M Man-hole. With arbitrary number as prefix, as 10M. 
 PB Push Button or Strap Key. 
 
 PC Pole Changing Relay. With prefix indicating number 
 of signal at which relay is located or number of signal 
 controlled by it. 
 
 S Stick Relay. Used in connection with route locking. 
 With number as prefix, as 10S, meaning stick relay 
 locking route of signal No. 10, or locking operated units 
 in track section 10T, if separate stick relays are used 
 for each track section. 
 
 SL Outlying Switch Lock. With number as prefix indi- 
 cating number of controlling lever. Use arbitrary 
 number if there is no controlling lever. 
 
 T Track Circuit. With number as prefix indicating num- 
 ber of track circuit, as 10T, which is also the name of 
 the track relay for track circuit 10T. 
 
 NOTE. The number for the track circuit is taken from the following in 
 the order given : 
 
 M. P. Frog or 
 
 Switch or 
 
 Derail or 
 
 Arbitrary numbers 01, 02, 03, etc. 
 
 TL Traffic Lock. With prefix indicating number of lever 
 
 which it controls, as 10TL. 
 TP Telephone. 
 TR Time Release. With number as prefix indicating 
 
 principal unit which it releases, as 10TR. 
 V Electric Slot. With number of signal as prefix, as 10V. 
 XB Crossing Bell With arbitrary number as prefix, such 
 
 as 10XB. 
 
334 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 NOMENCLATURE OF CIRCUITS 
 SYMBOLS FOR OPERATED UNITS 
 
 An operated unit (signal, relay, indicator, etc.) is repre- 
 sented by a rectangle with the number and letter of the relay, 
 signal, etc., inside, thus: 
 
 The forty-five degree mechanism of a three-position signal 
 is indicated thus : 
 
 And the ninety degree thus : 
 
 CIRCUIT CONTROLLERS OPERATED BY SWITCH POINTS 
 Closed when switch is normal,. . 
 
 Closed when switch is reversed, . . . 
 
 Closed when switch is normal and 
 locked in position, 
 
 Closed when switch is reversed and 
 locked in position, 
 
 /-Switch Number 
 1O 
 
 CIRCUIT CONTROLLERS OPERATED BY SIGNALS 
 
 '_ jnal Number 
 
 Closed at only, 
 
 Closed at 45 only, 
 
 Closed at 90 only, 
 
 Closed at 60 only, 
 
 Closed between and 45, .... 
 
 Closed between 45 and 90, etc., . . 
 
 10 
 
 45-9O 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 335 
 
 CIRCUIT CONTROLLERS OPERATED BY LEVERS 
 
 N B C D R Symbol 
 
 N Full normal position of lever. 
 B Normal indication position. 
 C Intermediate position. 
 D Reverse indication position. 
 R Full reverse position. 
 
 Heavy horizontal line indicates portion 
 of cycle of lever through which circuit is 
 closed . 
 
 RELAY AND INDICATOR CONTACTS 
 
 Neutral front contact, 
 
 Neutral back contact, 
 
 Normal polarized contact 
 
 Reverse polarized contact, 
 
 Intermediate contact on three-posi- 
 tion relay: Closed when relay is 
 deenergized, 
 
 TIME RELEASE CONTACT 
 
 Normally closed, 
 
 Normally open, 
 
 Relay Number 
 
 1OT 
 JO_T 
 1O T 
 
 tor 
 
 10 T 
 
336 GENERAL RAILWAY SIGNAL COMPANY 
 
 LATCH CONTACT 
 Normally closed, 
 
 Normally open, 
 
 PUSH BUTTON OR STRAP KEY 
 Normally closed, 
 
 Normally open, P B 
 
 KNIFE SWITCH 
 Normally closed, 
 
 Normally open, K s 
 
 TERMINAL IQJ Meaning terminal in junction box 
 
 No. 10 or on terminal board No. 
 10. 
 
 NOTE. Small numbers written as exponents to the right and above 
 relay numbers, lever numbers, etc., indicate contact numbers. 
 
 Relay or indicators contacts are numbered from left to right looking 
 toward the relay. 
 
 GRAPHICAL SYMBOLS FOR CIRCUIT CONTROLLERS 
 OPERATED BY LEVERS 
 
 Model 2, interlocking "machine. 
 
 LEVER CONTACT NUMBERING 
 
 Model 2, interlocking machine. 
 
 BOTTOM TOP 
 
 1357 
 
 M y M 
 
 W W M M 
 
 REVERSE 
 NORMAL 
 
ELECTRIC INTERLOCKING HANDBOOK 337 
 
 NOMENCLATURE OF WIRES 
 
 The matter of primary importance in naming wires is to 
 have a different name for each wire and have it so shown on 
 both the plan and suitable tags attached to the wires: this in 
 order that a wire on the ground may be quickly identified on 
 the plan. 
 
 At the same time it is highly desirable to have a wire nomen- 
 clature system that is suggestive, so as to reduce, as far as 
 possible, the necessity for reference to plans. 
 
 On account of the multitude of circuit combinations possible, 
 a system must be rather elastic. With all of the above taken 
 into consideration, the following is submitted as a practical 
 system of wire nomenclature. 
 
 NOTE. Names of wires are shown on plans in brackets, thus: (10D). 
 Number of cable containing a wire may be written above and at right 
 angles to the wire, thus : o 
 
 I Indication Wire. With number of unit which it indi- 
 cates as prefix, as 101. 
 LL Lighting Wire. 
 N Normal Control Wire. With number of operated unit 
 
 which it controls as prefix, as ION. 
 P Ninety Degree Control Wire. With number of signal as 
 
 prefix, as 10P. 
 
 R Reverse Control Wire. With number of operated unit 
 which it controls as prefix, as 10R. If 10 is a three-position 
 signal, 10R is the name of the forty-five degree control 
 wire. 
 
 V Slot Wire. With number of signal as prefix, as 10V. 
 X Wire going to positive battery through a circuit con- 
 troller on a signal closed in the zero degree position only, 
 with the number of the signal as a prefix, as 10X. 
 Y Wire going to positive battery through a circuit con- 
 troller on a signal closed from zero to forty-five degrees 
 only, with the number of the signal as a prefix, as 10Y. 
 Z Wire going to positive battery through a circuit controller 
 on a signal closed in the clear position if the signal is a 
 two-position signal, or closed from forty-five to ninety 
 degrees if the signal is a three-position signal, with the 
 number of the signal as a prefix, as 10Z. 
 Wires not covered by the above are named as follows : 
 A wire leading from the operating coil of a unit toward 
 battery positive takes the name of this unit, as 10H, meaning 
 the wire from the coil of home control relay for signal No. 10 
 leading to positive. After passing through a circuit controller, 
 it takes the number "1" as a suffix, as 10H1. This suffix 
 number increases by one as the wire successively breaks through 
 additional controllers. 
 
 The wire leading from the operating coil to battery negative, 
 takes the name of the unit with the letter "C" as a prefix, as 
 
338 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 C10H, and after breaking through successive controllers is 
 written C10H1, C10H2, etc. 
 
 The above method applies directly to simple circuits having 
 no branches, thus: 
 
 In cases of branch wiring this method is applied directly to 
 the principal circuit circuit for superior route. The first 
 branch from this circuit takes the suffixes 21, 22, etc., instead 
 of 1, 2, etc. The second branch 41, 42, etc., thus continuing 
 allowing twenty numbers for each branch. 
 
 ^EEE 
 
 ! a 
 
 1000* 
 
 1TR 
 
 BL 
 
 BH 
 
 CH 
 
 Fia. 274. SECTION OF LOCATION PLAN WITH SPECIAL CIRCUITS 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 339* 
 
 ILLUSTRATIONS 
 
 Illustrative of "Written Circuits" and "Wire Nomen- 
 clature," is shown in Fig. 274, a section of an interlocking 
 plant with the special circuits used in connection with such an 
 arrangement. In accordance with the instructions given under 
 " Location Plan" on page 331, the track plan with the rela- 
 tive location of signal and switch functions, track relays and 
 the interlocking station with its indicators, relays, etc., is shown. 
 
 Below the track plan are shown the special circuits drawn 
 up in written form. Referring to the sheets of nomenclature 
 shown on the preceding pages, it will be seen that the circuit 
 
 uz 
 
 L@ i 
 
 FIG. 275. SIGNAL SELECTING CIRCUIT 
 
 shown at the top is for the control of the annunciator for 
 signal No. 1, this taking low voltage battery through front 
 contacts of the track relays for sections 03T and 02T. Sim- 
 ilarly the control of lock 1L takes battery through normally 
 closed contact No. 2 of screw release 1TR, the front point of 
 home relay 3F, the front point of contact No. 2 of stick relay 
 IS and the latch contact of the lock itself; the current after 
 passing through the lock goes to the low voltage common 
 wire. Information regarding the operation of this type of 
 special circuit may be had by reference to the Section on 
 ''Electric Locking Circuits" (page 133). 
 
 f Fig. 275 illustrates the method of writing a signal selecting 
 circuit. This is included principally to show the application of 
 the wire nomenclature to the different branches of the same 
 circuit. The wires of each branch are designated in the same 
 manner as in the principal circuit but with the suffixes 21, 22, 
 23, or 41, 42, 43, etc., these depending upon the order in which 
 the different branches are taken from the principal circuit. 
 
SECTION XVI 
 
 SIGNAL ASPECTS AND SYMBOLS 
 
 COVERING STANDARDS ADOPTED BY 
 THE RAILWAY SIGNAL ASSOCIATION 
 
SIGNAL ASPECTS AND SYMBOLS 
 
 R. S. A. PRINCIPLES OF SIGNAL INDICATIONS 
 
 (1906) 
 
 (a) On all high signals conferring or restricting rights a 
 red light shall be the night indication for STOP. A yellow 
 light shall be the night indication for CAUTION, and a green 
 light the night indication for PROCEED. 
 
 NOTE. The word caution to be used as indicating the function of 
 a distant signal. 
 
 (6) The day indication of semaphore signals shall be 
 given in the upper right-hand quadrant. 
 
 (c) The semaphore arm in the horizontal position shall 
 indicate STOP, inclined upward forty-five (45) degrees, 
 CAUTION, and inclined upward, ninety (90) degrees, 
 
 PROCEED. 
 
 SIGNALING PRACTICE AS DEFINED BY THE 
 
 R. S. A. (1913) 
 MEMORANDUM ON THE ESSENTIALS OF SIGNALING 
 
 Incorporated in the Report of the Committee on Trans- 
 portation of the American Railway Association, May, 1911. 
 
 "The reports of various Committees of the Railway Signal 
 Association and of the American Railway Engineering Asso- 
 ciation on the subject of signaling have been su omitted to this 
 Committee, with the request that the essentials of signaling be 
 outlined or defined for the future guidance of their Committees. 
 
 The subject has been carefully analyzed and considered. 
 There are three signals that are essential in operation and 
 therefore fundamental, viz : 
 
 1. Stop. 
 
 2. Proceed with caution. 
 
 3. Proceed. 
 
 The fundamental, "proceed with caution," may be used 
 with the same aspect to govern any cautionary movement; 
 for example, when : 
 
 (a) Next signal is "stop." 
 
 (6) Next signal is "proceed at low speed." 
 
 (c) Next signal is "proceed at medium speed." 
 
 (d) A train is in the block. 
 
 (e) There may be an obstruction ahead. 
 
 There are two additional indications which may be used 
 where movements are to be made at a restricted speed, viz : 
 
 4. Proceed at low speed. 
 
 5. Proceed at medium speed. 
 
 Where automatic block system rules are in effect, a special 
 mark of some distinctive character should be applied at the 
 stop signal. 
 
344 GENERAL RAILWAY SIGNAL COMPANY 
 
 The Committee therefore recommends : 
 
 SIGNAL FUNDAMENTALS 
 
 1. Stop. 
 
 2. Proceed with caution. 
 
 3. Proceed. 
 
 Supplementary Indications to be Used Where Required. 
 
 4. Proceed at low speed. 
 
 5. Proceed at medium speed. 
 
 Stop signals operated under automatic block system rules 
 should be designated by some distinctive mark to be deter- 
 mined by each road in accordance with local requirements." 
 
 RECOMMENDATIONS OP COMMITTEE I 
 
 Your Committee submits for approval the following two 
 schemes of signaling in conformity with the recommendations 
 of the Committee on Transportation. 
 
 SCHEME No. 1 
 Fundamentals 
 
 1. Stop, 
 
 r 
 
 2. Proceed with caution, 
 
 3. Proceed, 
 
 As means of designating stop signals operated under auto- 
 matic block system rules, the following are suggested : 
 
 1. The use of a number plate; or 
 
 2. The use of a red marker light below and to the left of 
 the active light ; or 
 
 t 3. The use of a pointed blade, the blades of other signals 
 giving the stop indication having square ends ; or 
 4. A combination of these distinguishing features. 
 
ELECTRIC INTERLOCKING HANDBOOK 345 
 
 SCHEME No. 2 
 
 Supplementary 
 Fundamentals Indications 
 
 1. Stop, 
 
 2. Proceed with caution, 
 
 3. Proceed, 
 
 4. Proceed at low speed, 
 
 5. Proceed at medium speed, 
 
 As means of designating stop signals operated under auto- 
 matic block systems rules, the following are suggested: 
 
 1. The use of a number plate; or 
 
 2. The use of a red marker light below and to the left of 
 the active light ; or 
 
 3. The use of a pointed blade, the blades of other signals 
 giving the stop indication having square ends ; or 
 
 4. A combination of these distinguishing features. 
 Having in view the practice of indicating diverging routes 
 
 by several arms on the same mast, the Committee submits 
 for approval the following to establish uniformity in this 
 practice : 
 
346 GENERAL RAILWAY SIGNAL COMPANY 
 
 SCHEME No. 3 
 
 1. Stop, 
 
 or H or 
 
 or 
 
 2. Proceed with caution, 
 
 or 
 
 3. Proceed, 
 
 n 
 
 or 
 
 or 
 
 or 
 
 4. Proceed with caution on low- 
 speed route, 
 
 5. Proceed on low-speed route, . . D or -Q 
 
 6. Proceed with caution on medium- 
 speed route, 
 
 7. Proceed on medium speed route, 
 
ELECTRIC INTERLOCKING HANDBOOK 347 
 
 8. Reduce to medium speed, 
 
 As means of designating stop signals operated under auto- 
 matic block system rules, the following are suggested: 
 
 1. The use of a number plate; or 
 
 2. The use of a red marker light below and to the left of the 
 active light ; or 
 
 3. The use of a pointed blade, the blades of other signals 
 giving the stop indication having square ends ; or 
 
 4. A combination of these distinguishing features. 
 
 The above three schemes are submitted, after an earnest 
 effort to carry out the Committee's instructions to submit a 
 uniform scheme of signaling, with the idea that each scheme 
 is complete in itself. 
 
 SIGNAL DEFINITIONS 
 
 A "non-automatic" signal is one which is in no way con- 
 trolled by track circuit. 
 
 An "automatic" signal is one, the primary control of which 
 is the track circuit, or in other words, it is a signal which 
 automatically gives indication in regard to the integrity of 
 the track through its block. 
 
 A "semi-automatic" signal is a manually controlled auto- 
 matic signal and may, or may not, be interlocked. As to 
 whether it is, or is not, interlocked, will be apparent from its 
 position on the plan and its relation to other signals. It is 
 to be understood that this manual control is direct, and that 
 a signal is not to be considered semi-automatic because some 
 feature of its control is dependent upon another signal which 
 is manually controlled. Tne term "slotted" refers only to a 
 mechanical signal equipped with an electric slot, 
 
 A "stick semi-automatic" signal is a semi-automatic signal 
 which will not clear automatically after it has been put to 
 stop by interruption of the track circuit. It cannot be cleared 
 again until the manually operated device controlling it has 
 been restored normal and reversed once more. 
 
 A "non-stick-automatic" signal operates automatically as 
 long as all contacts (lever, signal, controller, etc.), other than 
 track relay contacts affecting its control, are closed. 
 
348 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. SYMBOLS FOR SIGNALS 
 ^ PLATE 1 (October, 1912). 
 
 OPERATING. 
 
 
 NON -AUTOMATIC. 
 
 SLOTTED. 
 
 (MECM.) 
 
 SEMI-A TOMATIO. 
 
 (POW R.) 
 
 
 SPECIAL 
 
 RIFEMNCI 
 
 TONOTO. 
 
 
 MECHAMGM 
 
 POWER 
 
 STICK. 
 
 NON-STICK 
 
 (POWER) 
 
 
 
 r 
 
 i i 
 
 i z 
 
 -a 
 
 p 
 
 fc] 
 
 
 L:o:2 
 
 Two 
 
 POSITION 
 
 SEMUM 
 
 2-PosmoM. 
 OT0600TOTO 
 OTo7S'Oro90 
 
 i--, 
 j. j 
 
 i A 
 
 M 
 
 A2 
 
 A3 
 
 ^4 
 
 a 
 
 AS 
 
 ID 
 
 A6 
 
 1 A7 
 
 THREE 
 POSITION 
 
 2-PosrriON. 
 OT090 
 
 i B 
 
 33 
 
 Bl 
 
 11 
 B2 
 
 B3 
 
 CD 
 
 B4 
 
 ED 
 
 B5 
 
 XI 
 
 B6 
 
 ta 
 
 B7 
 
 2-PlSITKM. 
 
 OT045 
 
 ! C 
 
 Cl 
 
 C2 
 
 C3 
 
 is 
 
 04 
 
 C5 
 
 S3 
 
 C6 
 
 Isa 
 
 C7 
 
 2-PosmoN. 
 45 TO SO 
 
 $ 
 
 w 
 
 1 01 
 
 1^)2 
 
 1 03 
 
 \ 
 
 h 
 
 Q5i 
 
 1 07 
 
 
 3- POSITION. 
 TO 45 TO 90 
 
 i E 
 
 1" 
 
 1 El 
 
 fa 
 
 1 E2 
 
 ft 
 
 ha 
 
 1 E4 
 
 1 E5 
 
 S 
 
 In 
 
 
 & 
 
 JE25 
 
 NOTE: ARMS SHOULD 'ALWAYS BE SHOWN IN NORMAL POSITION. 
 
 SPECIAL- 3 POSITION NON-AUTOMATIC, TO 45 . 
 SEMI -AUTOMATIC STICK, 45 TO 90. 
 
 SPECIAL- 3 POSITION NON -AUTOMATIC, Oio45. 
 SEMI-AUTOMATIC NON-STICK. 45 TO 90. 
 
 S 1 ABSOLUTE STOP SIGNAL. j <' DISTANT SIGNAL. 
 
 i ! 
 
 ["> PERMISSIVE STOP SIGNAL. C TRAIN ORDER SIG.NAL. 
 
 ENDS OF BLADES IN SYMBOLS ARE TO BE OF THE ACTUAL FORMS USED BY THE 
 ROAO CONCERNED. IF NOT SPECIFIED THE ABOVE FORMS WILL BE USED ON PLANS. 
 
 fTTTTj FIXED ARM. 
 
 t-"-l UPPER 9 UAORWfr SIGNAL. 
 ,"_""] LOWER QUADRANT SIGNAL. 
 
 ;~~] VERTICAL "l 
 
 To""" \ MARKER LIGHTS 
 t , 
 < STAGGERED j 
 
 or" ' 
 
 il 
 
 4 4- ' 
 
 -2 
 
 Ititi 
 
 "iti* 
 
 
 J 
 
 
 
 T 
 
 ^1 
 
 
 
 
 <L> 
 
 v\ \ 
 
 ^_ 
 
 
 
 
 KJ 
 
 DIAGRAMS OF PROPORTIONS FOR MAK- 
 ING SYMBOLS FOR SIGNAL BLADES . 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 349 
 
 R. S. A. SYMBOLS FOR SIGNALS 
 PLATE 2 (October, 1912). 
 
 
 GROUND 
 MAST. 
 
 GROUND MAST WITH 
 BRACKET ATTACHMENT. 
 
 OFFSET 
 BRACKET POST. 
 
 T 
 
 BRACKET 
 POST. 
 
 I:, 
 
 SUSPENDED 
 MAST. 
 
 ^X RING ENCLOSED 
 
 ; CHARACTERISTICS 
 
 MEAN LIGHT SI6NA1 
 ONLY. 
 
 SMASH 
 
 POT SIGNAL. 
 
 Disc SIGNALS. 
 
 () 
 
 HOME HOME DISTANT DISTANT DOUBLE 
 
 PROCEED. STOP. PROCEED. CAUTION. FUNCTIONED. 
 
 PRESENT SIGNAL TO BE REMOVED . 
 
 PRESENT SIGNAL TO REMAIN. 
 
 RELATION OF THE SIGNAL TO THE TRACK AND THE DIRECTION OF TRAFFIC 
 
 RIGHT HAND LOCATIONS. 
 
 RIGHT HAND SIGNAL LEFT HAND SIGNAL. 
 
 LEFT HAND LOCATIONS. 
 
 RIGHT HAND SIGNAL 
 
 LEFT HAND SIGNAL. 
 
350 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. LOCATION SYMBOLS 
 PLATE 3 (October, 1912). 
 
 INSULATING RAIL JOINTS. 
 
 TRACK CIRCUITS IN TRACK CIRCUIT ON TRACK CIRCUIT ON 
 BOTH DIRECTIONS. LEFT . NONE ON RIGHT. RIGHT, NONE ON Lerr. 
 
 IMPEDANCE BOND. TRAFFIC DIRECTION. TRACK PAN. 
 
 1 1 >- V-^V-A^yV^^^V^/ 
 
 STATION. CROSSING GATE. SIGNAL SIGNAL SUB-STATION. 
 
 (UNUSS 8ncrnje jptoneo.) POWER STATION. -- 
 
 - 
 
 
 ) \ > k ) * ( )=* k 
 
 TUNNEL. BRIDGE OR VIADUCT. DRAWBRIDGE. LIFT BRIDGE. 
 
 NOTE: STATJ WMITMIK DH*.HM.r-TMW06 o T*OOSM BmM. 
 
 T T T II ji 
 
 
 ; 
 
 1 I ii 
 
 OVERHEAD SIGNAL HIGHWAY RAILWAY PROPOSED RAILWAY 
 BRIDGE. BIOGE. CROSSING. CROSSING. CROSSING. 
 MOTE: SPtcirr wMtTMM Sn*u w EUCTHIC Rv Cuossiw. 
 
 
 MAIL CRANE. WATER TANK. WATER COLUMN. TRACK INSTRUMENT. TORPEDO MACHINE. 
 
 TRAIN STOPS. 
 
 A A A A A 
 
 \w w U 
 
 ^ STOP. 
 
 
 
 
 < -~iJr *^W 
 
 e, 
 CLEAR. 
 
 NON- AUTOMATIC. SLOTTED. SEMI- 
 MECHANICAL. POWER. AUTOMATIC. 
 
 AUTOMATIC. 
 
 1 ^^^^ f ^^ 1 _^^ 
 
 DO * 
 POWER SWITCH INSULATED TURN-OUT 
 MACHINE. SWITCH ROD. AND SWITCH STAND. 
 
 ^L 
 
 ELECTRIC 
 SWITCH LOCK. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 351 
 
 11. S. A. LOCATION SYMBOLS 
 PLATE 4 (October, 1912). 
 
 RELAY Box. JUNCTION Box. TERMINAL Box. LIGHTNING ARRESTER 
 
 Box. 
 
 $ CAPACITY 
 
 BATTERY CHUTE . 
 
 
 RELAY MX CAPACITY PT\ 
 
 CHUTE CAPACITY kXd 
 
 1 
 
 RELAY Box AND POST. BATTERY CHUTE, RELAY 
 
 Box AND POST COMBINED . 
 
 NOTE : TYPE Of INDICATOR 
 
 TO K COVERED BY 
 
 (_) 6ENERALNDTE. () 
 
 I I 
 
 SWITCH Box LOCATION . SWITCH INDICATOR . 
 
 SWITCH INDICATOR 
 AND SWITCH Box. 
 
 A 
 
 OD 
 
 CABLE POST WITH ONE WITH Two WITH RELAY WITH RELAY WITH RELAY 
 ONLY. INDICATOR. INDICATORS. Box. Box AND ONE Box AND Two 
 
 INDICATOR . INDICATORS . 
 
 5 J ABOVE SURFACE . 
 
 5}- HALF ABOVE SURFACE. 
 
 M5J BCLOW SURFACE. 
 
 (FI6URES INDICATE CAPACITY) 
 
 HIGHWAY CROSSING BELL. 
 
 > BATTERY SHELTER. 
 
 OR 
 
 TRACK BATTERY 
 
352 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. LOCATION SYMBOLS 
 PLATE 5 (October, 1912). 
 
 INTERLOCKED SWITCHES AND DERAILS. 
 
 SWITCH -SET FOR TURN-OUT. 
 
 DERAIL- POINT TYPE-DERAILING. 
 
 SWITCH -SET FOR STRAIGHT TRACK. 
 
 DERAIL- POINT TYPE-NON-DERAIUNG . 
 
 DERAIL -LIFTING RAILTYPE-DERAILING. DERAIL- LIFTING RAILTYPE-NON-DCRAILING. 
 
 DERAIL -LIFTING BLOCK TYPE -DERAILING. DERAIL- LIFTING BLOCK TYPE-NON-DERAIUNG. 
 
 NOTE: NON-INTERLOCKED SWITCHES AND OEKAItS TO BE SHOWN 
 SAME AS ABOVE EXCEPT SHAOIN6 IN TRIANGLES OMITTED. 
 
 RUNS 
 
 OF CONNECTIONS. 
 
 PIPE-WIRE (MECH.). 
 WIRE DUCT. 
 
 COMPRESSED AIR. 
 PIPE-WIRE AND DUCT. 
 PIPE -WIRE AND AIR. 
 DUCT AND AIR. 
 
 PIPE -WlRETDUCT AND AIR. 
 
 BOLT LOCKED SWITCH. 3 " WAY - 
 
 5.LM.-Swircn*LocK MOVEMENT. CRANKS. 
 F.P.L.-FAGING POINT LOCK. J-WAY. 
 
 COMPENSATOR. 
 
 ARROW INDICATES DIRECTION 
 OF MOVEMENT OF PIPE LINE- 
 NORMAL TO REVERSE. 
 
 OIL ENCLOSED PIPE LINE. 
 
 3-WA.Y. 
 
 MAN-HOLE. 
 
 r^Ti INTERLOCKING OR BLOCK STATION. ISZTI 
 
 I/F\I SH9WM6 RELATIVE POSITION OF STATION. OPERATOR AND TRACK. V 1 M 
 OPERATOR FACING TRACK . OPERATOR WITH BACK TO TRACK. 
 
 NOTE: UNLESS OTHERWISE SPECIFIED ON PLAN IT WILL BE ASSUMED THAT WHERE AM 
 
 INTERLOCKED SIGNAL IS SHOWN CLEAR OR A DERAIL SHOWN IN NON-DERAILING 
 
 POSITION THE CONTROLLING LEVER IS REVERSED, AND THAT ALL OTHER LEVERS ARE NORMAL. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 353 
 
 R. S. A. LOCATION SYMBOLS 
 PLATE 6 (October, 1912). 
 
 INTERLOCKED SWITCHES, DERAILS, ETC. 
 
 6 
 
 SINGLE LINE PLAN . 
 EXPLANATION 
 
 1 - SIMPLE TURN-OUT. 
 
 2 - SIMPU CROSS- WER . 
 
 3 - Owftit- POINT Tm . 
 4 -SIMILE SLIP SWITCH. 
 
 5 -DOUBLE SLIP SWITCH. 
 6-MovABu POINT Cnossme Fooe. (M.P.F.) 
 7 -SINGLE SLIP SWITCH WTM M.P.F. 
 8 -DOUBLE SLIP SWITCH WITH M.P.F. 
 
 ROCKING SHAFT LEAD-OUT. 
 
 1234 6789 
 
 CRANK LEAD-OUT. 
 
 DEFLECTING BAR LEAD-OUT. 
 
 7 V 
 
 123 78 
 
 VERTICAL DEFLECTING BARS. 
 
354 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. SYMBOLS FOR RELAYS, INDICATORS AND LOCKS 
 PLATE 7 (October, 1912). 
 
 RELAYS, INDICATORS AND LOCKS. 
 
 ELEMENTS OF SYMBOLS T~T 
 
 TO BE COMBINED AS O D . C . ELECTRO MAGNET. 
 
 NECESSARY. .LL 
 
 1X1 A. C. ELECTRO MAGNET. 
 ]; ]._[ COIL ENERGIZED OR DE-ENERGIZED . 
 i..i.j i._i| NEUTRAL FRONT CONTACT - CLOSED o OPEN . 
 
 l.J. NEUTRAL BACK CONTACT - CLOSED OR OPEN . 
 POLARIZED ARMATURE - WITH CONTACTS. 
 
 3 - POSITION ARMATURE - WITH CONTACTS . 
 
 HIGH CURRENT CONTACT. 
 l..l| MAGNETIC BLOW-OUT CONTACT. 
 
 iQ. BELL ATTACHMENT. 
 
 t*"f 
 
 im DOUBLE WINDING -SPECIFY IF DIFFERENTIAL. 
 
 f-T 
 
 jfsi SLOW ACTING. 
 
 & T f, 
 
 i..i L.I Disc TVPE INDICATOR. O= Disc INVISIBLE. "Disc VISIBLE. 
 1 1^ f= 
 i..i i.i i-.l i..i SEMAPHORE TYPE INDICATOR, f 83 - 3- POSITION. 
 
 -o- 
 
 M OR Mi OR Ml WIRE WOUND ROTOR 
 
 -*> 
 
 3l-^i R i-i , STATIONARY WINDINS . IrSi.- HIGH VOLTAGE WINDING . 
 
 ELECTRIC LOCK- SHOW SEGMENTS FOR LEVER IN NORMAL 
 POSITION . 
 (SEE NEXT PAGE FOR- EXAMPLES OF COMBINATIONS.) 
 
ELECTRIC INTERLOCKING HANDBOOK 355 
 
 R. S. A. SYMBOLS FOR RELAYS, INDICATORS AND LOCKS 
 PLATE 8 (October, 1912). 
 
 RELAYS , INDICATORS AND LOCKS. 
 
 EXAMPLES OF COMBINATIONS. 
 
 FT D.C. RELAY- NEUTRAL- ENERGIZED - 
 
 1,1 ONE INDEPENDENT FRONT CONTACT CLOSED - 
 
 ONE INDEPENDENT BACK CONTACT OPEN. 
 
 & D.C. RELAY -POLARIZED -ENERGIZED - 
 
 Two COMBINATION FRONT AND BACK NEUTRAL CONTACTS - 
 * t Two POLARIZED CONTACTS CLOSED 
 
 Two POLARIZED CONTACTS OPEN. 
 
 J.L 
 
 fi. 
 
 o 
 
 -o 
 
 A 
 
 O.C. INDICATOR- SEMAPHORE Type -ENERGIZED - 
 THREE FRONT CONTACTS .. CLOSED 
 BELL ATTACHMENT . 
 
 O.C. INDICATOR -SEMAPHORE TYPE -ARM HORIZONTAL- 
 ENERGIZED - WITHOUT CONTACTS . 
 NOTE : INDICATORS (OR REPEATERS) WITHOUT CONTACTS SHOULD BE SHOWN 
 
 WITH ARMATURES TO INDICATE WHETHER ENERGIZED OR DC-ENER- 
 GIZED . 
 
 A.C.RELAY-ONE ENERGIZING CIRCUIT TYPE (SINGLE PHASE) 
 
 ENERGIZED ONE FRONT CONTACT. 
 
 A. C. RELAY- Two ENERGIZING CIRCUIT TYPE- ENERGIZED 
 WIRE WOUND ROTOR - 
 Two NEUTRAL FRONT CONTACTS . 
 
 A.C. RELAY-Two ENERGIZINS CIRCUIT TYPE - ENERBIZED 
 WIRE WOUND ROTOR - 
 Two POLARIZED CONTACTS. 
 
 A.C RELAY-Two ENERSIZING CIRCUIT TYPE -ENERGIZED' 
 STATIONARY WINDINGS - 
 ONE NEUTRAL FRONT CONTACT 
 . Two 3- POSITION CONTACTS. 
 
 t ' t 
 
 D.C. INTERLOCKED RELAY. 
 
 O.C. ELECTRIC BELL. 
 
 DESI6NATE RESISTANCE IN OHMS OF ALL D.C. RELAYS, INDICATORS AND LOCKS. 
 
356 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. SYMBOLS FOR CIRCUIT CONTROLLERS 
 PLATE 9 (October, 1912). 
 
 CIRCUIT CONTROLLERS OPERATED BY LEVERS. 
 
 Use EITHER LETTER SYSTEM OR GRAPHIC SYSTEM. 
 
 ievEBSWTH ExntcMi END POSITION AS NORMAL . 
 
 N- FULL NORMAL POSITION OF LEVER 
 B- NORMAL INDICATION POSITION . 
 
 C-GCNTRAL POSITION. 
 
 0- REVERSE INDICATION POSITION. 
 R-Fuu. REVERSE POSITION. 
 
 LEVERS WITH MIDDLE POSITION AS NORMAL. 
 N-NORMAL POSITION. 
 L-Fuu. REVERSE POSITION TO THE LEFT. 
 B -INDICATION POSITION TO THE LEFT. 
 -INDICATION POSITION TO THE RIGHT. 
 R-Fuu REVERSE POSITION TO THE RIGHT. 
 
 LETTER 
 SYMBOL. 
 
 B N D 
 
 NOTE: HEAVY HORIZONTAL LINES INDICATE PORTION or CYCLE OF LEVER THROUGH WHICH CIRCUIT is CLOSED 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 357 
 
 R. S. A. SYMBOLS FOR CIRCUIT CONTROLLERS 
 PLATE 10 (October, 1912). 
 
 CIRCUIT CONTROLLERS OPERATED BY SIGNALS. 
 
 UPPER QUADRANT. LOWER QUADRANT. 
 
 CLOSED AT ONLY. 
 
 3 -POSITION 
 SIGNALS. 
 
 60-70 OB 
 75 SIGNALS. 
 
 CLOSED AT 45 ONLY. 
 
 CLOSED AT 90 ONLY. 
 
 CLOSED TO 45 
 
 CLOSED 45 TO 90 
 
 CLOSED AT Owtx. 
 
 CLOSED IN CLEAR 
 POSITION ONLY. 
 
 
 CLOSED. 
 OPEN. 
 
 :=t=: 
 
 CIRCUIT CONTROLLER OPERATED BY LOCKING 
 SWITCH CIRCUIT CONTROLLER. MECHANISM OF A SWITCH MOVEMENT. 
 
 CLOSED. 
 OPEN. 
 
 BRIDGE CIRCUIT CONTROLLER. 
 
 POLE CHANGING CIRCUIT CONTROLLER. 
 
 SPRING HAND KEY OR PUSH BUTTON. 
 
 CIRCUIT SWITCH. 
 
358 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 R. S. A. SYMBOLS FOR CIRCUIT CONTROLLERS, RELEASES, ETC. 
 PLATE 11 (October, 1912). 
 
 MANUAL TIME RELEASE . 
 (ELECTRIC) 
 
 MANUAL TIME RELEASE, . 
 (ELECTRO -MECHAN'L.) 
 
 AUTOMATIC TIME RELEASE . 
 
 (ELECTRIC) 
 
 EMERGENCY RELEASE . 
 (ELECTRIC) 
 
 f 
 
 FLOOR PUSH, 
 
 /I 
 
 OPEN. CLOSED. 
 
 LATCH CONTACT. TRACK INSTRUMENT CONTACT. 
 
 KNIFE SWITCHES. 
 
 d) (DO O O (D 
 
 RHEOSTAT. SINGLE POLE. DOUBLE POLE. SINGLE POLE. DOUBLE POLE. 
 SINGLE THROW. DOUBLE THROW. 
 
 QUICK ACTING CIRCUIT CONTROLLERS MAY BE DISTINGUISHED BY THE LETTER "9" 
 
 sAA/V 
 
 FIXED RESISTANCE . VARIABLE RESISTANCE . 
 
 IMPEDANCE WITHOUT IMPEDANCE WITH 
 IRON CORE. IRON CORE 
 
 FUSE . 
 
 CONDENSER. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 359 
 
 R. S. A. SYMBOLS FOR BATTERIES, GENERATORS, MOTORS, ETC. 
 PLATE 12 (October, 1912). 
 
 BATTERY. 
 
 A.C.TERMINALS. 
 
 CELLS IN MULTIPLE. CELLS IN SERIES. 
 
 SPECIFY TYPE AMD NUMBER OF CELLS . "ECTi FI ER . 
 
 D DRY BATTERY. 
 6 GRAVITY 
 P POTASH 
 S STORAGE 
 
 EXAMPLES: I6P, IDS, ETC. 
 
 D.C.TERMINALS. 
 
 roooooWj 
 
 I-SECONDARY. 2-0 MORE SECONDARIES. 
 
 TRANSFORMERS. 
 
 (M) 
 
 O.C. MOTOR. 
 
 A.C. GENERATOR. 
 
 S 
 
 AMMETER . 
 
 D.C.GENERATOR. 
 
 A.C. MOTOR. 
 
 M) (G 
 
 D.C.-D.C. MOTOR-GENERATOR. A.C.-D.C. MOTOR- 
 
 sY> 
 
 VOLTMETER. 
 
 WATTMETER. TELEPHONE 
 
 SINGLE. DOUBLE. 
 
 INCANDESCENT LAMP. LIGHTNING ARRESTER. TERMINALS. 
 
 WIRES CROSS . 
 
 WIRES JOIN. 
 
 GROUND. 
 
 " COMMON " WIRE . 
 
 TRACK CIRCUIT WIRE. 
 
 OTHER THAN " COMMON" WIRE. 
 
 DIRECTION OF CURRENT. 
 

 
SECTION XVII 
 
 GENERAL DATA 
 
 COVERING THE WEIGHTS OF G. R. S. 
 INTERLOCKING APPARATUS, MAINTE- 
 NANCE TOOLS REQUIRED, BELTING, 
 PULLEYS, SWITCH-LEADS AND CROSS- 
 OVERS, TABLES OF NAILS, SCREWS, 
 NUTS, ETC., TABLES OF SPECIFIC 
 GRAVITIES, WEIGHTS AND MEASURES, 
 FAHRENHEIT AND CENTIGRADE TEM- 
 PERATURES, FRACTIONS AND DECIMAL 
 EQUIVALENTS, POWERS AND ROOTS, 
 AREAS AND CIRCUMFERENCES OF 
 CIRCLES, ETC., ETC. 
 
GENERAL DATA 
 
 SHIPPING WEIGHTS OF G. R. S. APPARATUS 
 
 Shipping 
 
 CHARGING APPARATUS pJS?' 
 
 D. C. Generator, capacity 1.25 K. W. (Page 169), . . 290 
 
 D. C. Generator, capacity 2.50 K. W., 340 
 
 D. C. Generator, capacity 3.25 K. W., 500 
 
 D. C.-D. C. Motor Generator Set, capacity 1.25 K. W. 
 
 (Page 168), 600 
 
 D. C.-D. C. Motor Generator Set, capacity 2.40 K. W., 800 
 
 D. C.-D. C. Motor Generator Set, capacity 3.25 K. W., 1050 
 
 The above weights cover the necessary starting devices 
 and field rheostats. 
 
 TRANSFORMERS 
 
 Type K, air cooled (Fig. 249), 20 
 
 Type LI, complete with oil, hanger, and cut-outs 
 
 (Fig. 247), 130 
 
 Type L2, complete with oil, hanger, and cut-outs, 175 
 
 Type L3, complete with oil, hanger, and cut-outs, 210 
 
 POWER SWITCHBOARDS 
 
 Board, 24" x 36", controlling 1 H. V. battery and 1 
 generator (Fig. 117), 210 
 
 Board, 24" x 48", controlling 1 H. V. battery, duplicate 
 sets of L. V. battery and 1 generator (Fig. 119), . . 410 
 
 Board, 48" x 48", controlling 1 H. V. battery, duplicate 
 sets of L. V. battery, 4 sets track battery, and 1 gen- 
 erator (Fig. 121), 600 
 
 OPERATING SWITCHBOARDS 
 
 1 Section Board, 12" x 36", no voltmeter (Fig. 128), . 280 
 
 2 Section Board, 24" x 36", no voltmeter, 530 
 
 3 Section Board, 36" x 36", no voltmeter, 800 
 
 1 Section Board, 12" x 48", with voltmeter, 350 
 
 Panel, 12" x 12", with voltmeter, 70 
 
 LIGHTING PANELS FOR POWER AND OPERATING BOARDS 
 
 Panel, 12" x 12", with 5 S. P. S. T. switches (Fig. 130), . 90 
 
 Panel, 12" x 18", with 10 S. P. S. T. switches (Fig. 132), . 110 
 Panel, 12" x 24", with 6 D. P. S. T. or 12 S. P. S. T. 
 
 switches, 150 
 
 Panel, 12" x 36", with 9 D. P. S. T. or 18 S. P. S. T. 
 
 switches, 190 
 
 INTERLOCKING MACHINE 
 Model 2 1 tier locking. 
 
 Per lever, 90 
 
 Per spare space, 70 
 
364 GENERAL RAILWAY SIGNAL COMPANY 
 
 Shi 
 We 
 
 Model 2 2 tier locking. Pounds' 
 
 Per lever, ................... 100 
 
 Per spare space, ................ 80 
 
 Model 2 3 tier locking (Fig. 137). 
 
 Per lever, ................... 110 
 
 Per spare space, ................ 90 
 
 Model 2 4 tier locking. 
 
 Per lever, ................... 120 
 
 Per spare space, ................ 100 
 
 Unit Type 1 tier locking. 
 
 Per lever, ...... ............. 110 
 
 Per spare space, ................ 80 
 
 Unit Type 2 tier locking. 
 
 Per lever, . . ................. 120 
 
 Per spare space, ............ *'!.".. 90 
 
 Unit Type 3 tier locking (Fig. 136). 
 
 Per lever, ................... 130 
 
 Per spare space, ................ 100 
 
 Unit Type 4 tier locking. 
 
 Per lever, ................... 150 
 
 Per spare space, ................ 120 
 
 The above weights for machines complete with levers, 
 individual polarized relays, riveted locking, and cabinet. 
 
 Complete Set of Locking Average weights per work- 
 ing lever. 
 
 1 Tier of Locking, ................ 10 
 
 2 Tiers of Locking, ................ 15 
 
 3 Tiers of Locking, ................ 20 
 
 4 Tiers of Locking, ................ 25 
 
 Separate Lever complete with polarized relay, .... 40 
 
 Lever Lock (Fig. 141) applied to machine, ..... 10 
 
 SWITCH LAYOUTS (Crank Connected) 
 
 Single Switch, Model 2 switch machine (Fig. 163), . . 1000 
 Single Switch, Model 4 switch machine (Fig. 162), . . 1500 
 Split Point Derail, Model 2 switch machine (Fig. 165), . 1000 
 
 Split Point Derail, Model 4 switch machine (Fig. 164), . 1500 
 
 (Fig. 167 
 Hayes Derail, Model 4 switch machine (Fig. 166), . . 1600 
 
 , . 
 
 Hayes Derail, Model 2 switch machine (Fig. 167), . . 1100 
 
 Wharton or Morden Derail, Model 2 switch machine 
 
 (Fig. 169), .................. 1100 
 
 Wharton or Morden Derail, Model 4 switch machine 
 
 (Fig. 168), .................. 1600 
 
 Single Slip Switch (one end), Model 2 switch machine 
 
 (Fig. 171), .................. 1000 
 
 Single Slip Switch (one end), Model 4 switch machine 
 
 (Fig. 170), .................. 1500 
 
 Double Slip Switch (one end), Model 2 switch machine 
 
 (Fig. 173), .................. 1200 
 
ELECTRIC INTERLOCKING HANDBOOK 365 
 
 Pounds 
 
 Double Slip Switch (one end), Model 4 switch machine 
 (Fig. 172), 1800 
 
 Movable Point Frog, Model 2 switch machine (Figs. 
 175, 177), 1600 
 
 Movable Point Frog, Model 4 switch machine (Figs. 
 174, 176), 2000 
 
 The above weights are for switch machines complete 
 with tie plates, throw rod, lock rod, No. 1 switch rod, rail 
 braces, and all necessary bolts, nuts, and cotters. Switch 
 connections insulated. Weights for Model 4 switch 
 machine layouts include switch circuit controller and 
 connections. Weights do not include detector bars. 
 
 Model 2 Switch Machine (Fig. 159), 500 
 
 Model 4 Switch Machine for single switch or derail 
 
 (Fig. 161), 850 
 
 Model 4 Switch Machine for movable point frog or 
 
 double slip switch (Fig. 160), 950 
 
 DETECTOR BAR LAYOUTS (Crank Connected) 
 
 1 Bar, same side for Model 2 or Model 4 switch machine, 360 
 
 1 Bar, opposite side for Model 2 or Model 4 switch 
 machine, 460 
 
 2 Bars, for Model 2 or Model 4 switch machine, . . . 770 
 1 Bar, for two Model 2 or Model 4 switch machines, . 780 
 
 The above weights for detector bar layouts are com- 
 plete with all connections and necessary bolts, nuts, etc. 
 Connections insulated. 
 
 SIGNALS RSA DIMENSIONS 
 
 Pipe Bracket Post complete, narrow deck, 3400 
 
 Pipe Bracket Post complete, wide deck, 3800 
 
 1 Arm Ground Signal complete, 22' 6" base to center 
 of arm, 1270 
 
 1 Arm Ground Signal complete, 29' 6" base to center 
 
 of arm, 1430 
 
 2 Arm Ground Signal complete, 22' 6" base to center 
 
 of lower arm, 1850 
 
 2 Arm Ground Signal complete, 28' 6" base to center 
 
 of lower arm, 2000 
 
 3 Arm Ground Signal complete, 22' 6" base to center 
 
 of lower arm, 2420 
 
 1 Arm Bracket or Bridge Signal complete, 3' 6" base 
 to center of arm, 710 
 
 1 Arm Bracket or Bridge Signal complete, 10' 6" base 
 
 to center of arm, 900 
 
 2 Arm Bracket or Bridge Signal complete, 3' 6" base 
 
 to center of lower arm, 1310 
 
366 GENERAL RAILWAY SIGNAL COMPANY 
 
 Shipping 
 Weights. 
 Pounds 
 
 2 Arm Bracket or Bridge Signal complete, 9' 6" base 
 
 to center of lower arm, 1450 
 
 3 Arm Bracket or Bridge Signal complete, 3' 6" base 
 
 to center of lower arm, 1860 
 
 The above signals complete with mechanism, ladders, 
 spectacles, blades, lamp brackets, foundation bolts, etc. 
 
 Cantilever Bracket complete, 200 
 
 Dummy Mast, 300 
 
 Fixed Arm complete, 130 
 
 Model 2 A, 110 Volt Signal Mechanism complete, with 
 
 clamp bearing (Fig. 199), 350 
 
 DWARF SIGNALS 
 
 Model 2A Dwarf Signal complete (Figs. 204, 205), . . 380 
 
 Model 2, 1 Arm Dwarf Signal complete (Fig. 207), . . 150 
 
 Model 2, 2 Arm Dwarf Signal complete (Fig. 206), . . 300 
 
 Model 3, 1 Arm Dwarf Signal complete (Fig. 208), . . 140 
 
 The above signals complete with spectacle, blade, 
 lamp bracket, foundation bolts, etc. 
 
 SWITCH CIRCUIT CONTROLLERS 
 
 Model 5, Form A Switch Circuit Controller (Fig. 186), 60 
 
 Model 3, Switch Circuit Controller, 4 circuits (Fig. 185), 40 
 
 Model 3, Switch Circuit Controller, 8 circuits, 60 
 
 Add for Short Operating Rod, 15 
 
 Add for Long Operating Rod, 25 
 
 RELAYS AND INDICATORS 
 
 Model 9, D. C. Relay, 4-way (Figs. 228, 229), .... 30 
 
 Model 9, D. C. Relay, 8-way, 35 
 
 Model 1, D. C. Relay, not inclosed, 30 
 
 Model 1, D. C. Relay, inclosed, 35 
 
 Model 9, Tower Indicator, 4-way (Fig. 230), 30 
 
 Model 9, Tower Indicator, 8-way 40 
 
 Model 9, Indicator Group, with 4-way indicators 
 
 (Fig. 83), per indicator, 35 
 
 Model 9, Indicator, Group with 8-way indicators, 
 
 per indicator, 45 
 
 Model 2, Form A Polyphase Relay, 4-way (Fig. 235), 65 
 
 Model 2, Form A Polyphase Relay, 6-way, 70 
 
 Model 2, Model 3, or Model Z, Form B Relay, 4-way 
 
 (Fig. 232), 40 
 
 Model 2, Model 3, or Model Z, Form B Relay, 6-way, 45 
 Model 2, Model 3, or Model Z, Form B Indicating 
 
 Relay, 4-way (Fig. 234), 50 
 
 Model 2, Model 3, or Model Z, Form B Indicating < 
 
 Relay, 6-way, , . , 55 
 
ELECTRIC INTERLOCKING HANDBOOK 367 
 
 Shipping 
 Weights. 
 Pounds 
 
 Model 2, Model 3, or Model Z, Form B Tower Indi- 
 cator (Fig. 233), 35 
 
 RELAY BOXES 
 
 1-way Iron Box for D. C. relays, 120 
 
 2-way Iron Box for D. C. relays (Fig. 242) 160 
 
 3-way Iron Box for D. C. relays, 250 
 
 4-way Iron Box for D. C. relays, 225 
 
 1-way Wood Box for D. C. relays, 25 
 
 2-way Wood Box for D. C. relays (Fig. 243), .... 35 
 
 3-way Wood Box for D. C. relays 50 
 
 1-way Wood Box for Model 2 Form A relays, 40 
 
 2-way Wood Box for Model 2 Form A relays (Fig. 241), 55 
 
 3-way Wood Box for Model 2 Form A relays, 75 
 
 The above boxes complete with terminal board and 
 U bolts or bracket for mounting on stub pole. 
 
 Add for mounting on signal mast, 20 
 
 Posts for mounting relay box on foundation, .... 40 
 
 Post for mounting relay box on battery chute, .... 70 
 
 BATTERY CHUTES (Page 292) 
 
 6-ft. Single Battery Chute, complete with elevator, . . 260 
 
 7-ft. Single Battery Chute, complete with elevator, 
 8-ft. Single Battery Chute, complete with elevator, . 
 9-ft. Single Battery Chute, complete with elevator, . 
 7-ft. Double Battery Chute, complete with elevator, 
 9-ft. Double Battery Chute, complete with elevator, 
 
 290 
 350 
 390 
 520 
 650 
 
 IMPEDANCE BONDS 
 
 Size 1, Form C Bond (Fig. 91), per single bond, ... 610 
 Size 2, Form B Bond (Fig. 92), per single bond, ... 420 
 Size 3, Form A Bond (Fig. 92), per single bond, . . . 250 
 
 TRUNKING, STAKES, AND JUNCTION BOXES (Figs. 270, 271) 
 
 3" x 4" Trunking with Capping, pine, per 1,000 lineal 
 feet, 5300 
 
 3" x 4" Trunking with Capping, cedar, per 1,000 lineal 
 feet, 3000 
 
 Built-Up Trunking, pine, per 1,000 feet, B. M 3350 
 
 Built-Up Trunking, cedar, per 1,000 feet, B. M., . 
 Oak Stakes, 3" x V x 3' 0" (square end), .... 
 Oak Stakes, 3" x 4" x 4' 0" (square end); .... 
 Cedar Stakes, 4" diameter x 3' 0" (pointed), . . . 
 
 Cedar Stakes, 4" diameter x 3' 6" (pointed), 10 
 
 Junction Box, inside dimensions, 15W x 15W x 11", . 40 
 Junction Box, inside dimensions, 16" x 16" x 20", . . 60 
 
 1900 
 10 
 15 
 10 
 
368 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
ELECTRIC INTERIX)CKING HANDBOOK 369 
 
 COMPLETE LIST OF MAINTENANCE TOOLS 
 REQUIRED AT ELECTRIC INTER- 
 LOCKING PLANTS 
 
 BLACKSMITH TOOLS 
 1 Anvil. 
 1 Forge. 
 
 1 Set of tools, including 10 pound hammer, cold cutter and 
 %" punch. 
 
 CARPENTERS TOOLS 
 1 18" square. 
 1 Jack plane. 
 1 Brace with set of bits. 
 1 1 %e" single lip car bit 14" long. 
 1 %* wood chisel. 
 1 26" No. 9 hand saw. 
 1 Hand axe. 
 1 Adze. 
 1 Claw hammer. 
 
 ELECTRICAL TOOLS 
 
 1 Soldering furnace-pot and two ladles. 
 
 1 Small soldering copper. 
 
 2 Screw drivers, 6" and 10". 
 1 Aligator pliers, 8". 
 
 1 Side-cutting pliers, 7". 
 1 Contact adjuster. 
 
 1 Binding-post wrench. 
 
 2 Socket wrenches for 1 A" hexagon nut. 
 1 Wrench for signal circuit breaker. 
 
 1 Crank for switch motor. 
 
 1 Hydromotor. 
 
 1 Portable volt-ammeter. 
 
 1 Solid wrench for %" hexagon nuts. 
 
 LINE CIRCUIT TOOLS 
 
 1 Belt with safety. 
 1 Pair 16" climbers. 
 
 1 "Come along" with blocks. 
 
 2 Connectors. 
 
 PIPE TOOLS 
 (For pipe connected detector bars.) 
 
 1 Stilson wrench. 
 
 2 Pipe rivet punches. 
 1 Pipe cutter. 
 
 1 Stock with 1" right-hand dies. 
 
 SWITCH FITTING TOOLS 
 
 1 Machinist hammer. 
 1 Center punch. 
 
370 GENERAL RAILWAY SIGNAL COMPANY 
 
 2 Cold chisels. 
 
 1 12" tommy bar bent on both ends. 
 
 1 20" tommy bar bent on chisel end only. 
 
 1 Packer ratchet with His" and 13 /i 6 " drill. 
 
 1 "Old man" for drilling rail. 
 
 2 Switch-adjusting wrenches. 
 
 3 Two-man "T " socket wrenches for %" square and hexagon 
 
 nut, and %" lag screws. 
 2 "T" socket wrenches for %" and W lag screws. 
 
 4 Solid "S" wrenches for %" and %" bolts with square or 
 
 hexagon nut. 
 1 Solid wrench for detector bar clips. 
 
 1 14" Monkey wrench. 
 
 2 Reamers, %" and %". 
 1 14" Stilson wrench. 
 
 1 6" Westcott wrench. 
 
 4 Files: one-14" flat bastard, one-10" flat smooth, one-12" 
 
 half-round bastard, one-12" round. 
 4 Files: two-6" rat tail, two saw files. 
 
 TRACK TOOLS 
 1 Spike maul. 
 1 Spike puller. 
 1 Claw bar. 
 1 Track wrench. 
 1 Track shovel. 
 1 Barn broom. 
 1 Railroad pick. 
 
 TRACK-CIRCUIT TOOLS 
 
 1 Bonding drill with twelve % 2 " twist drills. 
 
 2 Channel pins punches. 
 
 1 Channel pin set (slotted). 
 
 MISCELLANEOUS 
 
 1 Workbench with combination vise. 
 
 1 Drill press with drills. 
 
 1 Set taps and dies with stock W to 1". 
 
 1 Breast drill with set of drills W to %" by 32nds. 
 
 1 Bench emery wheel. 
 
 1 Hack saw, 12 blades. 
 
 1 Large spout oiler (1 quart). 
 
 1 9" spout oiler (1 pint). 
 
 1 6" spout oiler 04 pint). 
 
 2 Water pails. 
 
 1 Canvas tool bag. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 371 
 
 MODEL 1 FORM A LIGHTNING ARRESTER 
 
 Fig. 276 illustrates the G. R. S. Co.'s Model 1 Form A light- 
 ning arrester, designed for use on signal, telegraph, telephone, 
 crossing alarm circuits, etc. 
 
 The arrester has a high efficiency, i. e., a high reactance 
 and negligible ohmic resistance. This high reactance is 
 maintained under all conditions of frequency and current 
 owing to the fact that no iron is used in the core of the react- 
 ance coil. 
 
 The arrester is small ( 1 %6*x4%*x4%?) and may be assem- 
 bled in banks on one inch 
 centers. Connectors between 
 the ground plates are provided, 
 which form a buss bar of ample 
 carrying capacity, thereby mak- 
 ing requisite but one ground 
 connection for any number of 
 arresters. Multiple point dis- 
 charge plates are provided 
 instead of the single point type 
 or one having a circular sur- 
 face. The parts used in the 
 arrester construction are few, 
 none of them being delicate 
 or easily broken. The con- 
 nections are all in front, thus 
 allowing it to be easily installed 
 pr^ x / ^TH and inspected. 
 
 I! i. . L_! ill The Model 1 Form A uses 
 
 the same component parts as 
 the Model 1 arrester, thou- 
 sands of which are at the 
 present time in service, many 
 them showing evidence of 
 having taken care of heavy 
 discharges without injury re- 
 sulting to the arrester or the 
 protected apparatus. 
 
 The arresters should be grounded through two No. 8 
 B. & S. gauge copper wires, insulated above the ground. 
 The wires should be wrapped around and soldered to a gal- 
 vanized ground rod, not less than one inch in diameter, driven 
 eight feet into the ground. 
 
 FIQ. 276. MODEL 1 FORM A 
 LIGHTNINO ARRESTERS 
 
372 GENERAL RAILWAY SIGNAL COMPANY 
 
 to VOLTS LIMITING RESISTANCE IS OHMS 
 
 I AMPERE RANGE 
 
 r 
 
 ^J*/W (t$^ 
 
 APPROXIMATELY K> FECT- 
 FIG. 277. CIRCUIT FOR TESTING RESISTANCE OP GROUNDS 
 
 NOTE. Several readings should be made and the average taken. The 
 resistance should then be computed by dividing the voltage reading by the 
 current. 
 
 The limiting resistance used in making the test may merely be a unit of 
 such resistance as to protect the instruments, it being recommended, how- 
 ever, that- a variable resistance be used if available. If a voltage higher 
 than that indicated is used, the range of the voltmeter and the resistance 
 unit employed will have to be increased accordingly. 
 
 
 
 PULLEYS AND GEARS 
 
 When it is desired to secure single reduction or increase of 
 speed by means of belting, the speed at which each shaft 
 should run and the diameter of one pulley being known, 
 multiply the diameter of the known pulley by the speed in 
 revolutions per minute of its shaft and divide this product by 
 the speed in revolutions per minute of the second shaft; the 
 result is the desired diameter of the second pulley. 
 
 When the diameter of both pulleys and the speed of one 
 shaft is known, multiply the speed of that shaft by the diame- 
 ter of its pulley and divide this product by the diameter of 
 the pulley on the other shaft; the result is the speed at which 
 the second shaft will be run. 
 Let D = diameter of driving pulley. 
 d = diameter of driven pulley. 
 
 S = number of revolutions per minute of driving shaft, 
 s = number of revolutions per minute of driven shaft. 
 
 Then the above may be expressed by the following formula : 
 
 DxS 
 
 Where a counter-shaft is used, to obtain either size or speed 
 of the main driving or driven pulley, calculate as above, 
 between the known end of the transmission and the counter- 
 shaft and then repeat this calculation between the counter- 
 shaft and tne unknown end. 
 
 Gears in mesh transmit speeds in proportion to the number 
 of teeth they contain. Count the number of teeth in the gear- 
 ing and substitute this quantity for the diameter of the pulleys 
 mentioned above, in order to obtain the number of teeth to be 
 cut in unknown gear or speed of the second shaft. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 373 
 
 WIDTHS OF BELTING PER HORSE POWER 
 
 A rule commonly used for determining the width of belting 
 is that "single" belt will transmit 1 H. P. for each inch in 
 width at a speed of 1,000 feet per minute. If the speed is 
 greater or less the power transmitted is correspondingly 
 increased or decreased. 
 
 The rule may be stated as follows : 
 TT p _w x d xrpm_wv 
 3820 ~1000 
 In which w = width of belt in inches. 
 
 d = diameter of pulley in inches. 
 v = velocity of belt in feet per minute. 
 rpm= revolutions per minute. 
 
 This is based on a working tension of 30 pounds per inch of 
 width of belt. Many writers give as a safe practice for single 
 belts in good condition a working tension of 45 pounds per 
 inch of width, which formula gives a permissible increase in 
 transmitted horse power of 50 per cent, over the formula 
 TT T> _wxdxrpm 
 
 H '^ 3820~ 
 
 For "double" belts of average thickness, the transmitting 
 efficiency is considered as 10 to 7 compared to the single belt- 
 ing discussed above. 
 
 These formulas are based on the supposition that the arc of 
 contact between belt and pulley is 180 degrees. For other arcs 
 the transmitting power is approximately proportional to the 
 ratio of the degrees of arc of contact to 180 degrees. 
 
 TABLE FOR DETERMINING WIDTH OF BELTING 
 
 Speed in 
 Feet per 
 Minute 
 
 WIDTH OP BELT IN INCHES 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 H. P. 
 
 H. P. 
 
 H. P. 
 
 H. P. 
 
 H. P. 
 
 500 
 
 1 
 
 1.5 
 
 2 
 
 2.5 
 
 3 
 
 1000 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 1500 
 
 3 
 
 4.5 
 
 6 
 
 7.5 
 
 9 
 
 2000 
 
 4 
 
 6 
 
 8 
 
 10 
 
 12 
 
 2500 
 
 5 
 
 7.5 
 
 10 
 
 12.5 
 
 15 
 
 3000 
 
 6 
 
 9 
 
 12 
 
 15 
 
 18 
 
 3500 
 
 7 
 
 10.5 
 
 14 
 
 17.5 
 
 21 
 
 4000 
 
 8 
 
 12 
 
 16 
 
 20 
 
 24 
 
 4500 
 
 9 
 
 13.5 
 
 18 
 
 22.5 
 
 27 
 
 5000 
 
 10 
 
 15 
 
 20 
 
 25 
 
 30 
 
 NOTE. Based on the formula H. P.= 
 
 In running, the upper side of the belt should sag downward, 
 the belt will then be in contact with more than half the cir- 
 
374 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 cumference of the pulley, and the power increased in the pro- 
 portion referred to in the preceding paragraph. Best results 
 are secured by running belt just tight enough to prevent 
 slipping at normal load. 
 
 PAINTING 
 EXTRACTS FROM R. S. A. SPECIFICATIONS FOR ELECTRIC 
 
 INTERLOCKING (1910) 
 800. PAINT 
 
 Field work. 
 
 (6) Surfaces covered with rust, grease, dirt, or other 
 foreign substances, shall be thoroughly cleaned before 
 paint or oil is applied. 
 
 (c) Paint shall not be applied to outside surfaces in 
 freezing weather, nor to wet surfaces, nor until previous 
 coating has thoroughly dried. 
 
 (d) Finishing coats shall not be applied until after the 
 expiration of forty-eight (48) hours after the previous 
 coating has been applied. 
 
 (e) Paints mixed on the ground shall be applied within 
 three (3) hours after the pigment and oil are mixed. 
 
 (/) Priming coats shall be applied as soon as is con- 
 sistent with the progress of the work. 
 
 (gf) Second coat shall be applied in sufficient time for 
 the third coat to be applied and dry when the installation 
 is completed. 
 
 810. IRON WORK 
 
 (a) Iron work (except machine, tie plates, and iron 
 foundation piers) not galvanized shall be painted one (1) 
 coat of red lead and raw linseed oil and two (2) finishing 
 coats. 
 
 AMOUNT OF PAINT REQUIRED PER 1000 FEET OF 
 TRUNKING AND CAPPING 
 
 Size of Trunking 
 Inches 
 
 Size of Capping 
 Inches 
 
 Gallons (two coats) 
 
 2x 3 
 
 1x3 
 
 4 
 
 3x 4 
 
 iy 4 x 4 
 
 5V 2 
 
 4x7 
 
 1V2X 7 
 
 9 
 
 4x 10 
 
 2 xlO 
 
 11 
 
 NOTE. The covering capacity of paint depends largely on the condition 
 of the surface being finished, the handling of the goods by the painter, and 
 the temperature of the surface painted. The above figures are based on 
 average working conditions. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 375 
 
 RAIL SECTIONS 
 
 A. R. A. RAILS TYPE "A" 
 
 Weight 
 
 
 
 
 
 
 
 
 per 
 
 A 
 
 B 
 
 c 
 
 D 
 
 E 
 
 F 
 
 G 
 
 Yard 
 
 
 
 
 
 
 
 
 Lbs. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 60 
 
 4y 2 
 
 22% 4 
 
 "Ho 
 
 ! 15 /64 
 
 2V4 
 
 15 /32 
 
 4 
 
 70 
 
 4 8 /4 
 
 2y 2 
 
 2 %2 
 
 1!%2 
 
 2% 
 
 y 2 
 
 4y 4 
 
 80 
 
 5Vs 
 
 22% 2 
 
 ^32 
 
 1% 
 
 2V 2 
 
 8 %4 
 
 4% 
 
 90 
 
 5% 
 
 3% 2 
 
 1 
 
 l 15 /32 
 
 2%e 
 
 %e 
 
 5y 8 
 
 100 
 
 6 
 
 3% 
 
 IVie 
 
 1%6 
 
 2/4 
 
 % 
 
 5y 2 
 
 A. R. A. RAILS TYPE "B" 
 
 Weight ; 
 per 
 Yard 
 
 Lbs. 
 
 In. 
 
 60 
 70 
 80 
 90 
 100 
 
 In. 
 
 B %4 
 
 In. 
 
 In. 
 
 2% 
 
 l 15 /3 2 
 
 85 /04 
 
 %e 
 
 In. 
 
 4%4 
 
 5%4 
 
 A. S. C. E. RAILS 
 
 Weight 
 
 
 
 
 
 
 
 
 per 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 Yard 
 
 
 
 
 
 
 
 
 Lbs. 
 
 In. 
 
 In. 
 
 In. 
 
 In. 
 
 *In. 
 
 In. 
 
 In. 
 
 55 
 
 4He 
 
 2i%* 
 
 28/32 
 
 1^64 
 
 2y 4 
 
 15 /8 2 
 
 4%o 
 
 60 
 
 4V 4 
 
 2"/64 
 
 *%4 
 
 l%a 
 
 2% 
 
 8y 6 4 
 
 4y 4 
 
 65 
 
 4%6 
 
 2% 
 
 2 %3 
 
 1%2 
 
 218/82 
 
 y 2 
 
 4%6 
 
 70 
 
 4% 
 
 2i% 2 
 
 18 Ao 
 
 1^3 
 
 2^6 
 
 8 %4 
 
 4% 
 
 75 
 
 4i%o 
 
 2%4 
 
 2 %2 
 
 1 2 %4 
 
 2i% 2 
 
 1%2 
 
 4i3Ae 
 
 80 
 
 5 
 
 2% 
 
 % 
 
 1% 
 
 2y 2 
 
 8 %4 
 
 5 
 
 85 
 
 5%6 
 
 28/4 
 
 57 /64 
 
 1 8 %4 
 
 2%o 
 
 %e 
 
 5%6 
 
 90 
 
 5% 
 
 25%4 
 
 5 %4 
 
 l le /32 
 
 2% 
 
 %6 
 
 58/8 
 
 95 
 
 5%a 
 
 2%4 
 
 15 /ie 
 
 l*Vfl4 
 
 2iHe 
 
 %0 
 
 5%o 
 
 100 
 
 58/4 
 
 3%4 
 
 8 %2 
 
 1*%4 
 
 2% 
 
 %e 
 
 5% 
 
 110 
 
 ey 8 
 
 3iy 82 
 
 1 
 
 125/ 82 
 
 2% 
 
 8 %4 
 
 6% 
 
376 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TABLE OF TURNOUTS FROM STRAIGHT TRACK 
 GAUGE, 4 FEET, 8^2 INCHES. THROW OF SWITCH, 5 INCHES 
 
 FIG. 281 
 
 Frog 
 Num- 
 ber 
 
 Frog 
 Angle 
 FPE 
 
 Length 
 Point 
 of Frog 
 to Toe 
 PD 
 
 Length 
 Point 
 of Frog 
 to Heel 
 PE 
 
 Length 
 of 
 Switch 
 Rail 
 AC 
 
 Switch 
 Angle 
 BAC = 
 TOG 
 
 Radius 
 of 
 Center 
 Line 
 OC-i ga 
 
 Degree 
 of 
 Lead 
 Curve 
 
 Lead-Dist. 
 Actual 
 Point of 
 Switch 
 Rail to 
 Actual 
 Point of 
 Frog AB 
 
 in 
 
 t 
 
 S 
 
 
 
 ill 
 
 e 
 
 ? 3 
 Q 3 
 
 l 
 
 fc 
 
 6 
 
 9-31-38 
 
 4- 
 
 7- 
 
 11-0 
 
 2-36-19 
 
 265.39 
 
 21-43-04 
 
 47.98 
 
 7 
 
 8-10-16 
 
 4- 5 
 
 8- 1 
 
 16-6 
 
 1-44-11 
 
 362.08 
 
 15-52-29 
 
 62.10 
 
 8 
 
 7-09-10 
 
 4- 9 
 
 8- 9 
 
 16-6 
 
 1-44-11 
 
 487.48 
 
 11-46-27 
 
 67.98 
 
 9 
 
 6-21-35 
 
 6- 
 
 10- 
 
 16-6 
 
 1-44-11 
 
 605.18 
 
 9-28-42 
 
 72.28 
 
 9V 2 
 
 6-01-32 
 
 6- 
 
 10- 
 
 16-6 
 
 1-44-11 
 
 695.45 
 
 8-14-45 
 
 75.71 
 
 10 
 
 5-43-29 
 
 6- 
 
 10- 6 
 
 16-6 
 
 1-44-11 
 
 790.25 
 
 7-15-18 
 
 77.93 
 
 11 
 
 5-12-18 
 
 6- 
 
 11- 6 
 
 22-0 
 
 1-18- 8 
 
 922.65 
 
 6-12-47 
 
 94.31 
 
 12 
 
 4-46-19 
 
 6- 5 
 
 12- 1 
 
 22-0 
 
 1-18- 8 
 
 1098.73 
 
 5-12-59 
 
 100.80 
 
 15 
 
 3-49-06 
 
 7- 8 
 
 14-10 
 
 33-0 
 
 0-52- 5 
 
 1744.38 
 
 3-17-01 
 
 133.28 
 
 16 
 
 3-34-47 
 
 8- 
 
 16- 
 
 33-0 
 
 0-52- 5 
 
 1993.24 
 
 2-52-59 
 
 137.57 
 
 18 
 
 3-10-56 
 
 8-10 
 
 17- 8 
 
 33-0 
 
 0-52- 5 
 
 2546.31 
 
 2-14-31 
 
 146.51 
 
 20 
 
 2-51-51 
 
 9- 8 
 
 19- 4 
 
 33-0 
 
 0-52- 5 
 
 3257.26 
 
 1-45-32 
 
 157.42 
 
 24 
 
 2-23-13 
 
 11- 4 
 
 23- 2 
 
 33-0 
 
 0-52- 5 
 
 4886.16 
 
 1-10-21 
 
 177.22 
 
 Above from table by American Railway Engineering Association. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 377 
 
 TABLE OF CROSSOVERS 
 GAUGE, 4 FEET, 8% INCHES. THROW OF SWITCH, 5 INCHES 
 
 lead >je K ->j< Lead > 
 
 
 T" ' "^ 1 ' 
 
 
 Track Centers *""* ^^^"^"l 1 ** 11 *-**. 
 
 
 FIG. 282 
 
 
 
 DISTANCE (A) BETWEEN FROG POINTS FOR TRACK 
 
 Fro 
 
 LEAD 
 
 CENTERS BELOW 
 
 Number 
 
 
 11' 
 
 12' 
 
 13' 
 
 14' 
 
 15' 
 
 16' 
 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 6 
 
 47.98 
 
 9.5 
 
 15.5 
 
 21.5 
 
 27.5 
 
 33.5 
 
 39.5 
 
 7 
 
 62.10 
 
 11.1 
 
 18.1 
 
 25.1 
 
 32.1 
 
 39.1 
 
 46.1 
 
 8 
 
 67.98 
 
 12.7 
 
 20.7 
 
 28.7 
 
 36.7 
 
 44.7 
 
 52.7 
 
 9 
 
 72.28 
 
 14.2 
 
 23.2 
 
 32.2 
 
 41.2 
 
 50.2 
 
 59.2 
 
 m 
 
 75.71 
 
 15.0 
 
 24.5 
 
 34.0 
 
 43.5 
 
 53.0 
 
 62.5 
 
 10 
 
 77.93 
 
 15.8 
 
 25.8 
 
 35.8 
 
 45.8 
 
 55.8 
 
 65.8 
 
 11 
 
 94.31 
 
 17.4 
 
 28.4 
 
 39.4 
 
 50.4 
 
 61.4 
 
 72.4 
 
 12 
 
 100.80 
 
 19.0 
 
 31.0 
 
 43.0 
 
 55.0 
 
 67.0 
 
 79.0 
 
 15 
 
 133.28 
 
 23.8 
 
 38.8 
 
 53.8 
 
 68.8 
 
 83.8 
 
 98.8 
 
 16 
 
 137.57 
 
 25.3 
 
 41.3 
 
 57.3 
 
 73.3 
 
 89.3 
 
 105.3 
 
 18 
 
 146.51 
 
 28.4 
 
 46.4 
 
 64.4 
 
 82.4 
 
 100.4 
 
 118.4 
 
 20 
 
 157.42 
 
 31.6 
 
 51.6 
 
 71.6 
 
 91.6 
 
 111.6 
 
 131.6 
 
 24 
 
 177.22 
 
 38.0 
 
 62.0 
 
 86.0 
 
 110.0 
 
 134.0 
 
 158.0 
 
 
 TOTAL LENGTH OF CROSSOVER FOR TRACK CENTERS BELOW 
 
 Frog 
 Number 
 
 11' 
 
 12' 
 
 13' 
 
 14' 
 
 15' 
 
 16' 
 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 Feet 
 
 6 
 
 105.5 
 
 111.5 
 
 117.5 
 
 123.5 
 
 129.5 
 
 135.5 
 
 7 
 
 135.3 
 
 142.3 
 
 149.3 
 
 156.3 
 
 163.3 
 
 170.3 
 
 8 
 
 148.7 
 
 156.7 
 
 164.7 
 
 172.7 
 
 180.7 
 
 188.7 
 
 9 
 
 158.8 
 
 167.8 
 
 176.8 
 
 185.8 
 
 194.8 
 
 203.8 
 
 m 
 
 166.4 
 
 175.9 
 
 185.4 
 
 194.9 
 
 204.4 
 
 213.9 
 
 10 
 
 171.7 
 
 181.7 
 
 191.7 
 
 201.7 
 
 211.7 
 
 221.7 
 
 11 
 
 206.0 
 
 217.0 
 
 228.0 
 
 239.0 
 
 250.0 
 
 261.0 
 
 12 
 
 220.6 
 
 232.6 
 
 244.6 
 
 256.6 
 
 268.6 
 
 280.6 
 
 15 
 
 290.4 
 
 305.4 
 
 320.4 
 
 335.4 
 
 350.4 
 
 365.4 
 
 16 
 
 300.4 
 
 316.4 
 
 332.4 
 
 348.4 
 
 364.4 
 
 380.4 
 
 18 
 
 321.4 
 
 339.4 
 
 357.4 
 
 375.4 
 
 393.4 
 
 411.4 
 
 20 
 
 346.4 
 
 366.4 
 
 386.4 
 
 406.4 
 
 426.4 
 
 446.4 
 
 24 
 
 392.4 
 
 416.4 
 
 440.4 
 
 464.4 
 
 488.4 
 
 512.4 
 
 NOTE. Distance (A) between frog points based on formula 
 Distance = (track centers 2 x gauge) x frog number. 
 
378 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Per Track 
 
 BOND WIRES AND CHANNEL PINS 
 
 Diagram below gives the actual number of bond 
 fires and channel pins required for bonding 
 ingle track road (2 rails) for distances up to 
 ,000 feet. To this should be added 25 bond 
 fires and 50 channel pins for each switch, and to 
 tie total 5 per cent, added to cover loss. 
 
 Per TracK 
 
 704 I4QB 
 640 1230 
 
 K - ' i 
 
 s v 
 
 2 C o- v 
 gS coc t 
 
 <650 825 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 | 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 j 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 
 1500 750 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 y 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 f 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 i 
 
 
 f 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 y 
 
 
 1350 675 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 f 
 
 
 A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 
 
 I m . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 
 y 
 
 
 
 
 1200 600 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 f, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 y 
 
 
 A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 ^ 
 
 
 
 
 
 f 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 
 f 
 
 
 
 
 
 
 
 (050 525 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 , 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 sT 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 
 f 
 
 < 
 
 
 
 
 
 
 
 
 900 450 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 t 
 
 \ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 J 
 
 >s 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 V 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 , 
 
 
 i 
 
 
 
 
 
 
 
 
 
 
 
 
 750 375 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 600 300 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 f 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 t 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 450 225 
 
 
 
 
 
 
 
 
 y 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 t 
 
 y" 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 y 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 300 150 
 
 
 
 
 
 
 v 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 (A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 I 
 
 x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 JJ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 150 75 
 
 
 
 I 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1000 2000 3000 4000 5000 
 5 
 
 6000 Ft of Ttecl 
 80 
 
 FIG. 283 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 379 
 
 TWIST DRILL AND STEEL WIRE GAUGE 
 
 No. 
 
 Size 
 
 No. 
 
 Size 
 
 No. 
 
 Size 
 
 No. 
 
 Size 
 
 No. 
 
 Size 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 1 
 
 .2280 
 
 13 
 
 .1850 
 
 25 
 
 .1495 
 
 37 
 
 .1040 
 
 49 
 
 .0730 
 
 2 
 
 .2210 
 
 14 
 
 .1820 
 
 26 
 
 .1470 
 
 38 
 
 .1015 
 
 50 
 
 .0700 
 
 3 
 
 .2130 
 
 15 
 
 .1800 
 
 27 
 
 .1440 
 
 39 
 
 .0995 
 
 51 
 
 .0670 
 
 4 
 
 .2090 
 
 16 
 
 .1770 
 
 28 
 
 .1405 
 
 40 
 
 .0980 
 
 52 
 
 .0635 
 
 5 
 
 .2055 
 
 17 
 
 .1730 
 
 29 
 
 .1360 
 
 41 
 
 .0960 
 
 53 
 
 .0595 
 
 6 
 
 .2040 
 
 18 
 
 .1695 
 
 30 
 
 .1285 
 
 42 
 
 .0935 
 
 54 
 
 .0550 
 
 7 
 
 .2010 
 
 19 
 
 .1660 
 
 31 
 
 .1200 
 
 43 
 
 .0890 
 
 55 
 
 .0520 
 
 8 
 
 .1990 
 
 20 
 
 .1610 
 
 32 
 
 .1160 
 
 44 
 
 .0860 
 
 56 
 
 .0465 
 
 9 
 
 .1960 
 
 21 
 
 .1590 
 
 33 
 
 .1130 
 
 45 
 
 .0820 
 
 57 
 
 .0430 
 
 10 
 
 .1935 
 
 22 
 
 .1570 
 
 34 
 
 .1110 
 
 46 
 
 .0810 
 
 58 
 
 .0420 
 
 11 
 
 .1910 
 
 23 
 
 .1540 
 
 35 
 
 .1100 
 
 47 
 
 .0785 
 
 59 
 
 .0410 
 
 12 
 
 .1890 
 
 24 
 
 .1520 
 
 36 
 
 .1065 
 
 48 
 
 .0760 
 
 60 
 
 .0400 
 
 Reprinted by permission from Kent's "Mechanical Engineers' Pocket Book." 
 
 STUBS' STEEL WIRE GAUGE 
 
 "Mr* 
 
 Size 
 
 "Mr* 
 
 Size 
 
 *Wr 
 
 Size 
 
 *w/\ 
 
 Size 
 
 TVT/\ 
 
 Size 
 
 -NO. 
 
 Inch 
 
 JNO. 
 
 Inch 
 
 INO. 
 
 Inch 
 
 INO. 
 
 Inch 
 
 i\O. 
 
 Inch 
 
 Z 
 
 .413 
 
 D 
 
 .246 
 
 19 
 
 .164 
 
 41 
 
 .095 
 
 63 
 
 .036 
 
 Y 
 
 .404 
 
 C 
 
 .242 
 
 20 
 
 .161 
 
 42 
 
 .092 
 
 64 
 
 .035 
 
 X 
 
 .397 
 
 B 
 
 .238 
 
 21 
 
 .157 
 
 43 
 
 .088 
 
 65 
 
 .033 
 
 w 
 
 .386 
 
 A 
 
 .234 
 
 22 
 
 .155 
 
 44 
 
 .085 
 
 66 
 
 .032 
 
 V 
 
 .377 
 
 1 
 
 .227 
 
 23 
 
 .153" 
 
 45 
 
 .081 
 
 67 
 
 .031 
 
 u 
 
 .368 
 
 2 
 
 .219 
 
 24 
 
 .151 
 
 46 
 
 .079 
 
 68 
 
 .030 
 
 T 
 
 .358 
 
 3 
 
 .212 
 
 25 
 
 .148 
 
 47 
 
 .077 
 
 69 
 
 .029 
 
 s 
 
 .348 
 
 4 
 
 .207 
 
 26 
 
 .146 
 
 48 
 
 .075 
 
 70 
 
 .027 
 
 R 
 
 .339 
 
 5 
 
 .204 
 
 27 
 
 .143 
 
 49 
 
 .072 
 
 71 
 
 .026 
 
 Q 
 
 .332 
 
 6 
 
 .201 
 
 28 
 
 .139 
 
 50 
 
 .069 
 
 72 
 
 .024 
 
 p 
 
 .323 
 
 7 
 
 .199 
 
 29 
 
 .134 
 
 51 
 
 .066 
 
 73 
 
 .023 
 
 O 
 
 .316 
 
 8 
 
 .197 
 
 30 
 
 .127 
 
 52 
 
 .063 
 
 74 
 
 .022 
 
 N 
 
 .302 
 
 9 
 
 .194 
 
 31 
 
 .120 
 
 53 
 
 .058 
 
 75 
 
 .020 
 
 M 
 
 .295 
 
 10 
 
 .191 
 
 32 
 
 .115 
 
 54 
 
 .055 
 
 76 
 
 .018 
 
 L 
 
 .290 
 
 11 
 
 .188 
 
 33 
 
 .112 
 
 55 
 
 .050 
 
 77 
 
 .016 
 
 K 
 
 .281 
 
 12 
 
 .185 
 
 34 
 
 .110 
 
 56 
 
 .045 
 
 78 
 
 .015 
 
 J 
 
 .277 
 
 13 
 
 .182 
 
 35 
 
 .108 
 
 57 
 
 .042 
 
 79 
 
 .014 
 
 I 
 
 .272 
 
 14 
 
 .180 
 
 36 
 
 .106 
 
 58 
 
 .041 
 
 80 
 
 .013 
 
 H 
 
 .266 
 
 15 
 
 .178 
 
 37 
 
 .103 
 
 59 
 
 .040 
 
 
 
 G 
 
 .261 
 
 16 
 
 .175 
 
 38 
 
 .101 
 
 60 
 
 .039 
 
 
 
 F 
 
 .257 
 
 17 
 
 .172 
 
 39 
 
 .099 
 
 61 
 
 .038 
 
 
 
 E 
 
 .250 
 
 18 
 
 .168 
 
 40 
 
 .097 
 
 62 
 
 .037 
 
 
 
 The Stubs' Steel Wire Gauge is used in measuring drawn steel wire or 
 drill rods of Stubs' make, aud is also used by many makers of American 
 drill rods. 
 
 Reprinted by permission from Kent's "Mechanical Engineers' Pocket Book." 
 
380 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 STANDARD SCREW THREADS, NUTS, BOLT AND LAG HEADS 
 U. S. STANDARD 
 
 Dlam. of 
 Screw 
 
 Inch 
 
 Threads 
 per Inch 
 
 Dlam. of 
 Core 
 
 Inch 
 
 Width of 
 Flat 
 
 Inch 
 
 Outside 
 Dlam. 
 Hex. Head 
 Inch 
 
 Inside 
 Diam. 
 Hex. or 
 Sq.Head 
 Inch 
 
 Diago- 
 nal Sq. 
 Head 
 Inch 
 
 Height 
 of Head 
 
 Inch 
 
 y* 
 
 20 
 
 .185 
 
 0062 
 
 %a 
 
 y 2 
 
 M4 
 
 % 
 
 9U 
 
 18 
 
 .240 
 
 .0070 
 
 *H 
 
 ia / 82 
 
 18 Ae 
 
 >4 
 
 % 
 
 16 
 
 .294 
 
 .0078 
 
 2 % 2 
 
 1^6 
 
 8 y 32 
 
 ** 
 
 tte 
 
 14 
 
 .344 
 
 .0089 
 
 * 8 /48 
 
 2 % 2 
 
 1% 
 
 2 %4 
 
 y 2 
 
 13 
 
 .400 
 
 .0096 
 
 1 
 
 % 
 
 1% 
 
 7 /16 
 
 %6 
 
 12 
 
 .454 
 
 .0104 
 
 1%4 
 
 y 32 
 
 1%6 
 
 8 ye4 
 
 % 
 
 11 
 
 .507 
 
 .0113 
 
 ! 7 /82 
 
 IHe 
 
 iy 2 
 
 17 /8 2 
 
 % 
 
 10 
 
 .620 
 
 .0125 
 
 Iftf 
 
 iy* 
 
 1% 
 
 % 
 
 % 
 
 9 
 
 .731 
 
 .0140 
 
 1% 
 
 IT/ie 
 
 2y 82 
 
 28 / 32 
 
 1 
 
 8 
 
 .837 
 
 .0156 
 
 1% 
 
 1% 
 
 2%a 
 
 18 Ae 
 
 1% 
 
 7 
 
 .940 
 
 .0180 
 
 2% 2 
 
 1!%6 
 
 2y 2 
 
 2 % 2 
 
 iy* 
 
 7 
 
 .065 
 
 .0180 
 
 2%e 
 
 2 
 
 22%2 
 
 1 
 
 1% 
 
 6 
 
 .160 
 
 .0210 
 
 2y 2 
 
 2Ae 
 
 3He 
 
 1% 2 
 
 iy 2 
 
 6 
 
 .284 
 
 .0210 
 
 2% 
 
 2% 
 
 3% 
 
 1%6 
 
 1% 
 
 5% 
 
 .389 
 
 .0227 
 
 2i% 9 
 
 2%e 
 
 3% 
 
 1% 2 
 
 i% 
 
 5 
 
 .490 
 
 .0250 
 
 3Ae 
 
 2% 
 
 32% 2 
 
 1% 
 
 1% 
 
 5 
 
 .615 
 
 .0250 
 
 3i% 2 
 
 2i% 6 
 
 4% 6 
 
 U% 2 
 
 2 
 
 4y 2 
 
 .712 
 
 .0280 
 
 3% 
 
 3y 8 
 
 4%e 
 
 1%6 
 
 2^4 
 
 4y 2 
 
 .962 
 
 .0280 
 
 4^6 
 
 3y 2 
 
 48y 82 
 
 18/4 
 
 2y 2 
 
 4 
 
 2.175 
 
 .0310 
 
 4y 2 
 
 3% 
 
 5y 2 
 
 l 1B Ae 
 
 2% 
 
 4 
 
 2.425 
 
 .0310 
 
 429/3 2 
 
 4y 4 
 
 6 
 
 2y 8 
 
 3 
 
 3y 2 
 
 2.628 
 
 .0357 
 
 5% 
 
 4% 
 
 6% 
 
 2%6 
 
 3% 
 
 3y 2 
 
 2.878 
 
 .0357 
 
 5% 
 
 5 
 
 m 
 
 2y 2 
 
 3% 
 
 3H 
 
 3.100 
 
 .0384 
 
 6%4 
 
 5% 
 
 7% 
 
 2i^4o 
 
 3% 
 
 3 
 
 3.317 
 
 .0410 
 
 6% 
 
 5/4 
 
 8%6 
 
 2% 
 
 4 
 
 3 
 
 3.566 
 
 .0410 
 
 7%4 
 
 ey 8 
 
 8H4 6 
 
 3He 
 
 *& 
 
 27/ 8 
 
 3.798 
 
 .0435 
 
 7y 2 
 
 ey 2 
 
 9y 4 
 
 sy 4 
 
 4y 2 
 
 2% 
 
 4.027 
 
 .0460 
 
 7% a 
 
 6% 
 
 9/4 
 
 3%e 
 
 4% 
 
 2% 
 
 4.255 
 
 .0480 
 
 8% 
 
 7y 4 
 
 10% 2 
 
 3% 
 
 5 
 
 2tt 
 
 4.480 
 
 .0500 
 
 8i 3 /i 8 
 
 7% 
 
 101%6 
 
 3i%e 
 
 5V4 
 
 2y 2 
 
 4.730 
 
 .0500 
 
 9^4 
 
 8 
 
 11% 
 
 4 
 
 5% 
 
 2% 
 
 4.953 
 
 .0526 
 
 9iVi6 
 
 8% 
 
 112/32 
 
 4 8 Ae 
 
 53/4 
 
 2% 
 
 5.203 
 
 .0526 
 
 ioy 8 
 
 8/4 
 
 12% 6 
 
 48/ 8 
 
 6 
 
 2y 4 
 
 5.423 
 
 .0555 
 
 10%6 
 
 9y 8 
 
 12% 
 
 4%6 
 
 NOTE. Threads have an angle of 60 degrees, with flat tops and bottoms. 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 381 
 
 STANDARD MACHINE SCREWS 
 
 
 
 
 Diam. 
 
 Diam. of Diam. of 
 
 LENGTHS 
 
 
 No. 
 
 Threads 
 per 
 
 of Body 
 
 of Flat 
 Head 
 
 Round 
 Head 
 
 Filister 
 Head 
 
 
 Clear- 
 ance 
 
 From 
 
 To 
 
 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 Inch 
 
 
 2 
 
 56 
 
 .0842 
 
 .1631 
 
 .1544 
 
 .1332 
 
 % 
 
 % 
 
 41-43 
 
 4 
 
 32, 36, 40 
 
 .1105 
 
 .2158 
 
 .2028 
 
 .1747 
 
 %6 
 
 % 
 
 30-32 
 
 6 
 
 30,32 
 
 .1368 
 
 .2684 
 
 .2512 
 
 .2175 
 
 %8 
 
 1 
 
 27-28 
 
 8 
 
 30,32 
 
 .1631 
 
 .3210 
 
 .2936 
 
 .2610 
 
 % 
 
 1% 
 
 17-18 
 
 10 
 
 24, 30, 32 
 
 .1894 
 
 .3737 
 
 .3480 
 
 .3035 
 
 9i 
 
 1% 
 
 11- 8 
 
 12 
 
 20,24 
 
 .2158 
 
 .4263 
 
 .3922 
 
 .3445 
 
 % 
 
 1% 
 
 2- 1 
 
 14 
 
 20,24 
 
 .2421 
 
 .4790 
 
 .4364 
 
 .3885 
 
 % 
 
 2 
 
 V4 
 
 NOTE. Lengths vary by 16ths from 9io to %, by 8ths from % to 1%, by 
 4ths from 1% to 2. 
 
 STANDARD DIMENSIONS OF WROUGHT-IRON WELDED PIPE 
 BRIGGS' STANDARD 
 
 Nominal 
 Inside 
 Diam. 
 
 Actual 
 Outside 
 Diam. 
 
 Thickness 
 of Metal 
 
 Length of 
 Pipe per 
 Sq. Ft. 
 Outside 
 Surface 
 
 Internal 
 Area 
 
 Weight of 
 Pipe per 
 Lineal Foot 
 
 Number of 
 Threads 
 per Inch 
 
 Ins. 
 
 Ins. 
 
 Ins. 
 
 Ft. 
 
 Sq. In. 
 
 Lbs. 
 
 No. 
 
 14 
 
 .540 
 
 .088 
 
 7.075 
 
 .104 
 
 .42 
 
 18 
 
 % 
 
 .675 
 
 .091 
 
 5.658 
 
 .191 
 
 .56 
 
 18 
 
 % 
 
 .840 
 
 .109 
 
 4.547 
 
 .304 
 
 .84 
 
 14 
 
 % 
 
 1.050 
 
 .113 
 
 3.638 
 
 .533 
 
 1.12 
 
 14 
 
 l 
 
 1.315 
 
 .134 
 
 2.904 
 
 .861 
 
 1.67 
 
 11% 
 
 m 
 
 1.660 
 
 .140 
 
 2.301 
 
 1.496 
 
 2.24 
 
 11% 
 
 1% 
 
 1.900 
 
 .145 
 
 2.010 
 
 2.036 
 
 2.68 
 
 11% 
 
 2 
 
 2.375 
 
 .154 
 
 1.608 
 
 3.356 
 
 3.61 
 
 11% 
 
 2% 
 
 2.875 
 
 .204 
 
 1.329 
 
 4.780 
 
 5.74 
 
 8 
 
 3 
 
 3.500 
 
 .217 
 
 1.091 
 
 7.383 
 
 7.54 
 
 8 
 
 3% 
 
 4.000 
 
 .226 
 
 .955 
 
 9.887 
 
 9.00 
 
 8 
 
 4 
 
 4.500 
 
 .237 
 
 .849 
 
 12.730 
 
 10.66 
 
 8 
 
 41/2 
 
 5.000 
 
 .246 
 
 .764 
 
 15.961 
 
 12.34 
 
 8 
 
 5 
 
 5.563 
 
 .259 
 
 .687 
 
 19.986 
 
 14.50 
 
 8 
 
 6 
 
 6.625 
 
 .280 
 
 .577 
 
 28.890 
 
 18.76 
 
 8 
 
 7 
 
 7.625 
 
 .301 
 
 .501 
 
 38.738 
 
 23.27 
 
 8 
 
 8 
 
 8.625 
 
 .322 
 
 .443 
 
 50.027 
 
 28.18 
 
 8 
 
 9 
 
 9.625 
 
 .344 
 
 .397 
 
 62.730 
 
 33.70 
 
 8 
 
 10 
 
 10.75 
 
 .366 
 
 .355 
 
 78.823 
 
 40.06 
 
 8 
 
382 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 SQUARE HEAD LAG SCREWS 
 
 Diameter 
 in 
 Inches 
 
 %6 
 
 % 
 
 %6 
 
 y 2 
 
 %6 
 
 % 
 
 8 /4 
 
 % 
 
 1 
 
 Length 
 in 
 Inches 
 
 Average Weight per Hundred 
 
 Lbs. Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 1% 
 
 ! 8 /4 
 
 2 
 
 2V 4 
 
 2Y2 
 
 3 
 
 4.2 
 4.7 
 5.2 
 5.7 
 6.2 
 7.2 
 
 6.5 
 7.1 
 
 7.7 
 8.4 
 9.2 
 10.6 
 
 9.2 
 10.0 
 10.9 
 11.8 
 12.7 
 14.6 
 
 13.0 
 13.8 
 14.9 
 16.1 
 17.4 
 19.0 
 
 
 
 
 
 
 
 
 23.0 
 24.5 
 26.0 
 29.2 
 
 24.8 
 27.3 
 29.0 
 32.9 
 
 
 
 
 43.0 
 48.3 
 
 
 
 75.0 
 
 
 B% 
 
 8.2 
 
 12.0 
 
 16.6 
 
 21.5 
 
 32.5 
 
 36.9 
 
 53.8 
 
 78.5 
 
 90 
 
 4 
 
 9.2 
 
 13.5 
 
 18.8 
 
 24.0 
 
 35.9 
 
 41.0 
 
 59.6 
 
 82.0 
 
 99 
 
 4V 2 
 
 10.2 
 
 15.0 
 
 20.7 
 
 26.5 
 
 39.3 
 
 44.9 
 
 65.5 
 
 86.0 
 
 108 
 
 5 
 
 11.3 
 
 16.5 
 
 22.8 
 
 29.0 
 
 42.7 
 
 48.8 
 
 71.5 
 
 90.0 
 
 118 
 
 5% 
 
 12.4 
 
 18.0 
 
 24.9 
 
 31.5 
 
 46.1 
 
 52.7 
 
 77.5 
 
 98.0 
 
 128 
 
 6 
 
 13.5 
 
 19.5 
 
 27.0 
 
 34.0 
 
 49.5 
 
 56.6 
 
 83.5 
 
 106.0 
 
 138 
 
 NOTE. For dimensions of lag screw heads, see page 380. 
 
 COMMON WIRE NAILS 
 
 Size 
 
 Length 
 in 
 Inches 
 
 Diameter 
 in 
 Inches 
 
 Approx. 
 Number to 
 Lb. 
 
 Approx. 
 Lbs. per 
 1000 
 
 2D 
 
 1 
 
 .072 
 
 876 
 
 1.14 
 
 3D 
 
 1% 
 
 .080 
 
 568 
 
 1.76 
 
 4D 
 
 1% 
 
 .100 
 
 316 
 
 3.16 
 
 5D 
 
 1% 
 
 .100 
 
 271 
 
 3.69 
 
 6D 
 
 2 
 
 .113 
 
 181 
 
 5.53 
 
 7D 
 
 21/4 
 
 .113 
 
 161 
 
 6.21 
 
 8D 
 
 2V 2 
 
 .131 
 
 106 
 
 9.43 
 
 9D 
 
 2% 
 
 .131 
 
 96 
 
 10.4 
 
 10D 
 
 3 
 
 .148 
 
 69 
 
 14.5 
 
 12D 
 
 Stt 
 
 .148 
 
 63 
 
 15.9 
 
 16D 
 
 3V 2 
 
 .162 
 
 49 
 
 20.4 
 
 20D 
 
 4 
 
 .192 
 
 31 
 
 32.3 
 
 30D 
 
 4% 
 
 .207 
 
 24 
 
 41.7 
 
 40D 
 
 5 
 
 .225 
 
 18 
 
 55.6 
 
 SOD 
 
 5Va 
 
 .244 
 
 14 
 
 71.4 
 
 60D 
 
 6 
 
 .263 
 
 11 
 
 90.9 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 383 
 
 TABLE OF BOARD MEASURE 
 
 Size 
 
 Length in Feet 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 Feet Board Measure 
 
 1x2 
 
 1% 
 
 2 
 
 2% 
 
 2% 
 
 3 
 
 1 x4 
 
 3% 
 
 4 
 
 4% 
 
 5% 
 
 6 
 
 1 x6 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 1x8 
 
 6% 
 
 8 
 
 9% 
 
 10% 
 
 12 
 
 1x10 
 
 8% 
 
 10 
 
 11% 
 
 131/8 
 
 15 
 
 1x12 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 1 x 14 
 
 11 73 
 
 14 
 
 16% 
 
 18% 
 
 21 
 
 2x4 
 
 6% 
 
 8 
 
 9% 
 
 10% 
 
 12 
 
 2x6 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 2x8 
 
 131/3 
 
 16 
 
 18% 
 
 211/8 
 
 24 
 
 2x10 
 
 16% 
 
 20 
 
 23V 3 
 
 26% 
 
 30 
 
 2x12 
 
 20 
 
 24 
 
 28 
 
 32 
 
 36 
 
 2x14 
 
 231/3 
 
 28 
 
 32% 
 
 37% 
 
 42 
 
 3x8 
 
 20 
 
 24 
 
 28 
 
 32 
 
 36 
 
 3x10 
 
 25 
 
 30 
 
 35 
 
 40 
 
 45 
 
 3x12 
 
 30 
 
 36 
 
 42 
 
 48 
 
 54 
 
 3x14 
 
 35 
 
 42 
 
 49 
 
 56 
 
 63 
 
 4x4 
 
 131/3 
 
 16 
 
 18% 
 
 21% 
 
 24 
 
 4x6 
 
 20 
 
 24 
 
 28 
 
 32 
 
 36 
 
 4x8 
 
 26% 
 
 32 
 
 37% 
 
 42% 
 
 48 
 
 4x 10 
 
 33% 
 
 40 
 
 46% 
 
 53% 
 
 60 
 
 4x12 
 
 40 
 
 48 
 
 56 
 
 64 
 
 72 
 
 4x14 
 
 46% 
 
 56 
 
 65% 
 
 74% 
 
 84 
 
 NOTE. Length in feet X width in feet X thickness in inches number 
 of feet board measure. (1 cu. ft. of lumber = 12 board feet.) 
 
384 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 BAUME'S HYDROMETER AND SPECIFIC GRAVITIES 
 COMPARED 
 
 
 Liquids 
 
 Liquids 
 
 
 Liquids 
 
 Liquids 
 
 Degrees 
 Baume 
 
 Heavier 
 than 
 Water, 
 
 Lighter 
 than 
 Water, 
 
 Degrees 
 Baume 
 
 Heavier 
 than 
 Water, 
 
 Lighter 
 than 
 Water, 
 
 
 Sp. Gr. 
 
 Sp. Gr. 
 
 
 Sp. Gr. 
 
 Sp. Gr. 
 
 0.0 
 
 .000 
 
 
 28.0 
 
 1.239 
 
 0.886 
 
 1.0 
 
 .007 
 
 
 29.0 
 
 1.250 
 
 0.881 
 
 2.0 
 
 .014 
 
 
 30.0 
 
 1.261 
 
 0.875 
 
 3.0 
 
 .021 
 
 
 31.0 
 
 1.272 
 
 0.870 
 
 4.0 
 
 .028 
 
 
 32.0 
 
 1.283 
 
 0.864 
 
 5.0 
 
 .036 
 
 
 33.0 
 
 1.295 
 
 0.859 
 
 6.0 
 
 .043 
 
 
 34.0 
 
 1.306 
 
 0.854 
 
 7.0 
 
 .051 
 
 
 
 35.0 
 
 1.318 
 
 0.849 
 
 8.0 
 
 1.058 
 
 
 36.0 
 
 1.330 
 
 0.843 
 
 9.0 
 
 1.066 
 
 
 37.0 
 
 1.343 
 
 0.838 
 
 10.0 
 
 1.074 
 
 1.000 
 
 38.0 
 
 1.355 
 
 0.833 
 
 11.0 
 
 1.082 
 
 0.993 
 
 39.0 
 
 1.368 
 
 0.828 
 
 12.0 
 
 1.090 
 
 0.986 
 
 40.0 
 
 1.381 
 
 0.824 
 
 13.0 
 
 1.099 
 
 0.979 
 
 41.0 
 
 1.394 
 
 0.819 
 
 14.0 
 
 1.107 
 
 0.972 
 
 42.0 
 
 1.408 
 
 0.814 
 
 15.0 
 
 1.115 
 
 0.966 
 
 44.0 
 
 1.436 
 
 0.805 
 
 16.0 
 
 1.124 
 
 0.959 
 
 46.0 
 
 .465 
 
 0.796 
 
 17.0 
 
 1.133 
 
 0.952 
 
 48.0 
 
 .495 
 
 0.787 
 
 18.0 
 
 1.142 
 
 0.946 
 
 50.0 
 
 .526 
 
 0.778 
 
 19.0 
 
 1.151 
 
 0.940 
 
 52.0 
 
 .559 
 
 0.769 
 
 20.0 
 
 .160 
 
 0.933 
 
 54.0 
 
 .593 
 
 0.761 
 
 21.0 
 
 .169 
 
 0.927 
 
 56.0 
 
 .629 
 
 0.753 
 
 22.0 
 
 .179 
 
 0.921 
 
 58.0 
 
 .667 
 
 0.745 
 
 23.0 
 
 .189 
 
 0.915 
 
 60.0 
 
 .706 
 
 0.737 
 
 24.0 
 
 .198 
 
 0.909 
 
 65.0 
 
 .813 
 
 0.718 
 
 25.0 
 
 .208 
 
 0.903 
 
 70.0 
 
 .933 
 
 0.700 
 
 26.0 
 
 .219 
 
 0.897 
 
 75.0 
 
 2.071 
 
 0.683 
 
 27.0 
 
 .229 
 
 0.892 
 
 
 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 385 
 
 SPECIFIC GRAVITY OF LIQUIDS AT 60 DEGREES FAHR. 
 
 Acid, Muriatic 
 
 1.200 
 
 Oil, Olive, .... 
 
 . 0.92 
 
 
 Acid, Nitric, 
 
 1.217 
 
 Oil, Palm 
 
 . 0.97 
 
 
 Acid, Sulphuric, 
 
 1.849 
 
 Oil, Petroleum, . . 
 
 . 0.78 toO 
 
 88 
 
 Alcohol, pure, 
 
 0.794 
 
 Oil, Rape, .... 
 
 . 0.92 
 
 
 Alcohol, 95 per cent., . . 
 
 0.816 
 
 Oil, Turpentine, . . 
 
 . 0.87 
 
 
 Alcohol, 50 per cent., . . 
 
 0.934 
 
 Oil, Whale, . . . 
 
 . 0.92 
 
 
 Ammonia, 27 .9 per cent., . 
 
 0.891 
 
 Tar, 
 
 . 1. 
 
 
 Bromide, 
 
 2.97 
 
 Vinegar, .... 
 
 . .1.08 
 
 
 Carbon, disulphide, . . . 
 
 1.26 
 
 Water, 
 
 . 1. 
 
 
 Ether, Sulphuric 
 
 0.72 
 
 Water, Sea, . . . 
 
 . 1.026 to 1 
 
 .03 
 
 Oil, Linseed, 
 
 0.94 
 
 
 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
 SPECIFIC GRAVITY AND WEIGHT OF WOOD 
 
 
 Specific 
 Gravity 
 
 Weight per 
 Cubic Foot, 
 Pounds 
 
 
 Specific 
 Gravity 
 
 Weight per I 
 Cubic Foot, 
 Pounds 
 
 
 Avge. 
 
 
 
 
 Avge. 
 
 
 Alder 
 
 0.56 to 0.80 0.68 
 
 42 
 
 Hornbeam, 
 
 0.76 0.76 
 
 47 
 
 Apple 
 
 0.73to0.790.76 
 
 47 
 
 Juniper, . . 
 
 0.56 0.56 
 
 35 
 
 Ash, .... 
 
 0.60to0.840.72 
 
 45 
 
 Larch, . . . 
 
 0.56 056 
 
 35 
 
 Bamboo, . . 
 
 0.31 toO. 40 0.35 
 
 22 
 
 Lignum vitse 
 
 0.65 to 1.33 1.00 
 
 62 
 
 Beech, . . . 
 
 0.62 to 0.85 0.73 
 
 46 
 
 Linden, . . 
 
 0.604 
 
 37 
 
 Birch, .... 
 
 0.56 to 0.74 0.65 
 
 41 
 
 Locust, . . 
 
 0.728 
 
 46 
 
 Box, .... 
 
 0.91 to 1.33 1.12 
 
 70 
 
 Mahogany, . 
 
 0.56 to 1.06 0.81 
 
 51 
 
 Cedar 
 
 0.49 to 0.75 0.62 
 
 39 
 
 Maple,. . . 
 
 0.57 to 0.79 0.68 
 
 42 
 
 Cherry, . . . 
 
 0.61 to 0.72 0.66 
 
 41 
 
 Mulberry, . 
 
 0.56 to 0.90 0.73 
 
 46 
 
 Chestnut, . . 
 
 0.46 to 0.66 0.66 
 
 35 
 
 Oak, Live, . 
 
 0.96 to 1.26 1.11 
 
 69 
 
 Cork 
 
 0.24 0.24 
 
 15 
 
 Oak, White, 
 
 0.69 to 0.86 0.77 
 
 48 
 
 Cypress, . . , 
 
 0.41to0.660.53 
 
 33 
 
 Oak, Red, . 
 
 0.73 to 0.75 0.74 
 
 46 
 
 Dogwood, . . 
 
 0.76 0.76 
 
 47 
 
 Pine, White, 
 
 0.35 to 0.55 0.45 
 
 28 
 
 Ebony, . . . 
 
 1.13 to 1.33 1.23 
 
 76 
 
 Pine.Yellow, 
 
 0.46 to 0.76 0.61 
 
 38 
 
 Elm, .... 
 
 0.55 to 0.78 0.61 
 
 38 
 
 Poplar, . . 
 
 0.38 to 0.58 0.48 
 
 30 
 
 Fir, 
 
 0.48 to 0.70 0.59 
 
 37 
 
 Spruce, . . 
 
 0.40 to 0.50 0.45 
 
 28 
 
 Gum, .... 
 
 0.84 to 1.00 0.92 
 
 57 
 
 Sycamore, . 
 
 0.59 to 0.62 0.60 
 
 37 
 
 Hackmatack, . 
 
 0.59 0.59 
 
 37 
 
 Teak, . . . 
 
 0.66 to 0.98 0.82 
 
 51 
 
 Hemlock, . . 
 
 0.36to0.41 0.38 
 
 24 
 
 Walnut, . . 
 
 0.50 to 0.67 0.58 
 
 36 
 
 Hickory, . . . 
 
 0.69 to 0.94 0.77 
 
 48 
 
 Willow, . . 
 
 0.49 to 0.59 0.54 
 
 34 
 
 Holly 
 
 0.76 0.76 
 
 47 
 
 
 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
386 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 SPECIFIC GRAVITY AND WEIGHT OF STONES, BRICK, 
 CEMENT, ETC. (Pure Waters 1.00.) 
 
 
 Sp. Gr. 
 
 Lb. per Cu. Ft. 
 
 Asphaltum, 
 
 1.39 
 
 87 
 
 Brick, Soft, 
 
 1.6 
 
 100 
 
 Brick, Common, 
 
 1.79 
 
 112 
 
 Brick Hard . 
 
 2 
 
 125 
 
 Brick Pressed 
 
 2 16 
 
 135 
 
 Brick, Fire, 
 
 2.24 to 2. 4 
 
 140 to 150 
 
 Brick Sand-lime 
 
 2 18 
 
 136 
 
 Brickwork in mortar, 
 
 1.6 
 1.79 
 
 100 
 112 
 
 Cement, American, natural, .... 
 Cement, Portland, 
 Cement, Portland, loose, 
 
 2.8 to 3. 2 
 3. 05 to 3. 15 
 
 92 
 
 Cement, Portland, in barrels, . . . 
 Clay 
 
 1 92 to 2 4 
 
 115 
 120 to 150 
 
 Concrete, 
 
 1.92 to 2. 48 
 
 120 to 155 
 
 Earth loose . 
 
 1 15 to 1 28 
 
 72 to 80 
 
 Earth rammed, 
 
 1 44 to 1 .76 
 
 90 to 110 
 
 Emery, 
 
 4. 
 
 250 
 
 Glass . .... 
 
 25 to 2 75 
 
 156 to 172 
 
 Glass, flint, 
 
 2.88 to 3. 14 
 
 180 to 196 
 
 Gneiss 1 
 
 2 56 to 2 72 
 
 160 to 170 
 
 Granite ) 
 Gravel, 
 Gypsum, 
 Hornblende 
 Ice 
 Lime, quick, in bulk 
 Limestone, 
 
 1.6 to 1.92 
 2. 08 to 2. 4 
 3.2 to 3. 52 
 0.88 to 0.92 
 0.8 to 0.96 
 2.30 to 2. 90 
 
 100 to 120 
 130 to 150 
 200 to 220 
 55 to 57 
 50 to 60 
 140 to 185 
 
 Magnesia, Carbonate, 
 Marble 
 Masonry, dry rubble, 
 Masonry, dressed, 
 
 2.4 
 2. 56 to 2. 88 
 2. 24 to 2. 56 
 2.24 to 2. 88 
 
 150 
 160 to 180 
 140 to 160 
 140 to 180 
 
 Mica 
 
 2.80 
 
 175 
 
 Mortar, 
 
 .44 to 1 .6 
 67 to 1.92 
 
 90 to 100 
 104 to 120 
 
 Pitch, 
 
 .15 
 
 72 
 
 Plaster of Paris, 
 Quartz, 
 
 .50 to 1.81 
 .64 
 
 93 to 113 
 165 
 
 Sand . . 
 
 .44 to 1.76 
 
 90 to 110 
 
 Sand, wet, 
 Sandstone 
 
 .89 to 2. 07 
 2.24 to 2. 4 
 
 118 to 129 
 140 to 150 
 
 Slate 
 
 2.72 to 2. 88 
 
 170 to 180 
 
 Soapstone 
 
 2.65 to 2. 8 
 
 166 to 175 
 
 Stone various, 
 
 2.16 to 3. 4 
 
 135 to 200 
 
 Trap, 
 Tile 
 
 2.72 to 3. 4 
 1.76 to 1.92 
 
 170 to 200 
 110 to 120 
 
 Reprinted by permission from Kent's "Mechanical Engineers' Pocket Book.' 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 387 
 
 SPECIFIC GRAVITY AND WEIGHT OF METALS 
 
 
 Specific Gravity. 
 Range According 
 to Several 
 
 Specific Grav- 
 ity. Approx. 
 Mean Value, 
 used in 
 
 Weight 
 per 
 Cubic 
 Foot 
 
 Weight 
 per 
 Cubic 
 Inch 
 
 
 Authorities 
 
 Oo,lculntion of 
 Weight 
 
 Lbs. 
 
 Lbs. 
 
 Aluminum, .... 
 
 2.56 to 2.71 
 
 2.67 
 
 166.5 
 
 0.0963 
 
 Antimony 
 
 6.66 to 6.86 
 
 6.76 
 
 421.6 
 
 0.2439 
 
 Bismuth, 
 
 9.74 to 9.90 
 
 9.82 
 
 612.4 
 
 0.3544 
 
 Brass: Copper-fZinc 
 
 
 
 
 
 80 20 1 
 
 
 rs.eo 
 
 536.3 
 
 0.3103 
 
 70 30 1 
 60 40 ( 
 50 50 J 
 
 7.8 to 8.6 
 
 J 8.40 
 1 8.36 
 [8.20 
 
 523.8 
 521.3 
 511.4 
 
 0.3031 
 0.3017 
 0.2959 
 
 (Cop., 95 to 80 ) 
 Bronze lTin, 5 to 20 \ 
 
 8.52 to 8.96 
 
 8.853 
 
 552. 
 
 0.3195 
 
 Cttdmiuin 
 
 8.6 to 8.7 
 
 8.65 
 
 539. 
 
 0.3121 
 
 Calcium 
 
 1.58 
 
 1.58 
 
 98.5 
 
 0.0570 
 
 Chromium, 
 
 5.0 
 
 5.0 
 
 311.8 
 
 0.1804 
 
 Cobalt 
 
 8.5 to 8.6 
 
 8.55 
 
 533.1 
 
 0.3085 
 
 Gold, pure 
 
 19.245 to 19.361 
 
 19.258 
 
 1200.9 
 
 .6949 
 
 Copper . . . 
 
 8.69 to 8.92 
 
 8.853 
 
 552. 
 
 0.3195 
 
 Indium, 
 
 22.38 to 23. 
 
 22.38 
 
 1396. 
 
 0.8076 
 
 Iron, Cast, 
 
 6.85 to 7.48 
 
 7.218 
 
 450. 
 
 0.2604 
 
 Iron, Wrought, . . . 
 
 7.4 to 7.9 
 
 7.70 
 
 480. 
 
 0.2779 
 
 Lead 
 
 11 .07 to 11 .44 
 
 11.38 
 
 709.7 
 
 o.'Jioe 
 
 Manganese, 
 
 7. to 8. 
 
 8. 
 
 499. 
 
 0.2887 
 
 Magnesium, 
 
 1.69 to 1.75 
 
 1.75 
 
 109. 
 
 0.0641 
 
 {32 
 
 13.60 to 13. 62 
 
 13.62 
 
 849.3 
 
 0.4915 
 
 60 
 
 13.58 
 
 13.58 
 
 846.8 
 
 0.4900 
 
 212 
 
 13.37 to 13. 38 
 
 13.38 
 
 834.4 
 
 0.4828 
 
 Nickel 
 
 8. 279 to 8.93 
 
 8.8 
 
 548.7 
 
 0.3175 
 
 Platinum 
 
 20.33 to 22 .07 
 
 21.5 
 
 1347.0 
 
 0.7758 
 
 Potassium 
 
 0.865 
 
 0.865 
 
 53.9 
 
 0.0312 
 
 Silver, 
 
 10.474 to 10.511 
 
 10.505 
 
 655.1 
 
 0.3791 
 
 Sodium, 
 
 0.97 
 
 0.97 
 
 60.5 
 
 0.0350 
 
 Steel 
 
 7.69* to 7.93?t 
 
 7.854 
 
 "489 . 6 
 
 . 2834 
 
 Tin, ' 
 
 7. 291 to 7.409 
 
 7.350 
 
 458.3 
 
 0.2652 
 
 Titanium . 
 
 5.3 
 
 5.3 
 
 330.5 
 
 0.1913 
 
 Tungsten, 
 
 17. to 17. 6 
 
 17.3 
 
 1078.7 
 
 0.6243 
 
 Zinc 
 
 6.86 to 7.20 
 
 7.00 
 
 436.5 
 
 0.2526 
 
 
 
 
 
 
 * Hard and burned. 
 
 t Very pure and soft. The sp. gr. decreases as the carbon is increased. 
 
 In the first column of figures the lowest are usually those of cast metals, 
 which are more or less porous; the highest are of metals finely rolled or 
 drawn into wire. 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
 
388 GENERAL RAILWAY SIGNAL COMPANY 
 
 TABLES OF WEIGHTS AND MEASURES 
 LINEAR MEASURE 
 
 12 inches (in.), .... =1 foot (ft.) 
 
 3 feet, =1 yard (yd.) 
 
 5. 5 yards, =lrod(rd.) 
 
 40 rods, =-1 furlong (fur.) 
 
 8 furlongs, =1 mile (mi.) 
 
 1 mi. -8 fur. =320 rods -1760 yd. -=5280 ft. = 63, 360 in. 
 
 SQUARE MEASURE 
 
 144 square inches (sq. in.), =1 square foot (sq. ft.) 
 
 9 square feet, .... =1 square yard (sq. yd.) 
 30*4 square yards,. ... =1 square rod (sq. rd.) 
 
 160 square rods, . . . . = 1 acre (A) 
 
 640 acres, =1 square mile (sq. mi.) 
 
 1 sq. mi. -640 acres = 102,400 sq. rd. =3,097,600 sq. yd.= 
 27,878,400 sq. ft. =4,014,489,600 sq. in. 
 
 CUBIC MEASURE 
 
 1,728 cubic inches (cu. in.), =1 cubic foot (cu. ft.) 
 
 27 cubic feet, =1 cubic yard (cu. yd.) 
 
 128 cubic feet, =lcord(cd.) 
 
 24% cubic feet, =1 perch (P.) 
 
 1 cu. yd. =27 cu. ft. =46, 656 cu. in. 
 
 MEASURES OP ANGLES OR ARCS 
 
 60 seconds ("), .... =1 minute (0 
 
 60 minutes, =1 degree () 
 
 90 degrees, =1 right angle or quadrant ( D ) 
 
 360 degrees, =1 circle (cir.) 
 
 1 cir. =360 = 21,600' = 1,296,000". 
 
 AVOIRDUPOIS WEIGHT 
 
 437.5 grains (gr.), .... =1 ounce (oz.) 
 
 16 ounces, =1 pound (Ib.) 
 
 100 pounds, =1 hundredweight (cwt.) 
 
 20 cwt. or 2,000 Ib., . . =1 ton (T.) 
 1 T. =20 cwt. = 2,000 Ib. =32,000 oz. = 14,000,000 gr. 
 The avoirdupois pound contains 7,000 grains. 
 
 DRY MEASURE , 
 
 2 pints (pt.), =1 quart (qt.) 
 
 8 quarts, =1 peck (pk.) 
 
 4 pecks, = 1 bushel (bu.) 
 
 1 bu.=4 pk. = 32 qt. = 64 pt. 
 
 The U. S. struck bushel contains 2,150.42 cubic inches = 
 1.2444 cubic feet. By law, its dimensions are those of a 
 cylinder 18V2 inches in diameter and 8 inches deep. The 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 389 
 
 heaped bushel is equal to 1 1 A struck bushels, the cone being 
 six inches high. The dry gallon contains 268.8 cubic inches, 
 being % of a struck bushel. 
 
 For approximations, the bushel may be taken at 1}4 cubic 
 feet, or a cubic foot may be considered % of a bushel. 
 
 The British bushel contains 2,218.19 cubic inches -1.2837 
 cubic feet = 1.032 U. S. bushels. 
 
 LIQUID MEASURE 
 
 4 gills (gi.), = lpint(pt.) 
 
 2 pints, =1 quart (qt.) 
 
 4 quarts, =1 gallon (gal.) 
 
 3iy 2 gallons, ...... =1 barrel (bbl.) 
 
 2 barrels, = 1 hogshead (hhd.) 
 
 1 hhd. =2 bbl. = 63 gal. =252 qt. = 504 pt. = 2,016 gi. 
 
 The U. S. gallon contains 231 cubic inches = .134 cubic feet 
 approximate ; or 1 cubic foot contains 7.481 gallons. The fol- 
 lowing cylinders contain the given measures very closely : 
 
 Diam. Height 
 
 Gill, 1% in. 3 in. 
 
 Pint, 3V2 in. 3 in. 
 
 Quart, .... 3 J /2 in. 6 in. 
 
 Gallon, . 
 
 8 gallons, 
 
 10 gallons, 
 
 Diam. Height 
 
 7 in. 6 in. 
 
 14 in. 12 in. 
 
 14 in. 15 in. 
 
 foot 
 
 When water is at its maximum density, 1 cubic 
 weighs 62.425 pounds and 1 gallon weighs 8.345 pounds. 
 
 For approximations, 1 cubic foot of water is considered 
 equal to 1V-2 gallons and 1 gallon as weighing 8Vs pounds. 
 
 The British Imperial gallon, both liquid and dry, contains 
 277.274 cubic inches =.16046 cubic feet, and is equivalent to 
 the volume of 10 pounds of pure water at 62 degrees Fahr. 
 To reduce British to U. S. liquid gallons, multiply by 1.2. Con- 
 versely, to convert U. S. into British liquid gallons, divide 
 by 1.2; or, increase the number of gallons 3 /5. 
 
 MISCELLANEOUS TABLE 
 
 12 articles, =1 dozen. 
 
 12 dozen, ==1 gross. 
 
 12 gross, = 1 great gross. 
 
 2 articles, =1 pair. 
 
 20 articles, =1 score. 
 
 24 sheets, =1 quire. 
 
 20 quires, =1 ream. 
 
390 GENERAL RAILWAY SIGNAL COMPANY 
 
 FRENCH OR METRIC MEASURE 
 
 The metric unit of length is the metre = 39. 37 inches. 
 
 The metric unit of weight is the gram = 15.432 grains. 
 
 The following prefixes are used for subdivisions and multi- 
 ples: Milli = 1/1000, Centi = 1/100, Deci = l/10, Deca = 10, 
 Hecto = 100, Kilo = 1000, Myria = 10,000. 
 
 FRENCH EQUIVALENTS OF AMERICAN AND 
 BRITISH MEASURE 
 
 MEASURES OP LENGTH 
 
 French British and U. S. 
 
 (39.37 inches 
 
 1 metre, = ' or 3.28083 feet 
 
 ( or 1.09361 yards 
 
 .3048 metre, =1 foot 
 
 1 centimetre, = .3937 inch 
 
 2.54 centimetres, =1 inch 
 
 1 millimetre, 
 
 25.4 millimetres, =1 inch 
 
 1 kilometre, = j 1093.. 61 yard 
 
 0.62137 mile 
 
 MEASURES OF SURFACE 
 French British and U. S, 
 
 ( 10.764 square feet 
 1 square metre, -= -j 1496 square yard 
 
 .836 square metre, =1 square yard 
 
 .0929 square metre, =1 square foot 
 
 1 square centimetre, =.155 square inch 
 
 2 square centimetres, . . . . = 1 square inch 
 
 6.452 square centimetres 
 1 square millimetre, 
 
 f .00155 square inch 
 \ 1973.5 circular mils. 
 645.2 square millimetres, . . . . = 1 square inch 
 
 1 centiare = l square metre,. . =10.764 square feet 
 1 are = 1 square decametre, . . =1076.41 square feet 
 
 1AA ( 107641 square feet 
 
 1 hectare = 100 ares, == j 2.4711 acres 
 
 , ., / .386109 square mile 
 
 1 square kilometre, m < 247 11 acres 
 
 1 square myriametre, .... =38.6109 square miles 
 
 Reprinted by permission from " Kent's Mechanical Engineer's Pocket Book." 
 
ELECTRIC INTERLOCKING HANDBOOK 391 
 
 MEASURES OF VOLUME 
 French British and U. S. 
 
 { 35.314 cubic feet 
 1 cubic metre, = ] 1.308 cubic yards 
 
 .7645 cubic metre, =1 cubic yard 
 
 .02832 cubic metre, =1 cubic foot 
 
 1 cubic decimetre, : 
 
 28.32 cubic decimetres, ..... =1 cubic foot 
 
 1 cubic centimetre, ..... =.061 cubic inch 
 
 16.387 cubic centimetres, ..... =1 cubic inch 
 
 1 cubic centimetre = 1 millilitre, = .061 cubic inch 
 
 1 centilitre, ......... = .610 cubic inch 
 
 1 decilitre, ......... =6.102 cubic inches 
 
 1 litres cubic decimetre, . - | 
 
 1 hectolitre or decistere, . . . = m . S 
 
 1 stere, kilolitre, or cubic metre, - { 
 
 MEASURES OF CAPACITY 
 French British and U. S. 
 
 (61.023 cubic inches 
 .03531 cubic foot 
 .2642 gallon (Am.) 
 2.202 pounds of 
 water at 62 Fahr. 
 28.317 litres, .......... =1 cubic foot 
 
 4.543 litres, .......... =1 gallon (British) 
 
 3.785 litres, .......... =1 gallon (American) 
 
 MEASURES OF WEIGHT 
 
 French British and U. S. 
 
 1 gramme, ......... = 15.432 grains 
 
 .0648 gramme, ......... =1 grain . 
 
 28.35 grammes, ......... = 1 ounce avoirdupois 
 
 1 kilogramme, ....... =2.2046 pounds 
 
 .4536 kilogramme ........ =1 pound 
 
 f.9842 ton of 2,240 
 
 1 tonne or metric ton, pounds 
 
 1,000 kilogrammes, ....... =1 19.68 cwts. 
 
 i. 2204.6 pounds 
 
 1.016 metric tons, = [1 ton of 2,240 
 
 1,016 kilogrammes, ....... = [pounds 
 
 Reprinted by permission from, "Kent's Mechanical Engineers' Pocket Book." 
 
392 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 TEMPERATURES, FAHRENHEIT AND CENTIGRADE 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. || F. 
 
 C. F. 
 
 C. 
 
 -40 
 
 40. 
 
 26 
 
 3.3 
 
 92 
 
 33.3 
 
 158 
 
 70. 
 
 224 
 
 106.7 
 
 290 
 
 143.3 
 
 360 
 
 182.2 
 
 39 
 
 39.4 
 
 27 
 
 2.8 
 
 93 
 
 33.9 
 
 159 
 
 70.6 
 
 225 
 
 107.2 
 
 291 
 
 143.9 
 
 370 
 
 187.8 
 
 -38 
 
 -38.9 
 
 28 
 
 2.2 
 
 94 
 
 34.4 
 
 160 
 
 71.1 
 
 226 
 
 107.8 
 
 292 
 
 144.4 
 
 380 
 
 193.3 
 
 37 
 
 38.3 
 
 29 
 
 -1.7 
 
 95 
 
 35. 
 
 161 
 
 71.7 
 
 227 
 
 108.3 
 
 293 
 
 145. 
 
 390 
 
 198.9 
 
 -36 
 
 37.8 
 
 30 
 
 1.1 
 
 96 
 
 35.6 
 
 162 
 
 72.2 
 
 228 
 
 108.9 
 
 294 
 
 145.6 
 
 400 
 
 204.4 
 
 35 
 
 -37.2 
 
 31 
 
 -0.6 
 
 97 
 
 36.1 
 
 163 
 
 72.8 
 
 229 
 
 109.4 
 
 295 
 
 146.1 
 
 410 
 
 210. 
 
 34 
 
 -36.7 
 
 32 
 
 0. 
 
 98 
 
 36.7 
 
 164 
 
 73.3 
 
 230 
 
 110. 
 
 296 
 
 146.7 
 
 420 
 
 215.6 
 
 33 
 
 -36.1 
 
 33 
 
 +0.6 
 
 99 
 
 37.2 
 
 165 
 
 73.9 
 
 231 
 
 110.6 
 
 297 
 
 147.2 
 
 430 
 
 221.1 
 
 -32 
 
 35.6 
 
 34 
 
 1.1 
 
 100 
 
 37.8 
 
 166 
 
 74.4 
 
 232 
 
 111.1 
 
 298 
 
 147.8 
 
 440 
 
 226.7 
 
 31 
 
 -35. 
 
 35 
 
 1.7 
 
 101 
 
 38.3 
 
 167 
 
 75. 
 
 233 
 
 111.7 
 
 299 
 
 148.3 
 
 450 
 
 232.2 
 
 -30 
 
 34.4 
 
 36 
 
 2.2 
 
 102 
 
 38.9 
 
 168 
 
 75.6 
 
 234 
 
 112.2 
 
 300 
 
 148.9 
 
 460 
 
 237.8 
 
 -29 
 
 -33.9 
 
 37 
 
 2.8 
 
 103 
 
 39.4 
 
 169 
 
 76.1 
 
 235 
 
 112.8 
 
 301 
 
 149.4 
 
 470 
 
 243.3 
 
 28 
 
 33.3 
 
 38 
 
 3.3 
 
 104 
 
 40. 
 
 170 
 
 76.7 
 
 236 
 
 113.3 
 
 302 
 
 150. 
 
 480 
 
 248.9 
 
 27 
 
 -32.8 
 
 39 
 
 3.9 
 
 105 
 
 40.6 
 
 171 
 
 77.2 
 
 237 
 
 113.9 
 
 303 
 
 150.6 
 
 490 
 
 254.4 
 
 26 
 
 32.2 
 
 40 
 
 4.4 
 
 106 
 
 41.1 
 
 172 
 
 77.8 
 
 238 
 
 114.4 
 
 304 
 
 151.1 
 
 500 
 
 260. 
 
 -25 
 
 -31.7 
 
 41 
 
 5. 
 
 107 
 
 41.7 
 
 173 
 
 78.3 
 
 239 
 
 115. 
 
 305 
 
 151.7 
 
 510 
 
 265.6 
 
 24 
 
 31.1 
 
 42 
 
 5.6 
 
 108 
 
 42.2 
 
 174 
 
 78.9 
 
 240 
 
 115.6 
 
 306 
 
 152.2 
 
 520 
 
 271.1 
 
 -23 
 
 -30.6 
 
 43 
 
 6.1 
 
 109 
 
 42.8 
 
 175 
 
 79.4 
 
 241 
 
 116.1 
 
 307 
 
 152.8 
 
 530 
 
 276.7 
 
 22 
 
 -30. 
 
 44 
 
 6.7 
 
 110 
 
 43.3 
 
 176 
 
 80. 
 
 242 
 
 116.7 
 
 308 
 
 153.3 
 
 540 
 
 282.2 
 
 -21 
 
 29.4 
 
 45 
 
 7.2 
 
 111 
 
 43.9 
 
 177 
 
 80.6 
 
 243 
 
 117.2 
 
 309 
 
 153.9 
 
 550 
 
 287.8 
 
 20 
 
 -28.9 
 
 46 
 
 7.8 
 
 112 
 
 44.4 
 
 178 
 
 81.1 
 
 244 
 
 117.8 
 
 310 
 
 154.4 
 
 560 
 
 293.3 
 
 -19 
 
 -28.3 
 
 47 
 
 8.3 
 
 113 
 
 45. 
 
 179 
 
 81.7 
 
 245 
 
 118.3 
 
 311 
 
 155. 
 
 570 
 
 298.9 
 
 18 
 
 27.8 
 
 48 
 
 8.9 
 
 114 
 
 45.6 
 
 180 
 
 82.2 
 
 246 
 
 118.9 
 
 312 
 
 155.6 
 
 580 
 
 304.4 
 
 17 
 
 -27.2 
 
 49 
 
 9.4 
 
 115 
 
 46.1 
 
 181 
 
 82.8 
 
 247 
 
 119.4 
 
 313 
 
 156.1 
 
 590 
 
 310. 
 
 16 
 
 -26.7 
 
 50 
 
 10. 
 
 116 
 
 46.7 
 
 182 
 
 83.3 
 
 248 
 
 120. 
 
 314 
 
 156.7 
 
 600 
 
 315.6 
 
 15 
 
 26.1 
 
 51 
 
 10.6 
 
 117 
 
 47.2 
 
 183 
 
 83.9 
 
 249 
 
 120.6 
 
 315 
 
 157.2 
 
 610 
 
 321.1 
 
 14 
 
 25.6 
 
 52 
 
 11.1 
 
 118 
 
 47.8 
 
 184 
 
 84.4 
 
 250 
 
 121.1 
 
 316 
 
 157.8 
 
 620 
 
 326.7 
 
 -13 
 
 -25. 
 
 53 
 
 11.7 
 
 119 
 
 48.3 
 
 185 
 
 85. 
 
 251 
 
 121.7 
 
 317 
 
 158.3 
 
 630 332.2 
 
 12 
 
 24.4 
 
 54 
 
 12.2 
 
 120 
 
 48.9 
 
 186 
 
 85.6 
 
 252 
 
 122.2 
 
 318 
 
 158.9 
 
 640 337.8 
 
 11 
 
 -23.9 
 
 55 
 
 12.8 
 
 121 
 
 49.4 
 
 187 
 
 86.1 
 
 253 
 
 122.8 
 
 319 
 
 159.4 
 
 650 343.3 
 
 10 
 
 -23.3 
 
 56 
 
 13.3 
 
 122 
 
 50. 
 
 188 
 
 86.7 
 
 254 
 
 123.3 
 
 320 
 
 160. 
 
 660 348.9 
 
 9 
 
 22.8 
 
 57 
 
 13.9 
 
 123 
 
 50.6 
 
 189 
 
 87.2 
 
 255 
 
 123.9 
 
 321 
 
 160.6 
 
 670 354.4 
 
 8 
 
 -22.2 
 
 58 
 
 14.4 
 
 124 
 
 51.1 
 
 190 
 
 87.8 
 
 256 
 
 124.4 
 
 322 
 
 161.1 
 
 680 360. 
 
 7 
 
 21.7 
 
 59 
 
 15. 
 
 125 
 
 51.7 
 
 191 
 
 88.3 
 
 257 
 
 125. 
 
 323 
 
 161.7 
 
 690 J365.6 
 
 6 
 
 21.1 
 
 60 
 
 15.6 
 
 126 
 
 52.2 
 
 192 
 
 88.9 
 
 258 
 
 125.6 
 
 324 
 
 162.2 
 
 700 371.1 
 
 5 
 
 20.6 
 
 61 
 
 16.1 
 
 127 
 
 52.8 
 
 193 
 
 89.4 
 
 259 
 
 126.1 
 
 325 
 
 162.8 
 
 710 |376.7 
 
 4 
 
 -20. 
 
 62 
 
 16.7 
 
 128 
 
 53.3 
 
 194 
 
 90. 
 
 260 
 
 126.7 
 
 326 
 
 163.3 
 
 720 
 
 382.2 
 
 3 
 
 19.4 
 
 63 
 
 17.2 
 
 129 
 
 53.9 
 
 195 
 
 90.6 
 
 261 
 
 127.2 
 
 327 
 
 163.9 
 
 730 
 
 387.8 
 
 2 
 
 -18.9 
 
 64 
 
 17.8 
 
 130 
 
 54.4 
 
 196 
 
 91.1 
 
 262 
 
 127.8 
 
 328 
 
 164.4 
 
 740 
 
 393.3 
 
 * 
 
 18.3 
 
 65 
 
 18.3 
 
 131 
 
 55. 
 
 197 
 
 91.7 
 
 263 
 
 128.3 
 
 329 
 
 165. 
 
 750 
 
 398.9 
 
 
 
 17.8 
 
 66 
 
 18.9 
 
 132 
 
 55.6 
 
 198 
 
 92.2 
 
 264 
 
 128.9 
 
 330 
 
 165.6 
 
 760 
 
 404.4 
 
 + 1 
 
 17.2 
 
 67 
 
 19.4 
 
 133 
 
 56.1 
 
 199 
 
 92.8 
 
 265 
 
 129.4 
 
 331 
 
 166.1 
 
 770 
 
 410. 
 
 2 
 
 16.7 
 
 68 
 
 20. 
 
 134 
 
 56.7 
 
 200 
 
 93.3 
 
 266 
 
 130. 
 
 332 
 
 166.7 
 
 780 
 
 415.6 
 
 3 
 
 16.1 
 
 69 
 
 20.6 
 
 135 
 
 57.2 
 
 201 
 
 93.9 
 
 267 
 
 130.6 
 
 333 
 
 167.2 
 
 790 
 
 421.1 
 
 4 
 
 15.6 
 
 70 
 
 21.1 
 
 136 
 
 57.8 
 
 202 
 
 94.4 
 
 268 
 
 131.1 
 
 334 
 
 167.8 
 
 800 
 
 426.7 
 
 5 
 
 15. 
 
 71 
 
 21.7 
 
 137 
 
 58.3 
 
 203 
 
 95. 
 
 269 
 
 131.7 
 
 335 
 
 168.3 
 
 810 
 
 432.2 
 
 6 
 
 14.4 
 
 72 
 
 22.2 
 
 138 
 
 58.9 
 
 204 
 
 95.6 
 
 270 
 
 132.2 
 
 336 
 
 168.9 
 
 820 
 
 437.8 
 
 7 
 
 -13.9 
 
 73 
 
 22.8 
 
 139 
 
 59.4 
 
 205 
 
 96.1 
 
 271 
 
 132.8 
 
 337 
 
 169.4 
 
 830 
 
 443.3 
 
 8 
 
 13.3 
 
 74 
 
 23.3 
 
 140 
 
 60. 
 
 206 
 
 96.7 
 
 272 
 
 133.3 
 
 338 
 
 170. 
 
 840 
 
 448.9 
 
 9 
 
 -12.8 
 
 75 
 
 23.9 
 
 141 
 
 60.6 
 
 207 
 
 97.2 
 
 273 
 
 133.9 
 
 339 
 
 170.6 
 
 850 
 
 454.4 
 
 10 
 
 12.2 
 
 76 
 
 24.4 
 
 142 
 
 61.1 
 
 208 
 
 97.8 
 
 274 
 
 134.4 
 
 340 
 
 171.1 
 
 860 
 
 460. 
 
 11 
 
 11.7 
 
 77 
 
 25. 
 
 143 
 
 61.7 
 
 209 
 
 98.3 
 
 275 
 
 135. 
 
 341 
 
 171.7 
 
 870 
 
 465.6 
 
 12 
 
 11.1 
 
 78 
 
 25.6 
 
 144 
 
 62.2 
 
 210 
 
 98.9 
 
 276 
 
 135.6 
 
 342 
 
 172.2 
 
 880 
 
 471.1 
 
 13 
 
 10.6 
 
 79 
 
 26.1 
 
 145 
 
 62.8 
 
 211 
 
 99.4 
 
 277 
 
 136.1 
 
 343 
 
 172.8 
 
 890 
 
 476.7 
 
 14 
 
 10. 
 
 80 
 
 26.7 
 
 146 
 
 63.3 
 
 212 
 
 100. 
 
 278 
 
 136.7 
 
 344 
 
 173.3 
 
 900 
 
 482.2 
 
 15 
 
 9.4 
 
 81 
 
 27.2 
 
 147 
 
 63.9 
 
 213 
 
 100.6 
 
 279 
 
 137.2 
 
 345 
 
 173.9 
 
 910 
 
 487.8 
 
 16 
 
 8.9 
 
 82 
 
 27.8 
 
 148 
 
 64.4 
 
 214 
 
 101.1 
 
 280 
 
 137.8 
 
 346 
 
 174.4 
 
 920 
 
 493.3 
 
 17 
 
 8.3 
 
 83 
 
 28.3 
 
 149 
 
 65. 
 
 215 
 
 101.7 
 
 281 
 
 138.3 
 
 347 
 
 175. 
 
 930 
 
 498.9 
 
 18 
 
 7.8 
 
 84 
 
 28.9 
 
 150 
 
 65.6 
 
 216 
 
 102.2 
 
 282 
 
 138.9 
 
 348 
 
 175.6 
 
 940 
 
 504.4 
 
 19 
 
 - 7.2 
 
 85 
 
 29.4 
 
 151 
 
 66.1 
 
 217 
 
 102.8 
 
 283 
 
 139.4 
 
 349 
 
 176.1 
 
 950 
 
 510. 
 
 20 
 
 6.7 
 
 86 
 
 30. 
 
 152 
 
 66.7 
 
 218 
 
 103.3 
 
 284 
 
 140. 
 
 350 
 
 176.7 
 
 960 
 
 515.6 
 
 21 
 
 6.1 
 
 87 
 
 30.6 
 
 153 
 
 67.2 
 
 219 
 
 103.9 
 
 285 
 
 140.6 
 
 351 
 
 177.2 
 
 970 
 
 521.1 
 
 22 
 
 5.6 
 
 88 
 
 31.1 
 
 154 
 
 67.8 
 
 220 
 
 104.4 
 
 286 
 
 141.1 
 
 352 
 
 177.8 
 
 980 
 
 526.7 
 
 23 
 
 5. 
 
 89 
 
 31.7 
 
 155 
 
 68.3 
 
 221 
 
 105. 
 
 287 
 
 141.7 
 
 353 
 
 178.3 
 
 990 
 
 532.2 
 
 24 
 
 4.4 
 
 90 
 
 32.2 
 
 156 
 
 68.9 
 
 222 
 
 105.6 
 
 288 
 
 142.2 
 
 354 
 
 178.9 
 
 1000 
 
 537.8 
 
 25 
 
 3.9 
 
 91 
 
 32.8 
 
 157 
 
 69.4 
 
 223 
 
 106.1 
 
 289 
 
 142.8 
 
 355 
 
 179.41010 
 
 543 3 
 
 Reprinted by -permission from "Kent's Mechanical Engineers' Pocket Book." 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 393 
 
 TEMPERATURES, CENTIGRADE AND FAHRENHEIT 
 
 c. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 C. 
 
 F. 
 
 40 
 
 -40. 
 
 26 
 
 78.8 
 
 92 
 
 197.6 
 
 158 
 
 316.4 
 
 224 
 
 435.2 
 
 290 
 
 554 
 
 950 
 
 1742 
 
 39 
 
 38.2 
 
 27 
 
 80.6 
 
 93 
 
 199.4 
 
 159 
 
 318.2 
 
 225 
 
 437. 
 
 300 
 
 572 
 
 960 
 
 1760 
 
 38 
 
 36.4 
 
 28 
 
 82.4 
 
 94 
 
 201.2 
 
 160 
 
 320. 
 
 226 
 
 438.8 
 
 310 
 
 590 
 
 970 
 
 1778 
 
 37 
 
 34.6 
 
 29 
 
 84.2 
 
 95 
 
 203. 
 
 161 
 
 321.8 
 
 227 
 
 440.6 
 
 320 
 
 608 
 
 980 
 
 1796 
 
 -36 
 
 -32.8 
 
 30 
 
 86. 
 
 96 
 
 204.8 
 
 162 
 
 323.6 
 
 228 
 
 442.4 
 
 330 
 
 626 
 
 990 
 
 1814 
 
 -35 
 
 -31. 
 
 31 
 
 87.8 
 
 97 
 
 206.6 
 
 163 
 
 325.4 
 
 229 
 
 444.2 
 
 340 
 
 644 
 
 1000 
 
 1832 
 
 34 
 
 29.2 
 
 32 
 
 89.6 
 
 98 
 
 208.4 
 
 164 
 
 327.2 
 
 230 
 
 446. 
 
 350 
 
 662 
 
 1010 
 
 1850 
 
 -33 
 
 -27.4 
 
 33 
 
 91.4 
 
 99 
 
 210.2 
 
 165 
 
 329. 
 
 231 
 
 447.8 
 
 360 
 
 680 
 
 1020 
 
 1868 
 
 32 
 
 -25.6 
 
 34 
 
 93.2 
 
 100 
 
 212. 
 
 166 
 
 330.8 
 
 232 
 
 449.6 
 
 370 
 
 698 
 
 1030 
 
 1886 
 
 -31 
 
 23.8 
 
 35 
 
 95. 
 
 101 
 
 213.8 
 
 167 
 
 332.6 
 
 233 
 
 451.4 
 
 380 
 
 716 
 
 1040 
 
 1904 
 
 30 
 
 22. 
 
 36 
 
 96.8 
 
 102 
 
 215.6 
 
 168 
 
 334.4 
 
 234 
 
 453.2 
 
 390 
 
 734 
 
 1050 
 
 1922 
 
 29 
 
 20.2 
 
 37 
 
 98.6 
 
 103 
 
 217.4 
 
 169 
 
 336.2 
 
 235 
 
 455. 
 
 400 
 
 752 
 
 1060 
 
 1940 
 
 -28 
 
 -18.4 
 
 38 
 
 100.4 
 
 104 
 
 219.2 
 
 170 
 
 338. 
 
 236 
 
 456.8 
 
 410 
 
 770 
 
 1070 
 
 1958 
 
 27 
 
 16.6 
 
 39 
 
 102.2 
 
 105 
 
 221. 
 
 171 
 
 339.8 
 
 237 
 
 458.6 
 
 420 
 
 788 
 
 1080 
 
 1976 
 
 26 
 
 14.8 
 
 40 
 
 104. 
 
 106 
 
 222.8 
 
 172 
 
 341.6 
 
 238 
 
 460.4 
 
 430 
 
 806 
 
 1090 
 
 1994 
 
 25 
 
 -13. 
 
 41 
 
 105.8 
 
 107 
 
 224.6 
 
 173 
 
 343.4 
 
 239 
 
 462.2 
 
 440 
 
 824 
 
 1100 
 
 2012 
 
 24 
 
 -11.2 
 
 42 
 
 107.6 
 
 108 
 
 226.4 
 
 174 
 
 345.2 
 
 240 
 
 464. 
 
 450 
 
 842 
 
 1110 
 
 2030 
 
 23 
 
 9.4 
 
 43 
 
 109.4 
 
 109 
 
 228.2 
 
 175 
 
 347. 
 
 241 
 
 465.8 
 
 460 
 
 860 
 
 1120 
 
 2048 
 
 22 
 
 7.6 
 
 44 
 
 111.2 
 
 110 
 
 230. 
 
 176 
 
 348.8 
 
 242 
 
 467.6 
 
 470 
 
 878 
 
 1130 
 
 2066 
 
 21 
 
 -5.8 
 
 45 
 
 113. 
 
 111 
 
 231.8 
 
 177 
 
 350.6 
 
 243 
 
 469.4 
 
 480 
 
 896 
 
 1140 
 
 2084 
 
 -20 
 
 4. 
 
 46 
 
 114.8 
 
 112 
 
 233.6 
 
 178 
 
 352.4 
 
 244 
 
 471.2 
 
 490 
 
 914 
 
 1150 
 
 2102 
 
 19 
 
 2.2 
 
 47 
 
 116.6 
 
 113 
 
 235.4 
 
 179 
 
 354.2 
 
 245 
 
 473. 
 
 500 
 
 932 
 
 1160 
 
 2120 
 
 18 
 
 0.4 
 
 48 
 
 118.4 
 
 114 
 
 237.2 
 
 180 
 
 356. 
 
 246 
 
 474.8 
 
 510 
 
 950 
 
 1170 
 
 2138 
 
 -17 
 
 + 1.4 
 
 49 
 
 120.2 
 
 115 
 
 239. 
 
 181 
 
 357.8 
 
 247 
 
 476.6 
 
 520 
 
 968 
 
 1180 
 
 2156 
 
 16 
 
 3.2 
 
 50 
 
 122. 
 
 116 
 
 240.8 
 
 182 
 
 359.6 
 
 248 
 
 478.4 
 
 530 
 
 986 
 
 1190 
 
 2174 
 
 15 
 
 5. 
 
 51 
 
 123.8 
 
 117 
 
 242.6 
 
 183 
 
 361.4 
 
 249 
 
 480.2 
 
 540 
 
 1004 
 
 1200 
 
 2192 
 
 -14 
 
 6.8 
 
 52 
 
 125.6 
 
 118 
 
 244.4 
 
 184 
 
 363.2 
 
 250 
 
 482. 
 
 550 
 
 1022 
 
 1210 
 
 2210 
 
 13 
 
 8.6 
 
 53 
 
 127.4 
 
 119 
 
 246.2 
 
 185 
 
 365. 
 
 251 
 
 483.8 
 
 560 
 
 1040 
 
 1220 
 
 2228 
 
 12 
 
 10.4 
 
 54 
 
 129.2 
 
 120 
 
 248. 
 
 186 
 
 366.8 
 
 252 
 
 485.6 
 
 570 
 
 1058 
 
 1230 
 
 2246 
 
 11 
 
 12.2 
 
 55 
 
 131. 
 
 121 
 
 249.8 
 
 187 
 
 368.6 
 
 253 
 
 487.4 
 
 580 
 
 1076 
 
 1240 
 
 2264 
 
 10 
 
 14. 
 
 56 
 
 132.8 
 
 122 
 
 251.6 
 
 188 
 
 370.4 
 
 254 
 
 489.2 
 
 590 
 
 1094 
 
 1250 
 
 2282 
 
 9 
 
 15.8 
 
 57 
 
 134.6 
 
 123 
 
 253.4 
 
 189 
 
 372.2 
 
 255 
 
 491. 
 
 600 
 
 1112 
 
 1260 
 
 2300 
 
 8 
 
 17.6 
 
 58 
 
 136.4 
 
 124 
 
 255.2 
 
 190 
 
 374. 
 
 256 
 
 492.8 
 
 610 
 
 1130 
 
 1270 
 
 2318 
 
 7 
 
 19.4 
 
 59 
 
 138.2 
 
 125 
 
 257. 
 
 191 
 
 375.8 
 
 257 
 
 494.6 
 
 620 
 
 1148 
 
 1280 
 
 2336 
 
 6 
 
 21.2 
 
 60 
 
 140. 
 
 126 
 
 258.8 
 
 192 
 
 377.6 
 
 258 
 
 496.4 
 
 630 
 
 1166 
 
 1290 
 
 2354 
 
 5 
 
 23. 
 
 61 
 
 141.8 
 
 127 
 
 260.6 
 
 193 
 
 379.4 
 
 259 
 
 498.2 
 
 640 
 
 1184 
 
 1300 
 
 2372 
 
 A 
 
 24.8 
 
 62 
 
 143.6 
 
 128 
 
 262.4 
 
 194 
 
 381.2 
 
 260 
 
 500. 
 
 650 
 
 1202 
 
 1310 
 
 2390 
 
 3 
 
 26.6 
 
 63 
 
 145.4 
 
 129 
 
 264.2 
 
 195 
 
 383. 
 
 261 
 
 501.8 
 
 660 
 
 1220 
 
 1320 
 
 2408 
 
 2 
 
 28.4 
 
 64 
 
 147.2 
 
 130 
 
 266. 
 
 196 
 
 384.8 
 
 262 
 
 .503.6 
 
 670 
 
 1238 
 
 1330 
 
 2426 
 
 1 
 
 30.2 
 
 65 
 
 149. 
 
 131 
 
 267.8 
 
 197 
 
 386.6 
 
 263 
 
 505.4 
 
 680 
 
 1256 
 
 1340 
 
 2444 
 
 
 
 32. 
 
 66 
 
 150.8 
 
 132 
 
 269.6 
 
 198 
 
 388.4 
 
 264 
 
 507.2 
 
 690 
 
 1274 
 
 1350 
 
 2462 
 
 + 1 
 
 33.8 
 
 67 
 
 152.6 
 
 133 
 
 271.4 
 
 199 
 
 390.2 
 
 265 
 
 509. 
 
 700 
 
 1292 
 
 13GO 
 
 2480 
 
 2 
 
 35.6 
 
 68 
 
 154.4 
 
 134 
 
 273.2 
 
 200 
 
 392. 
 
 266 
 
 510.8 
 
 710 
 
 1310 
 
 1370 
 
 2498 
 
 3 
 
 37.4 
 
 69 
 
 156.2 
 
 135 
 
 275. 
 
 201 
 
 393.8 
 
 267 
 
 512.6 
 
 720 
 
 1328 
 
 1380 
 
 2516 
 
 4 
 
 39.2 
 
 70 
 
 158. 
 
 136 
 
 276.8 
 
 202 
 
 395.6 
 
 268 
 
 514.4 
 
 730 
 
 1346 
 
 1390 
 
 2534 
 
 5 
 
 41. 
 
 71 
 
 159.8 
 
 137 
 
 278.6 
 
 203 
 
 397.4 
 
 269 
 
 516.2 
 
 740 
 
 1364 
 
 1400 
 
 2552 
 
 6 
 
 42.8 
 
 72 
 
 161.6 
 
 138 
 
 280.4 
 
 204 
 
 399.2 
 
 270 
 
 518. 
 
 750 
 
 1382 
 
 1410 
 
 2570 
 
 7 
 
 44.6 
 
 73 
 
 163.4 
 
 139 
 
 282.2 
 
 205 
 
 401. 
 
 271 
 
 519.8 
 
 760 
 
 1400 
 
 1420 
 
 2588 
 
 8 
 
 46.4 
 
 74 
 
 165.2 
 
 140 
 
 284. 
 
 206 
 
 402.8 
 
 272 
 
 521.6 
 
 770 
 
 1418 
 
 1430 
 
 2606 
 
 9 
 
 48.2 
 
 75 
 
 167. 
 
 141 
 
 285.8 
 
 207 
 
 404.6 
 
 273 
 
 523.4 
 
 780 
 
 1436 
 
 1440 
 
 2624 
 
 10 
 
 50. 
 
 76 
 
 168.8 
 
 142 
 
 287.6 
 
 208 
 
 406.4 
 
 274 
 
 525.2 
 
 790 
 
 1454 
 
 1450 
 
 2642 
 
 11 
 
 51.8 
 
 77 
 
 170.6 
 
 143 
 
 289.4 
 
 209 
 
 408.2 
 
 275 
 
 527. 
 
 800 
 
 1472 
 
 1460 
 
 2660 
 
 12 
 
 53.6 
 
 78 
 
 172 .4 
 
 144 
 
 291.2 
 
 210 
 
 410. 
 
 276 
 
 528.8 
 
 810 
 
 1490 
 
 1470 
 
 2678 
 
 13 
 
 55.4 
 
 79 
 
 174.2 
 
 145 
 
 293. 
 
 211 
 
 411.8 
 
 277 
 
 530.6 
 
 820 
 
 1508 
 
 1480 
 
 2696 
 
 14 
 
 57.2 
 
 80 
 
 176. 
 
 146 
 
 294.8 
 
 212 
 
 413.6 
 
 278 
 
 532.4 
 
 830 
 
 1526 
 
 1490 
 
 2714 
 
 15 
 
 59. 
 
 81 
 
 177.8 
 
 147 
 
 296.6 
 
 213 
 
 415.4 
 
 279 
 
 534.2 
 
 840 
 
 1544 
 
 1500 
 
 2732 
 
 16 
 
 60.8 
 
 82 
 
 179.6 
 
 148 
 
 298.4 
 
 214 
 
 417.2 
 
 280 
 
 536. 
 
 850 
 
 1562 
 
 1510 
 
 2750 
 
 17 
 
 62.6 
 
 83 
 
 181.4 
 
 149 
 
 300.2 
 
 215 
 
 419. 
 
 281 
 
 537.8 
 
 860 
 
 1580 
 
 1520 
 
 2768 
 
 18 
 
 64.4 
 
 84 
 
 183.2 
 
 150 
 
 302. 
 
 216 
 
 420.8 
 
 282 
 
 539.6 
 
 870 
 
 1598 
 
 1530 
 
 2786 
 
 19 
 
 66.2 
 
 85 
 
 185. 
 
 151 
 
 303.8 
 
 217 
 
 422.6 
 
 283 
 
 541.4 
 
 880 
 
 1616 
 
 1540 
 
 2804 
 
 20 
 
 68. 
 
 86 
 
 186.8 
 
 152 
 
 305.6 
 
 218 
 
 424.4 
 
 284 
 
 543.2 
 
 890 
 
 1634 
 
 1550 
 
 2822 
 
 21 
 
 69.8 
 
 87 
 
 188.6 
 
 153 
 
 307.4 
 
 219 
 
 426.2 
 
 285 
 
 545. 
 
 900 
 
 1652 
 
 1600 
 
 2912 
 
 22 
 
 71.6 
 
 88 
 
 190.4 
 
 154 
 
 309.2 
 
 220 
 
 428. 
 
 286 
 
 546.8 
 
 910 
 
 1670 
 
 1650 
 
 3002 
 
 23 
 
 73.4 
 
 89 
 
 192.2 
 
 155 
 
 311. 
 
 221 
 
 429.8 
 
 287 
 
 548.6 
 
 920 
 
 1688 
 
 1700 
 
 3092 
 
 24 
 
 75.2 
 
 90 
 
 194. 
 
 156 
 
 312.8 
 
 222 
 
 431.6 
 
 288, 550.4 
 
 930 
 
 1706 
 
 1750 
 
 3182 
 
 25 77. |l 91 
 
 195.8 157 
 
 314.6 
 
 223 
 
 433.4 289! 552.2 
 
 940 
 
 1724 
 
 1800 
 
 3272 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book.' 
 
394 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 SQUARES, CUBES, SQUARE ROOTS AND CUBE ROOTS OF 
 NUMBERS FROM 0.1 TO 100 
 
 No. 
 
 Square 
 
 Cube 
 
 Sq. 
 Root 
 
 Cube 
 Root 
 
 No. 
 
 Square 
 
 Cube 
 
 Sq. 
 Root 
 
 Cube 
 Root 
 
 0.1 
 
 .01 
 
 .001 
 
 .3162 
 
 .4642 
 
 3.1 
 
 9.61 
 
 29.791 
 
 .761 
 
 .-458 
 
 .15 
 
 .0225 
 
 .0034 
 
 .3873 
 
 .5313 
 
 .2 
 
 10.24 
 
 32.768 
 
 .789 
 
 .474 
 
 .2 
 
 .04 
 
 .008 
 
 .4472 
 
 .5848 
 
 .3 
 
 10.89 
 
 35.937 
 
 .817 
 
 .489 
 
 .25 
 
 .0625 
 
 .0158 
 
 .500 
 
 .6300 
 
 .4 
 
 11.56 
 
 39.304 
 
 .844 
 
 .504 
 
 .3 
 
 .09 
 
 .027 
 
 .5477 
 
 .6694 
 
 .5 
 
 12.25 
 
 42.875 
 
 .871 
 
 .518 
 
 .35 
 
 .1225 
 
 .0429 
 
 .5916 
 
 .7047 
 
 .6 
 
 12.96 
 
 46.656 
 
 .897 
 
 .533 
 
 .4 
 
 .16 
 
 .064 
 
 .6325 
 
 .7368 
 
 .7 
 
 13.69 
 
 50.653 
 
 .924 
 
 .547 
 
 .45 
 
 .2025 
 
 .0911 
 
 .6708 
 
 .7663 
 
 .8 
 
 14.44 
 
 54.872 
 
 .949 
 
 .560 
 
 .5 
 
 .25 
 
 .125 
 
 .7071 
 
 .7937 
 
 .9 
 
 15.21 
 
 59.319 
 
 1.975 
 
 .574 
 
 .55 
 
 .3025 
 
 .1664 
 
 .7416 
 
 .8193 
 
 4. 
 
 16. 
 
 64. 
 
 2. 
 
 .5874 
 
 .6 
 
 .36 
 
 .216 
 
 .7746 
 
 .8434 
 
 .1 
 
 16.81 
 
 68.921 
 
 2.025 
 
 .601 
 
 .65 
 
 .4225 
 
 .2746 
 
 .8062 
 
 .8662 
 
 .2 
 
 17.64 
 
 74.088 
 
 2.049 
 
 .613 
 
 .7 
 
 .49 
 
 .343 
 
 .8367 
 
 .8879 
 
 .3 
 
 18.49 
 
 79.507 
 
 2.074 
 
 .626 
 
 .75 
 
 .5625 
 
 .4219 
 
 .8660 
 
 .9086 
 
 .4 
 
 19.36 
 
 85.184 
 
 2.098 
 
 .639 
 
 .8 
 
 .64 
 
 .512 
 
 .8944 
 
 .9283 
 
 .5 
 
 20.25 
 
 91.125 
 
 2.121 
 
 .651 
 
 .85 
 
 .7225 
 
 .6141 
 
 .9219 
 
 .9473 
 
 .6 
 
 21.16 
 
 97.336 
 
 2.145 
 
 .663 
 
 .9 
 
 .81 
 
 .729 
 
 .9487 
 
 .9655 
 
 .7 
 
 22.09 
 
 103.823 
 
 2.168 
 
 .675 
 
 .95 
 
 .9025 
 
 .8574 
 
 .9747 
 
 .9830 
 
 .8 
 
 23.04 
 
 110.592 
 
 2.191 
 
 .687 
 
 t 
 
 1. 
 
 
 
 1. 
 
 .9 
 
 24.01 
 
 117.649 
 
 2.214 
 
 .698 
 
 .05 
 
 1.1025 
 
 '.158 
 
 '.025 
 
 1.016 
 
 5. 
 
 25. 
 
 125. 
 
 2.2361 
 
 .7100 
 
 .1 
 
 1.21 
 
 .331 
 
 .049 
 
 1.032 
 
 .1 
 
 26.01 
 
 132.651 
 
 2.258 
 
 1.721 
 
 .15 
 
 1.3225 
 
 .521 
 
 .072 
 
 1.048 
 
 .2 
 
 27.04 
 
 140.608 
 
 2.280 
 
 1.732 
 
 .2 
 
 .44 
 
 .728 
 
 .095 
 
 1.063 
 
 .3 
 
 28.09 
 
 148.877 
 
 2.302 
 
 1.744 
 
 .25 
 
 .5625 
 
 .953 
 
 .118 
 
 1.077 
 
 .4 
 
 29.16 
 
 157.464 
 
 2.324 
 
 1.754 
 
 .3 
 
 .69 
 
 2.197 
 
 .140 
 
 1.091 
 
 .5 
 
 30.25 
 
 166.375 
 
 2.345 
 
 1.765 
 
 1.35 
 
 .8225 
 
 2.460 
 
 1.162 
 
 1.105 
 
 .6 
 
 31.36 
 
 175.616 
 
 2.366 
 
 1.776 
 
 1.4 
 
 : .96 
 
 2.744 
 
 1.183 
 
 .119 
 
 .7 
 
 32.49 
 
 185.193 
 
 2.387 
 
 1.786 
 
 1.45 
 
 2.1025 
 
 3.049 
 
 1.204 
 
 .132 
 
 .8 
 
 33.64 
 
 195.112 
 
 2.408 
 
 1.797 
 
 1.5 
 
 2.25 
 
 3.375 
 
 .2247 
 
 .1447 
 
 .9 
 
 34.81 
 
 205.379 
 
 2.429 
 
 1.807 
 
 1.55 
 
 2.4025 
 
 3.724 
 
 .245 
 
 .157 
 
 6. 
 
 36. 
 
 216. 
 
 2.4495 
 
 1.8171 
 
 1.6 
 
 2.56 
 
 4.096 
 
 .265 
 
 .170 
 
 .1 
 
 37.21 
 
 226.981 
 
 2.470 
 
 .827 
 
 1.65 
 
 2.7225 
 
 4.492 
 
 .285 
 
 .182 
 
 .2 
 
 38.44 
 
 238.328 
 
 2.490 
 
 .837 
 
 1.7 
 
 2.89 
 
 4.913 
 
 .304 
 
 .193 
 
 .3 
 
 39.69 
 
 250.047 
 
 2.510 
 
 .847 
 
 1.75 
 
 3.0625 
 
 5.359 
 
 .323 
 
 .205 
 
 .4 
 
 40.96 
 
 262.144 
 
 2.530 
 
 .857 
 
 1.8 
 
 3.24 
 
 5.832 
 
 .342 
 
 .216 
 
 .5 
 
 42.25 
 
 274.625 
 
 2.550 
 
 .866 
 
 1.85 
 
 3.4225 
 
 6.332 
 
 .360 
 
 .228 
 
 .6 
 
 43.56 
 
 287.496 
 
 2.569 
 
 .876 
 
 1.9 
 
 3.61 
 
 6.859 
 
 .378 
 
 .239 
 
 .7 
 
 44.89 
 
 300.763 
 
 2.588 
 
 .885 
 
 1.95 
 
 3.8025 
 
 7.415 
 
 .396 
 
 .249 
 
 .8 
 
 46.24 
 
 314.432 
 
 2.608 
 
 .895 
 
 2. 
 
 4. 
 
 8. 
 
 .4142 
 
 .2599 
 
 .9 
 
 47.61 
 
 328.509 
 
 2.627 
 
 .904 
 
 .1 
 
 4.41 
 
 9.261 
 
 .449 
 
 1.281 
 
 7. 
 
 49. 
 
 343. 
 
 2.6458 
 
 .9129 
 
 .2 
 
 4.84 
 
 10.648 
 
 1.483 
 
 1.301 
 
 .1 
 
 50.41 
 
 357.911 
 
 2.665 
 
 .922 
 
 .3 
 
 5.29 
 
 12.167 
 
 1.517 
 
 1.320 
 
 .2 
 
 51.84 
 
 373.248 
 
 2.683 
 
 .931 
 
 .4 
 
 5.76 
 
 13.824 
 
 1.549 
 
 1.389 
 
 .3 
 
 53.29 
 
 389.017 
 
 2.702 
 
 .940 
 
 .5 
 
 6.25 
 
 15.625 
 
 1.581 
 
 1.357 
 
 .4 
 
 54.76 
 
 405.224 
 
 2.720 
 
 .949 
 
 .6 
 
 6.76 
 
 17.576 
 
 1.612 
 
 1.375 
 
 .5 
 
 56.25 
 
 421.875 
 
 2.739 
 
 .957 
 
 .7 
 
 7.29 
 
 19.683 
 
 1.643 
 
 1.392 
 
 .6 
 
 57.76 
 
 438.976 
 
 2.757 
 
 1.966 
 
 .8 
 
 7.84 
 
 21.952 
 
 1.673 
 
 1.409 
 
 .7 
 
 59.29 
 
 456.533 
 
 2.775 
 
 1.975 
 
 .9 
 
 8.41 
 
 24.389 
 
 1.703 
 
 1.426 
 
 .8 
 
 60.84 
 
 474.552 
 
 2.793 
 
 1.983 
 
 3. 
 
 9. 
 
 27. 
 
 1.7321 
 
 1.4422 
 
 .9 
 
 62.41 
 
 493.039 
 
 2.811 
 
 1.992 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 395 
 
 No. 
 
 Square 
 
 Cube 
 
 Sq. 
 Root 
 
 Cube 
 Root 
 
 No. 
 
 Sq. 
 
 Cube 
 
 Sq. 
 Root 
 
 Cube 
 Root 
 
 8. 
 
 64. 
 
 512. 
 
 2.8284 
 
 2. 
 
 45 
 
 2025 
 
 91125 
 
 6.7082 
 
 3.5569 
 
 .1 
 
 65.61 
 
 531.441 
 
 2.846 
 
 2.008 
 
 46 
 
 2116 
 
 97336 
 
 6.7823 
 
 3.5830 
 
 .2 
 
 67.24 
 
 551.368 
 
 2.864 
 
 2.017 
 
 47 
 
 2209 
 
 103823 
 
 6.8557 
 
 3.6088 
 
 .3 
 
 68.89 
 
 571.787 
 
 2.881 
 
 2.025 
 
 48 
 
 2304 
 
 110592 
 
 6.9282 
 
 3.6342 
 
 A 
 
 70.56 
 
 592.704 
 
 2.898 
 
 2.033 
 
 49 
 
 2401 
 
 117649 
 
 7. 
 
 3.6593 
 
 .5 
 
 72.25 
 
 614.125 
 
 2.915 
 
 2.041 
 
 50 
 
 2500 
 
 125000 
 
 7.0711 
 
 3.6840 
 
 .6 
 
 73.96 
 
 636.056 
 
 2.933 
 
 2.049 
 
 51 
 
 2601 
 
 132651 
 
 7.1414 
 
 3.7084 
 
 .7 
 
 75.69 
 
 658.503 
 
 2.950 
 
 2.057 
 
 52 
 
 2704 
 
 140608 
 
 7.2111 
 
 3.7325 
 
 .8 
 
 77.44 
 
 681.472 
 
 2.966 
 
 2.065 
 
 53 
 
 2809 
 
 148877 
 
 7.2801 
 
 3.7563 
 
 .9 
 
 79.21 
 
 704.969 
 
 2.983 
 
 2.072 
 
 54 
 
 2916 
 
 157464 
 
 7.3485 
 
 3.7798 
 
 9. 
 
 81. 
 
 729. 
 
 3. 
 
 2.0801 
 
 55 
 
 3025 
 
 166375 
 
 7.4162 
 
 3.8030 
 
 .1 
 
 82.81 
 
 753.571 
 
 3.017 
 
 2.088 
 
 56 
 
 3136 
 
 175616 
 
 7.4833 
 
 3.8259 
 
 .2 
 
 84.64 
 
 778.688 
 
 3.033 
 
 2.095 
 
 57 
 
 3249 
 
 185193 
 
 7.5498 
 
 3.8485 
 
 .3 
 
 86.49 
 
 804.357 
 
 3.050 
 
 2.103 
 
 58 
 
 3364 
 
 195112 
 
 7.6158 
 
 3.8709 
 
 .4 
 
 88.36 
 
 830.584 
 
 3.066 
 
 2.110 
 
 59 
 
 3481 
 
 205379 
 
 7.6811 
 
 3.8930 
 
 .5 
 
 90.25 
 
 857.375 
 
 3.082 
 
 2.118 
 
 60 
 
 3600 
 
 216000 
 
 7.7460 
 
 3.9149 
 
 .6 
 
 92.16 
 
 884.736 
 
 3.098 
 
 2.125 
 
 61 
 
 3721 
 
 22G981 
 
 7.8102 
 
 3.9365 
 
 .7 
 
 94.09 
 
 912.673 
 
 3.114 
 
 2.133 
 
 62 
 
 3844 
 
 238328 
 
 7.8740 
 
 3.9579 
 
 .8 
 
 96.04 
 
 941.192 
 
 3.130 
 
 2.140 
 
 63. 
 
 3969 
 
 250047 
 
 7.9373 
 
 3.9791 
 
 .9 
 
 98.01 
 
 970.299 
 
 3.146 
 
 2.147 
 
 64 
 
 4096 
 
 262144 
 
 8. 
 
 4. 
 
 10 
 
 100 
 
 1000 
 
 3.1623 
 
 2.1544 
 
 65 
 
 4225 
 
 274625 
 
 8.0623 
 
 4.0207 
 
 11 
 
 121 
 
 1331 
 
 3.3166 
 
 2.2240 
 
 66 
 
 4356 
 
 287496 
 
 8.1240 
 
 4.0412 
 
 12 
 
 144 
 
 1728 
 
 3.4641 
 
 2.2894 
 
 67 
 
 4489 
 
 300763 
 
 8.1854 
 
 4.0615 
 
 13 
 
 169 
 
 2197 
 
 3.6056 
 
 2.3513 
 
 68 
 
 4624 
 
 314432 
 
 8.2462 
 
 4.0817 
 
 14 
 
 196 
 
 2744 
 
 3.7417 
 
 2.4101 
 
 69 
 
 4761 
 
 328509 
 
 8.3066 
 
 4.1016 
 
 15 
 
 225 
 
 3375 
 
 3.8730 
 
 2.4662 
 
 70 
 
 4900 
 
 343000 
 
 8.3666 
 
 4.1213 
 
 16 
 
 256 
 
 4096 
 
 4. 
 
 2.5198 
 
 71 
 
 5041 
 
 357911 
 
 8.4261 
 
 4.1408 
 
 17 
 
 289 
 
 4913 
 
 4.1231 
 
 2.5713 
 
 72 
 
 5184 
 
 373248 
 
 8.4853 
 
 4.1602 
 
 18 
 
 324 
 
 5832 
 
 4.2426 
 
 2.6207 
 
 73 
 
 5329 
 
 389017 
 
 8.5440 
 
 4.1793 
 
 19 
 
 361 
 
 6859 
 
 4.3589 
 
 2.6684 
 
 74 
 
 5476 
 
 405224 
 
 8.6023 
 
 4.1983 
 
 20 
 
 400 
 
 8000 
 
 4.4721 
 
 2.7144 
 
 75 
 
 5625 
 
 421875 
 
 8.6603 
 
 4.2172 
 
 21 
 
 441 
 
 9261 
 
 4.5826 
 
 2.7589 
 
 76 
 
 5776 
 
 438976 
 
 8.7178 
 
 4.2358 
 
 22 
 
 484 
 
 10648 
 
 4.6904 
 
 2.8020 
 
 77 
 
 5929 
 
 456533 
 
 8.7750 
 
 4.2543 
 
 23 
 
 529 
 
 12167 
 
 4.7958 
 
 2.8439 
 
 78 
 
 6084 
 
 474552 
 
 8.8318 
 
 4.2727 
 
 24 
 
 576 
 
 13824 
 
 4.8990 
 
 2.8845 
 
 79 
 
 6241 
 
 493039 
 
 8.8882 
 
 4.2908 
 
 25 
 
 625 
 
 15625 
 
 5. 
 
 2.9240 
 
 80 
 
 6400 
 
 512000 
 
 8.9443 
 
 4.3089 
 
 26 
 
 676 
 
 17576 
 
 5.0990 
 
 2.9625 
 
 81 
 
 6561 
 
 531441 
 
 9. 
 
 4.3267 
 
 27 
 
 729 
 
 19683 
 
 5.1962 
 
 3. 
 
 82 
 
 6724 
 
 551368 
 
 9.0554 
 
 4.3445 
 
 28 
 
 784 
 
 21952 
 
 5.2915 
 
 3.0366 
 
 83 
 
 6889 
 
 571787 
 
 9.1104 
 
 4.3621 
 
 29 
 
 841 
 
 24389 
 
 5.3852 
 
 3.0723 
 
 84 
 
 7056 
 
 592704 
 
 9.1652 
 
 4.3795 
 
 30 
 
 900 
 
 27000 
 
 5.4772 
 
 3.1072 
 
 85 
 
 7225 
 
 614125 
 
 1 9.2195 
 
 4.3968 
 
 31 
 
 961 
 
 29791 
 
 5.5678 
 
 3.1414 
 
 86 
 
 7396 
 
 636056 
 
 9.2736 
 
 4.4140 
 
 32 
 
 1024 
 
 32768 
 
 5.6569 
 
 3.1748 
 
 87 
 
 7569 
 
 658503 
 
 9.3276 
 
 4.4310 
 
 33 
 
 1089 
 
 35937 
 
 5.7446 
 
 3.2075 
 
 88 
 
 7744 
 
 681472 
 
 9.3808 
 
 4.4480 
 
 34 
 
 1156 
 
 39304 
 
 5.8310 
 
 3.2396 
 
 89 
 
 7921 
 
 704969 
 
 9.4340 
 
 4.4647 
 
 35 
 
 1225 
 
 42875 
 
 5.9161 
 
 3.2711 
 
 90 
 
 8100 
 
 729000 
 
 9.4868 
 
 4.4814 
 
 36 
 
 1296 
 
 46656 
 
 6. 
 
 3.3019 
 
 91 
 
 8281 
 
 753571 
 
 9.5394 
 
 4.4979 
 
 37 
 
 1369 
 
 50653 
 
 6.0828 
 
 3.3322 
 
 92 
 
 8464 
 
 778688 
 
 9.5917 
 
 4.5144 
 
 38 
 
 1444 
 
 54872 
 
 6.1644 
 
 3.3620 
 
 93 
 
 8649 
 
 804357 
 
 9.6437 
 
 4.5307 
 
 39 
 
 1521 
 
 59319 
 
 6.2450 
 
 3.3912 
 
 94 
 
 8836 
 
 830584 
 
 9.6954 
 
 4.5468 
 
 40 
 
 1600 
 
 64000 
 
 6.3246 
 
 3.4200 
 
 95 
 
 9025 
 
 857375 
 
 9.7468 
 
 4.5629 
 
 41 
 
 1681 
 
 68921 
 
 6.4031 
 
 3.4482 
 
 96 
 
 9216 
 
 884736 
 
 9.7980 
 
 4.5789 
 
 42 
 
 1764 
 
 74088 
 
 6.4807 
 
 3.4760 
 
 97 
 
 9409 
 
 912673 
 
 9.8489 
 
 4.5947 
 
 43 
 
 1849 
 
 79507 
 
 6.5574 
 
 3.5034 
 
 98 
 
 9604 
 
 941192 
 
 9.8995 
 
 4.6104 
 
 44 
 
 1936 
 
 85184 
 
 6.6332 
 
 3.5303 
 
 99 
 
 9801 
 
 970299 
 
 9.9499 
 
 4.6261 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
396 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 COMMON FRACTIONS AND THEIR EQUIVALENTS IN DECIMAL 
 INCHES AND MILLIMETERS 
 
 Fraction 
 
 Inches 
 
 Milli- 
 meters 
 
 Fraction 
 
 Inches 
 
 Milli- 
 meters 
 
 1/64 
 
 .0156 
 
 .397 
 
 3 %4 
 
 .5156 
 
 13.10 
 
 V32 
 
 .0313 
 
 .79 
 
 17 /32 
 
 .5313 
 
 13.50 
 
 %4 
 
 .0469 
 
 1.19 
 
 S %4 
 
 .5469 
 
 13.89 
 
 *4 %2 
 
 .0625 
 
 1.59 
 
 %e J %a 
 
 .5625 
 
 14.29 
 
 %4 
 
 .0781 
 
 1.98 
 
 3 %4 
 
 .5781 
 
 14.69 
 
 %2 
 %4 
 
 .0938 
 .1094 
 
 2.38 
 
 2.78 
 
 19 /32 
 3 %4 
 
 .5938 
 .6094 
 
 15.09 
 15.48 
 
 % y 32 
 
 .1250 
 
 3.18 
 
 % 2 %2 
 
 .6250 
 
 15.88 
 
 %4 
 
 .1406 
 
 3.57 
 
 4 V64 
 
 .6406 
 
 16.28 
 
 %2 
 
 .1563 
 
 3^97 
 
 21 /32 
 
 .6563 
 
 16.67 
 
 ^e* 
 
 .1719 
 
 4.37 
 
 4 %4 
 
 .6719 
 
 17.07 
 
 %6 %2 
 
 .1875 
 
 4.76 
 
 !%e 22 /32 
 
 .6875 
 
 17.47 
 
 13 /64 
 
 .2031 
 
 5.16 
 
 45 /64 
 
 .7031 
 
 17.86 
 
 7 /32 
 
 .2188 
 
 5.56 
 
 2 %2 
 
 .7188 
 
 18.26 
 
 15 /64 
 
 .2344 
 
 5.95 
 
 4 %4 
 
 .7344 
 
 18.66 
 
 H % 2 
 
 .2500 
 
 6.35 
 
 % 24 /32 
 
 .7500 
 
 19.01 
 
 17 /64 
 
 .2656 
 
 6.75 
 
 4 %4 
 
 .7656 
 
 19.45 
 
 %2 
 
 .2813 
 
 7.15 
 
 2 %2 
 
 .7813 
 
 19.85 
 
 1P /64 
 
 .2969 
 
 7.54 
 
 5 %4 
 
 .7969 
 
 20.25 
 
 5 /16 10 /32 
 
 .3125 
 
 7.94 
 
 13 A 2 %2 
 
 .8125 
 
 20.64 
 
 21 /64 
 
 .3281 
 
 8.34 
 
 5 %4 
 
 .8281 
 
 21.04 
 
 1 V32 
 
 .3438 
 
 8.73 
 
 2 %2 
 
 .8438 
 
 21.44 
 
 2 %4 
 
 .3594 
 
 9.13 
 
 G %4 
 
 .8594 
 
 21.83 
 
 % 1%2 
 
 .3750 
 
 9.53 
 
 % 28 /83 
 
 .8750 
 
 22.23 
 
 25 /64 
 
 .3906 
 
 9.92 
 
 5 %4 
 
 .8906 
 
 22.63 
 
 13 /32 
 
 .4063 
 
 10.32 
 
 2 %2 
 
 .9063 
 
 23.02 
 
 2 %4 
 
 .4219 
 
 10.72 
 
 5 %4 
 
 .9219 
 
 23.42 
 
 Vie i% 2 
 
 .4375 
 
 11.12 
 
 15 /ie 3 %2 
 
 .9375 
 
 23.82 
 
 2 %4 
 
 .4531 
 
 * 11.51 
 
 61 /64 
 
 .9531 
 
 24.22 
 
 *%2 
 
 .4688 
 
 11.91 
 
 3 V32 
 
 .9688 
 
 24.61 
 
 3 V'e4 
 
 .4844 
 
 12.31 
 
 6 %4 
 
 .9844 
 
 25.01 
 
 % 16 /32 
 
 .5000 
 
 12.70 
 
 1 8 %2 
 
 1 . 0000 
 
 25 .41 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 397 
 
 CIRCUMFERENCE AND AREAS OF CIRCLES 
 
 Diam. 
 
 CIrcum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 %4 
 
 .04909 
 
 .00019 
 
 3V2 
 
 7.8540 
 
 4.9087 
 
 6% 
 
 20.813 
 
 34.472 
 
 $* 
 
 .09818 
 
 .00077 
 
 %6 
 
 8.0503 
 
 5.1572 
 
 % 
 
 21.206 
 
 35.785 
 
 %4 
 
 .14726 
 
 .00173 
 
 % 
 
 8.2467 
 
 5.4119 
 
 % 
 
 21.598 
 
 37.122 
 
 %e 
 
 . 19635 
 
 .00307 
 
 *Me 
 
 8.4430 
 
 5.6727 
 
 7. 
 
 21.991 
 
 38.485 
 
 %2 
 
 .29452 
 
 .00690 
 
 % 
 
 8.6394 
 
 5.9396 
 
 Vs 
 
 22.384 
 
 39.871 
 
 % 
 
 .39270 
 
 .01227 
 
 13 Ao 
 
 8.8357 
 
 6.2126 
 
 % 
 
 22.776 
 
 41.282 
 
 %2 
 
 .49087 
 
 .01917 
 
 % 
 
 9.0321 
 
 6.4918 
 
 % 
 
 23.169 
 
 42.718 
 
 8 /16 
 
 .58905 
 
 .02761 
 
 15 Ae 
 
 9.2284 
 
 6.7771 
 
 2 
 
 23.562 
 
 44.179 
 
 %a 
 
 .68722 
 
 .03758 
 
 
 
 
 % 
 
 23.955 
 
 45.664 
 
 
 
 
 3. 
 
 9.4248 
 
 7.0686 
 
 % 
 
 24.347 
 
 47.173 
 
 ^4 
 
 .78540 
 
 .04909 
 
 Me 
 
 9.6211 
 
 7.3662 
 
 Vs 
 
 24.740 
 
 48.707 
 
 %2 
 
 .88357 
 
 .06213 
 
 Vs 
 
 9.8175 
 
 7.6699 
 
 8. 
 
 25.133 
 
 50.265 
 
 6 /ie 
 
 .98175 
 
 .07670 
 
 8 Ae 
 
 10.014 
 
 7.9798 
 
 % 
 
 25.525 
 
 51.849 
 
 l %a 
 
 1.0799 
 
 .09281 
 
 M 
 
 10.210 
 
 8.2958 
 
 $ 
 
 25.918 
 
 53.456 
 
 % 
 
 1.1781 
 
 .11045 
 
 5 Ae 
 
 10.407 
 
 8.6179 
 
 % 
 
 26.311 
 
 55.088 
 
 13 /S2 
 
 1.2763 
 
 .12962 
 
 % 
 
 10.603 
 
 8.9462 
 
 2 
 
 26.704 
 
 56.745 
 
 %e 
 
 1.3744 
 
 .15033 
 
 Me 
 
 10.799 
 
 9.2806 
 
 % 
 
 27.096 
 
 58.426 
 
 15 /S2 
 
 1.4726 
 
 .17257 
 
 V2 
 
 10.996 
 
 9.6211 
 
 8 /4 
 
 27.489 
 
 60.132 
 
 
 
 
 9 Ae 
 
 11.192 
 
 9.9678 
 
 % 
 
 27.882 
 
 61.862 
 
 ft 
 
 1.5708 
 
 .19635 
 
 % 
 
 11.388 
 
 10.321 
 
 9. 
 
 28.274 
 
 63.617 
 
 17 /32 
 
 1.6690 
 
 .22166 
 
 !Me 
 
 11.585 
 
 10.680 
 
 Vs 
 
 28.667 
 
 65.397 
 
 9 /16 
 
 1.7671 
 
 .24850 
 
 8 /4 
 
 11.781 
 
 11.045 
 
 % 
 
 29.060 
 
 67.201 
 
 18 /32 
 
 1.8653 
 
 .27688 
 
 1%8 
 
 11.977 
 
 11.416 
 
 % 
 
 29.452 
 
 69.029 
 
 % 
 
 1.9635 
 
 .30680 
 
 7 /8 
 
 12.174 
 
 11.793 
 
 V2 
 
 29.845 
 
 70.882 
 
 21/32 
 
 2.0617 
 
 .33824 
 
 15 Ae 
 
 12.370 
 
 12.177 
 
 
 30.238 
 
 72.760 
 
 !Vie 
 
 2.1598 
 
 .37122 
 
 4. 
 
 12.566 
 
 12.566 
 
 % 
 
 30.631 
 
 74.662 
 
 2 %2 
 
 2.2580 
 
 .40574 
 
 Me 
 
 12.763 
 
 12.962 
 
 % 
 
 31.023 
 
 76.589 
 
 
 
 
 % 
 
 12.959 
 
 13.364 
 
 10. 
 
 31.416 
 
 78.540 
 
 3 /4 
 
 2.3562 
 
 .44179 
 
 8 /16 
 
 13.155 
 
 13.772 
 
 % 
 
 31.809 
 
 80.516 
 
 35 /32 
 
 2.4544 
 
 .47937 
 
 M 
 
 13.352 
 
 14.186 
 
 J /4 
 
 32.201 
 
 82.516 
 
 18 Ae 
 
 2.5525 
 
 .51849 
 
 5 Ae 
 
 13.548 
 
 14.607 
 
 % 
 
 32.594 
 
 84.541 
 
 27 /82 
 
 2.6507 
 
 .55914 
 
 % 
 
 13.744 
 
 15.033 
 
 % 
 
 32.987 
 
 86.590 
 
 % 
 
 2.7489 
 
 .60132 
 
 7 Ae 
 
 13.941 
 
 15.466 
 
 % 
 
 33.379 
 
 88.664 
 
 2 %2 
 
 2.8471 
 
 .64504 
 
 V2 
 
 14.137 
 
 15.904 
 
 % 
 
 33.772 
 
 90.763 
 
 15 /16 
 
 2.9452 
 
 .69029 
 
 8 Ae 
 
 14.334 
 
 16.349 
 
 7 /8 
 
 34.165 
 
 92.886 
 
 V32 
 
 3.0434 
 
 .73708 
 
 % 
 
 14.530 
 
 16.800 
 
 11. 
 
 34.558 
 
 95.033 
 
 
 
 
 iVie 
 
 14.726 
 
 17.257 
 
 Vs 
 
 34.950 
 
 97.205 
 
 1. 
 
 3.1416 
 
 .7854 
 
 % 
 
 14.923 
 
 17.721 
 
 M 
 
 35.343 
 
 99.402 
 
 %6 
 
 3.3379 
 
 .8866 
 
 18 Ao 
 
 15.119 
 
 18.190 
 
 % 
 
 35.736 
 
 101.62 
 
 Vs 
 
 3.5343 
 
 .9940 
 
 % 
 
 15.315 
 
 18.665 
 
 V2 
 
 36.128 
 
 103.87 
 
 8 Ae 
 
 3.7306 
 
 1 . 1075 
 
 15 /16 
 
 15.512 
 
 19.147 
 
 % 
 
 36.521 
 
 106.14 
 
 % 
 
 3.9270 
 
 1.2272 
 
 5. 
 
 15.708 
 
 19.635 
 
 % 
 
 36.914 
 
 108.43 
 
 B Ae 
 
 4.1233 
 
 1.3530 
 
 Me 
 
 15.904 
 
 20.129 
 
 7 /8 
 
 37.306 
 
 110.75 
 
 % 
 
 4.3197 
 
 1.4849 
 
 % 
 
 16.101 
 
 20.629 
 
 12. 
 
 37.699 
 
 113.10 
 
 7 Ae 
 
 4.5160 
 
 1.6230 
 
 8 /ie 
 
 16.297 
 
 21.135 
 
 Vs 
 
 38.092 
 
 115.47 
 
 v 2 
 
 4.7124 
 
 1.7671 
 
 % 
 
 16.493 
 
 21.648 
 
 w 
 
 .38.485 
 
 117.86 
 
 Ae 
 
 4.9087 
 
 1.9175 
 
 6 Ao 
 
 16.690 
 
 22.166 
 
 % 
 
 38.877 
 
 120.28 
 
 % 
 
 5.1051 
 
 2.0739 
 
 % 
 
 16.886 
 
 22.691 
 
 V2 
 
 39.270 
 
 122.72 
 
 Wie 
 
 5.3014 
 
 2.2365 
 
 7 Ae 
 
 17.082 
 
 23.221 
 
 
 39.663 
 
 125.19 
 
 % 
 
 5.4978 
 
 2.4053 
 
 V 2 
 
 17.279 
 
 23.758 
 
 
 40.055 
 
 127.68 
 
 18 Ae 
 
 5.6941 
 
 2.5802 
 
 9 Ae 
 
 17.475 
 
 24.301 
 
 % 
 
 40.448 
 
 130.19 
 
 7 /8 
 
 5.8905 
 
 2.7612 
 
 % 
 
 17.671 
 
 24.850 
 
 13. 
 
 40.841 
 
 132.73 
 
 15 A6 
 
 6.0868 
 
 2.9483 
 
 H4e 
 
 17.868 
 
 25.406 
 
 Vs 
 
 41.233 
 
 135.30 
 
 
 
 
 8 /4 
 
 18.064 
 
 25.967 
 
 5? 
 
 41.626 
 
 137.89 
 
 2. 
 
 6.2832 
 
 3.1416 
 
 18 Ae 
 
 18.261 
 
 26.535 
 
 % 
 
 42.019 
 
 140.50 
 
 Me 
 
 6.4795 
 
 3.3410 
 
 % 
 
 18.457 
 
 27.109 
 
 Y2 
 
 42.412 
 
 143.14 
 
 Vs 
 
 6.6759 
 
 3.5466 
 
 15 Ae 
 
 18.653 
 
 27.688 
 
 % 
 
 42.804 
 
 145.80 
 
 8 Ae 
 
 6.8722 
 
 3.7583 
 
 6. 
 
 18.850 
 
 28.274 
 
 % 
 
 43.197 
 
 148.49 
 
 % 
 
 7.0686 
 
 3.9761 
 
 % 
 
 19.242 
 
 29.465 
 
 % 
 
 43.590 
 
 LSI. 20 
 
 B Ae 
 
 7.2649 
 
 4.2000 
 
 % 
 
 19.635 
 
 30.680 
 
 14. 
 
 43.982 
 
 153.94 
 
 % 
 
 7.4613 
 
 4.4301 
 
 % 
 
 20.028 
 
 31.919 
 
 Vs 
 
 44.375 
 
 156.70 
 
 Me 
 
 7.6576 
 
 4.6664 
 
 2 
 
 20.420 
 
 33.183 
 
 V4 
 
 44.768 
 
 159.48 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
398 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Diain. 
 
 Clrcuin. 
 
 Area 
 
 Diarn. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 14/8 
 
 45.160 
 
 162.30 
 
 22y 4 
 
 69.900 
 
 388.82 
 
 30Vs 
 
 94.640 
 
 712.76 
 
 
 45.553 
 
 165.13 
 
 % 
 
 70.293 
 
 393.20 
 
 y* 
 
 95.033 
 
 718.69 
 
 % 
 
 45.946 
 
 167.99 
 
 Va 
 
 70.686 
 
 397.61 
 
 % 
 
 95.426 
 
 724.64 
 
 % 
 
 46.338 
 
 170.87 
 
 
 71.079 
 
 402.04 
 
 y 2 
 
 95.819 
 
 730.62 
 
 % 
 
 46.731 
 
 173.78 
 
 
 71.471 
 
 406.49 
 
 % 
 
 96.211 
 
 736.62 
 
 15. 
 
 47.124 
 
 176.71 
 
 % 
 
 71.864 
 
 410.97 
 
 % 
 
 96.604 
 
 742.64 
 
 
 47.517 
 
 179.67 
 
 23. 
 
 72.257 
 
 415.48 
 
 % 
 
 96.997 
 
 748.69 
 
 
 47.909 
 
 182.65 
 
 Vs 
 
 72.649 
 
 420.00 
 
 31. 
 
 97.389 
 
 754.77 
 
 
 48.302 
 
 185.66 
 
 % 
 
 73.042 
 
 424.56 
 
 K 
 
 97.782 
 
 760.87 
 
 
 48.695 
 
 188.69 
 
 % 
 
 73.435 
 
 429.13 
 
 % 
 
 98.175 
 
 766.99 
 
 
 49.087 
 
 191.75 
 
 
 73.827 
 
 433.74 
 
 % 
 
 98.567 
 
 773.14 
 
 
 49.480 
 
 194.83 
 
 5 8 
 
 74.220 
 
 438.36 
 
 V2 
 
 98.960 
 
 779.31 
 
 % 
 
 49.873 
 
 197.93 
 
 % 
 
 74.613 
 
 443.01 
 
 % 
 
 99.353 
 
 785.51 
 
 16. 
 
 50.265 
 
 201.06 
 
 % 
 
 75.006 
 
 447.69 
 
 % 
 
 99.746 
 
 791.73 
 
 % 
 
 50.658 
 
 204.22 
 
 24. 
 
 75.398 
 
 452.39 
 
 % 
 
 100.138 
 
 797.98 
 
 4 
 
 51.051 
 
 207.39 
 
 Vs 
 
 75.791 
 
 457.11 
 
 32. 
 
 100.531 
 
 804.25 
 
 % 
 
 51.444 
 
 210.60 
 
 V* 
 
 76.184 
 
 461.86 
 
 tt 
 
 100.924 
 
 810.54 
 
 % 
 
 51.836 
 
 213.82 
 
 % 
 
 76.576 
 
 466.64 
 
 y4 
 
 101.316 
 
 816.86 
 
 
 52.229 
 
 217.08 
 
 Vz 
 
 76.969 
 
 471.44 
 
 % 
 
 101.709 
 
 823.21 
 
 
 52.622 
 
 220.35 
 
 % 
 
 77.362 
 
 476.26 
 
 y 2 
 
 102.102 
 
 829.58 
 
 7 /8 
 
 53.014 
 
 223.65 
 
 % 
 
 77.754 
 
 481.11 
 
 % 
 
 102.494 
 
 835.97 
 
 17. 
 
 53.407 
 
 226.98 
 
 % 
 
 78.147 
 
 485.98 
 
 % 
 
 102.887 
 
 842.39 
 
 Vs 
 
 53.800 
 
 230.33 
 
 25. 
 
 78.540 
 
 490.87 
 
 % 
 
 103.280 
 
 848.83 
 
 $ 
 
 54.192 
 
 233.71 
 
 Vs 
 
 78.933 
 
 495.79 
 
 33. 
 
 103.673 
 
 855.30 
 
 % 
 
 54.585 
 
 237.10 
 
 4 
 
 79.325 
 
 500.74 
 
 VH 
 
 104.065 
 
 861.79 
 
 V'a 
 
 54.978 
 
 240.53 
 
 % 
 
 79.718 
 
 505.71 
 
 M 
 
 104.458 
 
 868.31 
 
 
 55.371 
 
 243.98 
 
 2 
 
 80.111 
 
 510.71 
 
 % 
 
 104.851 
 
 874.85 
 
 |i1 
 
 55.763 
 
 247.45 
 
 % 
 
 80.503 
 
 515.72 
 
 y 2 
 
 105.243 
 
 881.41 
 
 % 
 
 56.156 
 
 250.95 
 
 % 
 
 80.896 
 
 520.77 
 
 % 
 
 105.636 
 
 888.00 
 
 18. 
 
 56.549 
 
 254.47 
 
 % 
 
 81.289 
 
 525.84 
 
 % 
 
 106.029 
 
 894.62 
 
 ys 
 
 56.941 
 
 258.02 
 
 26. 
 
 81.681 
 
 530.93 
 
 % 
 
 106.421 
 
 901.26 
 
 2 
 
 57.334 
 
 261.59 
 
 y 
 
 82.074 
 
 536.05 
 
 34. 
 
 106.814 
 
 907.92 
 
 % 
 
 57.727 
 
 265.18 
 
 % 
 
 82.467 
 
 541.19 
 
 tt 
 
 107.207 
 
 914.61 
 
 Vz 
 
 58.119 
 
 268.80 
 
 % 
 
 82.860 
 
 546.35 
 
 y* 
 
 107.600 
 
 921.32 
 
 % 
 
 58.512 
 
 272.45 
 
 % 
 
 83.252 
 
 551.55 
 
 % 
 
 107.992 
 
 928.06 
 
 % 
 
 58.905 
 
 276.12 
 
 
 83.645 
 
 556.76 
 
 Vz 
 
 108.385 
 
 934.82 
 
 7 /8 
 
 59.298 
 
 279.81 
 
 
 84.038 
 
 562.00 
 
 % 
 
 108.778 
 
 941.61 
 
 19. 
 
 59.690 
 
 283.53 
 
 % 
 
 84.430 
 
 567.27 
 
 % 
 
 109.170 
 
 948.42 
 
 % 
 
 60.083 
 
 287.27 
 
 27. 
 
 84.823 
 
 572.56 
 
 % 
 
 109.563 
 
 955.25 
 
 2 
 
 60.476 
 
 291.04 
 
 Vs 
 
 85.216 
 
 577.87 
 
 35. 
 
 109.956 
 
 962.11 
 
 % 
 
 60.868 
 
 294.83 
 
 % 
 
 85.608 
 
 583.21 
 
 ys 
 
 110.348 
 
 969.00 
 
 3 
 
 61.261 
 
 298.65 
 
 % 
 
 86.001 
 
 588.57 
 
 y 4 
 
 110.741 
 
 975.91 
 
 
 61.654 
 
 302.49 
 
 Vz 
 
 86.394 
 
 593.96 
 
 % 
 
 111.134 
 
 982.84 
 
 
 62.046 
 
 306.35 
 
 % 
 
 86.786 
 
 599.37 
 
 y 2 
 
 111.527 
 
 989.80 
 
 % 
 
 62.439 
 
 310.24 
 
 % 
 
 87.179 
 
 604.81 
 
 % 
 
 111.919 
 
 996.78 
 
 30. 
 
 62.832 
 
 314.16 
 
 7 /8 
 
 87.572 
 
 610.27 
 
 % 
 
 112.312 
 
 1003.8 
 
 ^ 
 
 63.225 
 
 318.10 
 
 28. 
 
 87.965 
 
 615.75 
 
 % 
 
 112.705 
 
 1010.8 
 
 $ 
 
 63.617 
 
 322.06 
 
 s 
 
 88.357 
 
 621.26 
 
 36. 
 
 113.097 
 
 1017.9 
 
 % 
 
 64.010 
 
 326.05 
 
 % 
 
 88.750 
 
 626.80 
 
 ys 
 
 113.490 
 
 1025.0 
 
 i 
 
 64.403 
 64.795 
 
 330.06 
 334.10 
 
 % 
 
 Va 
 
 89.143 
 89.535 
 
 632.36 
 637.94 
 
 1 
 
 113.883 
 114.275 
 
 1032.1 
 1039.2 
 
 % 
 
 65.188 
 
 338.16 
 
 % 
 
 89.928 
 
 643.55 
 
 
 114.668 
 
 1046.3 
 
 % 
 
 65.581 
 
 342.25 
 
 % 
 
 90.321 
 
 649.18 
 
 % 
 
 115.061 
 
 1053.5 
 
 21. 
 
 65.973 
 
 346.36 
 
 % 
 
 90.713 
 
 654.84 
 
 % 
 
 115.454 
 
 1060.7 
 
 % 
 
 66.366 
 
 350.50 
 
 29. 
 
 91.106 
 
 660.52 
 
 % 
 
 115.846 
 
 1068.0 
 
 V* 
 
 66.759 
 
 354.66 
 
 Vs 
 
 91.499 
 
 666.23 
 
 37. 
 
 116.239 
 
 1075.2 
 
 % 
 
 67.152 
 
 358.84 
 
 % 
 
 91.892 
 
 671.96 
 
 ys 
 
 116.632 
 
 1082.5 
 
 
 67.544 
 
 363.05 
 
 % 
 
 92.284 
 
 677.71 
 
 y* 
 
 117.024 
 
 1089.8 
 
 5^ 
 
 67.937 
 
 367.28 
 
 ya 
 
 92.677 
 
 683.49 
 
 % 
 
 117.417 
 
 1097.1 
 
 % 
 
 68.330 
 
 371.54 
 
 
 93.070 
 
 689.30 
 
 y 2 
 
 117.810 
 
 1104.5 
 
 % 
 
 68.722 
 
 375.83 
 
 
 93.462 
 
 695 13 
 
 % 
 
 118.202 
 
 1111.8 
 
 32. 
 
 69.115 
 
 380.13 
 
 7 /8 
 
 93.855 
 
 700.98 
 
 % 
 
 118.596 
 
 1119.2 
 
 y 8 
 
 69.508 
 
 384.46 
 
 30. 
 
 94.248 
 
 706.86 
 
 7/ 8 118.988 
 
 1126.7 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book" 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 399 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 38. 
 
 119.381 
 
 1134.1 
 
 45% 
 
 144.121 
 
 1652.9 
 
 538/4 
 
 168.861 
 
 2269.1 
 
 ft 
 
 119.773 
 
 1141.6 
 
 46. 
 
 144.513 
 
 1661.9 
 
 % 
 
 169.253 
 
 2279.6 
 
 % 
 
 120.166 
 
 1149.1 
 
 Vs 
 
 144.906 
 
 1670.9 
 
 54. 
 
 169.646 
 
 2290.2 
 
 % 
 
 120.559 
 
 1156.6 
 
 H 
 
 145.299 
 
 1680.0 
 
 % 
 
 170.039 
 
 2300.8 
 
 Va 
 
 120.951 
 
 1164.2 
 
 % 
 
 145.691 
 
 1689.1 
 
 V4 
 
 170.431 
 
 2311.5 
 
 % 
 
 121.344 
 
 1171.7 
 
 Va 
 
 146.084 
 
 1698.2 
 
 % 
 
 170.824 
 
 2322.1 
 
 % 
 
 121.737 
 
 1179.3 
 
 % 
 
 146.477 
 
 1707.4 
 
 Va 
 
 171.217 
 
 2332.8 
 
 % 
 
 122.129 
 
 1186.9 
 
 94 
 
 146.869 
 
 1716.5 
 
 % 
 
 171.609 
 
 2343.5 
 
 39. 
 
 122.522 
 
 1194.6 
 
 7 /8 
 
 147.262 
 
 1725.7 
 
 % 
 
 172.002 
 
 2354.3 
 
 Vs 
 
 122.915 
 
 1202.3 
 
 47. f 
 
 147.655 
 
 1734.9 
 
 % 
 
 172.395 
 
 2365.0 
 
 % 
 
 123.308 
 
 1210.0 
 
 
 148.048 
 
 1744.2 
 
 55. 
 
 172.788 
 
 2375.8 
 
 % 
 
 123.700 
 
 1217.7 
 
 14 
 
 148.440 
 
 1753.5 
 
 Vs 
 
 173.180 
 
 2386.6 
 
 Va 
 
 124.093 
 
 1225.4 
 
 % 
 
 148.833 
 
 1762.7 
 
 % 
 
 173.573 
 
 2397.5 
 
 % 
 
 124.486 
 
 1233.2 
 
 }/ 
 
 149.226 
 
 1772.1 
 
 % 
 
 173.966 
 
 2408.3 
 
 4 
 
 124.878 
 
 1241.0 
 
 
 149.618 
 
 1781.4 
 
 y 2 
 
 174.358 
 
 2419.2 
 
 7 /8 
 
 125.271 
 
 1248.8 
 
 
 150.011 
 
 1790.8 
 
 % 
 
 174.751 
 
 2430.1 
 
 40. 
 
 125.664 
 
 1256.6 
 
 7 /8 
 
 150.404 
 
 1800.1 
 
 % 
 
 175.144 
 
 2441.1 
 
 Vs 
 
 126.056 
 
 1264.5 
 
 48. 
 
 150.796 
 
 1809.6 
 
 7 /8 
 
 175.536 
 
 2452.0 
 
 V4 
 
 126.449 
 
 1272.4 
 
 Vs 
 
 151.189 
 
 1819.0 
 
 56. 
 
 175.929 
 
 2463.0 
 
 % 
 
 126.842 
 
 1280.3 
 
 % 
 
 151.582 
 
 1828.5 
 
 % 
 
 176.322 
 
 2474.0 
 
 Vz 
 
 127.235 
 
 1288.2 
 
 % 
 
 151.975 
 
 1837.9 
 
 J /4 
 
 176.715 
 
 2485.0 
 
 % 
 
 127.627 
 
 1296.2 
 
 Va 
 
 152.367 
 
 1847.5 
 
 % 
 
 177.107 
 
 2496.1 
 
 ' 
 
 128.020 
 
 1304.2 
 
 % 
 
 152.760 
 
 1857.0 
 
 y 2 
 
 177.500 
 
 2507.2 
 
 *V& 
 
 128.413 
 
 1312.2 
 
 % 
 
 153.153 
 
 1866.5 
 
 
 177.893 
 
 2518.3 
 
 41. 
 
 128.805 
 
 1320.3 
 
 7 /8 
 
 153.545 
 
 1876.1 
 
 
 178.285 
 
 2529.4 
 
 % 
 
 129.198 
 
 1328.3 
 
 49. 
 
 153.938 
 
 1885.7 
 
 7 /8 
 
 178.678 
 
 2540.6 
 
 5 
 
 129.591 
 
 1336.4 
 
 Vs 
 
 154.331 
 
 1895.4 
 
 57. 
 
 179.071 
 
 2551.8 
 
 % 
 
 129.983 
 
 1344.5 
 
 Yi 
 
 154.723 
 
 1905.0 
 
 % 
 
 179.463 
 
 2563.0 
 
 > 
 
 130.376 
 
 1352.7 
 
 % 
 
 155.116 
 
 1914.7 
 
 V4 
 
 179.856 
 
 2574.2 
 
 5 /8 
 
 130.769 
 
 1360.8 
 
 Va 
 
 155.509 
 
 1924.4 
 
 % 
 
 180.249 
 
 2585.4 
 
 % 
 
 131.161 
 
 1369.0 
 
 % 
 
 155.902 
 
 1934.2 
 
 Va 
 
 180.642 
 
 2596.7 
 
 7 /8 
 
 131.554 
 
 1377.2 
 
 8 /4 
 
 156.294 
 
 1943.9 
 
 % 
 
 181.034 
 
 2608.0 
 
 43. 
 
 131.947 
 
 1385.4 
 
 7 /8 
 
 156.687 
 
 1953.7 
 
 % 
 
 181.427 
 
 2619.4 
 
 Vs 
 
 132.340 
 
 1393.7 
 
 50. 
 
 157.080 
 
 1963.5 
 
 % 
 
 181.820 
 
 2630.7 
 
 ft 
 
 132.732 
 
 1402.0 
 
 % 
 
 157.472 
 
 1973.3 
 
 58. 
 
 182.212 
 
 2642.1 
 
 % 
 
 133.125 
 
 1410.3 
 
 y* 
 
 157.865 
 
 1983.2 
 
 Vs 
 
 182.605 
 
 2653.5 
 
 Va 
 
 133.518 
 
 1418.6 
 
 % 
 
 158.258 
 
 1993.1 
 
 V4 
 
 182.998 
 
 2664.9 
 
 % 
 
 133.910 
 
 1427.0 
 
 Va 
 
 158.650 
 
 2003.0 
 
 % 
 
 183.390 
 
 2676.4 
 
 % 
 
 134.303 
 
 1435.4 
 
 % 
 
 159.043 
 
 2012.9 
 
 Va 
 
 183.783 
 
 2687.8 
 
 7 /8 
 
 134.696 
 
 1443.8 
 
 % 
 
 159.436 
 
 2022.8 
 
 % 
 
 184.176 
 
 2699.3 
 
 43. 
 
 135.088 
 
 1452.2 
 
 % 
 
 159.829 
 
 2032.8 
 
 % 
 
 184.569 
 
 2710.9 
 
 Vs 
 
 135.481 
 
 1460.7 
 
 51. 
 
 160.221 
 
 2042.8 
 
 7 /8 
 
 184.961 
 
 2722.4 
 
 % 
 
 135.874 
 
 1469.1 
 
 Vs 
 
 160.614 
 
 2052.8 
 
 59. 
 
 185.354 
 
 2734.0 
 
 % 
 
 136.267 
 
 1477.6 
 
 ^4 
 
 161.007 
 
 2062.9 
 
 % 
 
 185.747 
 
 2745.6 
 
 % 
 
 136.659 
 
 1486.2 
 
 8 /8 
 
 161.399 
 
 2073.0 
 
 V4 
 
 186.139 
 
 2757.2 
 
 % 
 
 137.052 
 
 1494.7 
 
 1/2 
 
 161.792 
 
 2083.1 
 
 % 
 
 186.532 
 
 2768.8 
 
 % 
 
 137.445 
 
 1503.3 
 
 
 162.185 
 
 2093.2 
 
 Va 
 
 186.925 
 
 2780.5 
 
 7 /8 
 
 137.837 
 
 1511.9 
 
 
 162.577 
 
 2103.3 
 
 
 187.317 
 
 2792.2 
 
 44. 
 
 138.230 
 
 1520.5 
 
 7 /8 
 
 162.970 
 
 2113.5 
 
 
 187.710 
 
 2803.9 
 
 Vs 
 
 138.623 
 
 1529.2 
 
 52. 
 
 163.363 
 
 2123.7 
 
 
 188.103 
 
 2815.7 
 
 y* 
 
 139.015 
 
 1537.9 
 
 % 
 
 163.756 
 
 2133.9 
 
 60. 
 
 188.496 
 
 2827.4 
 
 % 
 
 139.408 
 
 1546.6 
 
 V4 
 
 164.148 
 
 2144.2 
 
 Vs 
 
 188.888 
 
 2839.2 
 
 % 
 
 139.801 
 
 1555.3 
 
 % 
 
 164.541 
 
 2154.5 
 
 $4 
 
 189.281 
 
 2851.0 
 
 % 
 
 140.194 
 
 1564.0 
 
 ft 
 
 164.934 
 
 2164.8 
 
 % 
 
 189.674 
 
 2862.9 
 
 % 
 
 140.586 
 
 1572.8 
 
 
 165.326 
 
 2175.1 
 
 y 3 
 
 190.066 
 
 2874.8 
 
 7 /8 
 
 140.979 
 
 1581.6 
 
 
 165.719 
 
 2185.4 
 
 % 
 
 190.459 
 
 2886.6 
 
 45. 
 
 141.372 
 
 1590.4 
 
 7 /8 
 
 166.112 
 
 2195.8 
 
 % 
 
 190.852 
 
 2898.6 
 
 % 
 
 141.764 
 
 1599.3 
 
 53. 
 
 166.504 
 
 2206.2 
 
 % 
 
 191.244 
 
 2910.5 
 
 Vt 
 
 142.157 
 
 1608.2 
 
 Vs 
 
 166.897 
 
 2216.6 
 
 61. 
 
 191.637 
 
 2922.5 
 
 % 
 
 142.550 
 
 1617.0 
 
 
 167.290 
 
 2227.0 
 
 Vs 
 
 192.030 
 
 2934.5 
 
 Va 
 
 142.942 
 
 1626.0 
 
 % 
 
 167.683 
 
 2237.5 
 
 V4 
 
 192.423 
 
 2946.5 
 
 % 
 
 143.335 
 
 1634.9 
 
 I/. 
 
 168.075 
 
 2248.0 
 
 % 
 
 192.815 
 
 2958.5 
 
 % 
 
 143.728 
 
 1643.9 
 
 % 
 
 168.468 
 
 2258.5 
 
 Va 
 
 193.208 
 
 2970.6 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
400 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. Area 
 
 61% 
 
 193.601 
 
 2982.7 
 
 69y 2 
 
 218.341 
 
 3793.7 
 
 77% 
 
 243.081 4702.1 
 
 
 193.993 
 
 2994.8 
 
 % 
 
 218.733 
 
 3807.3 
 
 V2 
 
 243.473 4717.3 
 
 % 
 
 194.386 3006.9 
 
 % 
 
 219.126 
 
 3821.0 
 
 
 243.866 4732.5 
 
 62. 
 
 194.779i 3019.1 
 
 % 
 
 219.519 
 
 3834.7 
 
 8 /4 
 
 244.259 4747.8 
 
 
 195.171 
 
 3031.3 
 
 70. 
 
 219.911 
 
 3848.5 
 
 
 244.652 ; 4763.1 
 
 V 
 
 195.564 
 
 3043.5' 
 
 
 220.304 
 
 3862.2 
 
 78? 
 
 245.044 
 
 4778.4 
 
 % 
 
 195.957 
 
 3055.7 
 
 V4 
 
 220.697 
 
 3876.0 
 
 Ys 
 
 245.437 
 
 4793.7 
 
 
 196.350 
 
 3068.0 
 
 % 
 
 221.090 
 
 3889.8 
 
 
 245.830 
 
 4809.0 
 
 
 196.742 
 
 3080.3 
 
 Vz 
 
 221.482 
 
 3903.6 
 
 % 
 
 246.222 
 
 4824.4 
 
 
 197.135 
 
 3092.6 
 
 % 
 
 221.875 
 
 3917.5 
 
 2 
 
 246.615 
 
 4839.8 
 
 7/8 
 
 197.528 
 
 3104.9 
 
 94 
 
 222.268 
 
 3931.4 
 
 
 247.008 
 
 4855.2 
 
 63. 
 
 197.920 
 
 3117.2 
 
 7/8 
 
 222.660 
 
 3945.3 
 
 
 247.400 
 
 4870.7 
 
 Vs 
 
 198.313 
 
 3129.6 
 
 71. 
 
 223.053 
 
 3959.2 
 
 
 247.793 
 
 4886.2 
 
 V4 
 
 198.706 
 
 3142.0 
 
 
 223.446 
 
 3973.1 
 
 79* 
 
 248.186 
 
 4901.7 
 
 
 199.098 
 
 3154.5 
 
 -V4 
 
 223.838 
 
 3987.1 
 
 Vs 
 
 248.579 
 
 4917.2 
 
 V2 
 
 199.491 
 
 3166.9 
 
 % 
 
 224.231 
 
 4001.1 
 
 
 248.971 
 
 4932.7 
 
 
 199.884 
 
 3179.4 
 
 Va 
 
 224.624 
 
 4015.2 
 
 % 
 
 249.364 
 
 4948.3 
 
 % 
 
 200.277 
 
 3191.9 
 
 
 225.017 
 
 4029.2 
 
 % 
 
 249.757 
 
 4963.9 
 
 7/8 
 
 200.669 
 
 3204.4 
 
 % 
 
 225.409 
 
 4043.3 
 
 % 
 
 250.149 
 
 4979.5 
 
 64. 
 
 201.062 
 
 3217.0 
 
 7/8 
 
 225.802 
 
 4057.4 
 
 % 
 
 250.542 
 
 4995.2 
 
 
 201.455 
 
 3229.6 
 
 73. 
 
 226.195 
 
 4071.5 
 
 % 
 
 250.935 
 
 5010.9 
 
 5 
 
 201.847 
 
 3242.2 
 
 H 
 
 226.587 
 
 4085.7 
 
 80. 
 
 251.327 
 
 5026.5 
 
 
 202.240 
 
 3254.8 
 
 
 226.980 
 
 4099.8 
 
 
 251.720 
 
 5042.3 
 
 % 
 
 202.633 
 
 3267.5 
 
 % 
 
 227.373 
 
 4114.0 
 
 ^4 
 
 252.113 
 
 5058.0 
 
 
 203.025 
 
 3280.1 
 
 
 227.765 
 
 4128.2 
 
 % 
 
 252.506 
 
 5073.8 
 
 % 
 
 203.418 
 
 3292.8 
 
 
 228.158 
 
 4142.5 
 
 2 
 
 252.898 
 
 5089.6 
 
 7 & 
 
 203.811 
 
 3305.6 
 
 
 228.551 
 
 4156.8 
 
 
 253.291 
 
 5105.4 
 
 65. 
 
 204.204 
 
 3318.3 
 
 7 /8 
 
 228.944 
 
 4171.1 
 
 % 
 
 253.684 
 
 5121.2 
 
 
 204.596 
 
 3331.1 
 
 73. 
 
 229.336 
 
 4185.4 
 
 7/8 
 
 254.076 
 
 5137.1 
 
 V4 
 
 204.989 
 
 3343.9 
 
 
 229.729 
 
 4199.7 
 
 81. 
 
 254.469 
 
 5153.0 
 
 % 
 
 205.382 
 
 3356.7 
 
 y. 
 
 230.122 
 
 4214.1 
 
 H 
 
 254.862 
 
 5168.9 
 
 % 
 
 205.774 
 
 3369.6 
 
 % 
 
 230.514 
 
 4228.5 
 
 
 255.254 
 
 5184.9 
 
 
 206.167; 3382.4 
 
 2 
 
 230.907 
 
 4242.9 
 
 % 
 
 255.647 
 
 5200.8 
 
 
 206.560 3395.3 
 
 % 
 
 231.300 
 
 4257.4 
 
 V2 
 
 256.040 
 
 5216.8 
 
 
 206.952 
 
 3408.2 
 
 
 231.692 
 
 4271.8 
 
 
 256.433 
 
 5232.8 
 
 66. 
 
 207.345 
 
 3421.2 
 
 % 
 
 232.085 
 
 4286.3 
 
 S A 
 
 256.825 
 
 5248.9 
 
 
 207.738 
 
 3434.2 
 
 74. 
 
 232.478 
 
 4300.8 
 
 % 
 
 257.218 
 
 5264.9 
 
 % 
 
 208.131 
 
 3447.2 
 
 Ys 
 
 232.871 
 
 4315.4 
 
 82^ 
 
 257.611 
 
 5281.0 
 
 
 208.523 3460.2 
 
 1/4 
 
 233.263 
 
 4329.9 
 
 
 258.003 
 
 5297.1 
 
 |L 
 
 208.916, 3473.2 
 
 
 233.656 
 
 4344.5 
 
 
 258.396 
 
 5313.3 
 
 % 
 
 209.309 3486.3 
 
 Yz 
 
 234.049 
 
 4359.2 
 
 
 258.789 
 
 5329.4 
 
 % 
 
 209.701 3499.4 
 
 % 
 
 234.441 
 
 4373.8 
 
 % 
 
 259.181 
 
 5345.6 
 
 7/8 
 
 210.094 3512.5 
 
 % 
 
 234.834 
 
 4388.5 
 
 
 259.574 
 
 5361.8 
 
 67. 
 
 210.487 3525.7 
 
 7/8 
 
 235.227 
 
 4403.1 
 
 % 
 
 259.967 
 
 5378.1 
 
 Vs 
 
 210.879 3538.8 
 
 75. 
 
 235.619 
 
 4417.9 
 
 7/8 
 
 260.359 
 
 5394.3 
 
 
 211.272 3552.0 
 
 % 
 
 236.012 
 
 4432.6 
 
 83. 
 
 260.752 
 
 5410.6 
 
 % 
 
 211.665 3565.2 
 
 y* 
 
 236.405 
 
 4447.4 
 
 % 
 
 261 . 145 
 
 5426.9 
 
 
 212.058 
 
 3578.5 
 
 
 236.798 
 
 4462.2 
 
 
 261.538 
 
 5443.3 
 
 % 
 
 212.450 
 
 3591.7 
 
 2 
 
 237.190 
 
 4477.0 
 
 % 
 
 261.930 
 
 5459.6 
 
 % 
 
 212.843 
 
 3605.0 
 
 
 237.583 
 
 4491.8 
 
 Yz 
 
 262.323 
 
 5476.0 
 
 7/8 
 
 213.236 3618.3 
 
 
 237.976 
 
 4506.7 
 
 
 262.716 
 
 5492.4 
 
 68. 
 
 213.628J 3631.7 
 
 . 
 
 238.368 
 
 4521.5 
 
 
 263.108 
 
 5508.8 
 
 
 214.021 3645.0 
 
 76. 
 
 238.761 
 
 4536.5 
 
 7/8 
 
 263.501 
 
 5525.3 
 
 V4 
 
 214.414 3658.4 
 
 ft 
 
 239.154 
 
 4551.4 
 
 84. 
 
 263.894 
 
 5541.8 
 
 
 214.806 3671.8 
 
 V4 
 
 239.546 
 
 4566.4 
 
 ft 
 
 264.286 
 
 5558.3 
 
 % 
 
 215.199 3685.3 
 
 
 239.939 
 
 4581.3 
 
 % 
 
 264.679 
 
 5574.8 
 
 % 
 
 215.592 3698.7 
 
 14 
 
 240.332 
 
 4596.3 
 
 
 265.072 
 
 5591.4 
 
 
 215.984 3712.2 
 
 B 8 
 
 240.725 
 
 4611.4 
 
 1/L 
 
 265.465 
 
 5607.9 
 
 % 
 
 216.377 3725.7 
 
 % 
 
 241.117 
 
 4626.4 
 
 
 265.857 
 
 5624.5 
 
 69. 
 
 216.770 3739.3 
 
 % 
 
 241.510 
 
 4641.5 
 
 
 266.250 
 
 5641.2 
 
 
 217.163 3752.8 
 
 77. 
 
 241.903 
 
 4656.6 
 
 1' 
 
 266.643 
 
 5657.8 
 
 i/. 
 
 217.555 3766.4 
 
 
 242.295 
 
 4671.8 
 
 85. /8 
 
 267.035 
 
 5674.5 
 
 % 
 
 217.948J 3780.0 
 
 ft 
 
 242.688 
 
 4686.9 
 
 Vs 
 
 267.428 
 
 5691.2 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
ELECTRIC INTERLOCKING HANDBOOK 
 
 401 
 
 Dlam. 
 
 Circum. 
 
 Area 
 
 Dlam. 
 
 Circum. 
 
 Area 
 
 Diam. 
 
 Circum. 
 
 Area 
 
 85*4 
 
 267.821 
 
 5707.9 
 
 90^4 
 
 283.529 
 
 6397.1 
 
 95V4 
 
 299.237 
 
 7125.6 
 
 % 
 
 268.213 
 
 5724.7 
 
 % 
 
 283.921 
 
 6414.9 
 
 % 
 
 299.629 
 
 7144.3 
 
 s 
 
 268.606 
 
 5741.5 
 
 
 284.314 
 
 6432.6 
 
 y 2 
 
 300.022 
 
 7163.0 
 
 % 
 
 268.999 
 
 5758.3 
 
 
 284.707 
 
 6450.4 
 
 % 
 
 300.415 
 
 7181.8 
 
 % 
 
 269.392 
 
 5775.1 
 
 
 285.100 
 
 6468.2 
 
 % 
 
 300.807 
 
 7200.6 
 
 7 /8 
 
 269.784 
 
 5791.9 
 
 % 
 
 285.492 
 
 6486.0 
 
 .% 
 
 301.200 
 
 7219.4 
 
 86. 
 
 270.177 
 
 5808.8 
 
 91. 
 
 285.885 
 
 6503.9 
 
 96. 
 
 301.593 
 
 7238.2 
 
 Vs 
 
 270.570 
 
 5825.7 
 
 
 286.278 
 
 6521.8 
 
 46 
 
 301.986 
 
 7257.1 
 
 % 
 
 270.962 
 
 5842.6 
 
 % 
 
 286.670 
 
 6539.7 
 
 % 
 
 302.378 
 
 7276.0 
 
 % 
 
 271.355 
 
 5859.6 
 
 % 
 
 287.063 
 
 6557.6 
 
 % 
 
 302.771 
 
 7294.9 
 
 % 
 
 271.748 
 
 5876.5 
 
 Vs 
 
 287.456 
 
 6575.5 
 
 2 
 
 303.164 
 
 7313.8 
 
 
 272.140 
 
 5893.5 
 
 % 
 
 287.848 
 
 6593.5 
 
 % 
 
 303.556 
 
 7332.8 
 
 94 
 
 272.533 
 
 5910.6 
 
 % 
 
 288.241 
 
 6611.5 
 
 % 
 
 303.949 
 
 7351.8 
 
 % 
 
 272.926 
 
 5927.6 
 
 % 
 
 288.634 
 
 6629.6 
 
 7 /8 
 
 304.342 
 
 7370.8 
 
 87. 
 
 273.319 
 
 5944.7 
 
 93. 
 
 289.027 
 
 6647.6 
 
 97. 
 
 304.734 
 
 7389.8 
 
 
 273.711 
 
 5961.8 
 
 Vs 
 
 289.419 
 
 6665.7 
 
 % 
 
 305.127 
 
 7408.9 
 
 i/ 
 
 274.104 
 
 5978.9 
 
 % 
 
 289.812 
 
 6683.8 
 
 % 
 
 305.520 
 
 7428.0 
 
 % 
 
 274.497 
 
 5996.0 
 
 % 
 
 290.205 
 
 6701.9 
 
 % 
 
 305.913 
 
 7447.1 
 
 Vfc 
 
 274.889 
 
 6013.2 
 
 5 
 
 290.597 
 
 6720.1 
 
 V2 
 
 306.305 
 
 7466.2 
 
 
 275.282 
 
 6030.4 
 
 % 
 
 290.990 
 
 6738.2 
 
 % 
 
 306.698 
 
 7485.3 
 
 
 275.675 
 
 6047.6 
 
 % 
 
 291.383 
 
 6756.4 
 
 tft 
 
 307.091 
 
 7504.5 
 
 7 /8 
 
 276.067 
 
 6064.9 
 
 % 
 
 291.775 
 
 6774.7 
 
 % 
 
 307.483 
 
 7523.7 
 
 88. 
 
 276.460 
 
 6082.1 
 
 93. 
 
 292.168 
 
 6792.9 
 
 98. 
 
 307.876 
 
 7543.0 
 
 Vs 
 
 276.853 
 
 6099.4 
 
 
 292.561 
 
 6811.2 
 
 
 308.269 
 
 7562.2 
 
 ^4 
 
 277.246 
 
 6116.7 
 
 I/, 
 
 292.954 
 
 6829.5 
 
 i^ 
 
 308.661 
 
 7581.5 
 
 % 
 
 277.638 
 
 6134.1 
 
 % 
 
 293.346 
 
 6847.8 
 
 % 
 
 309.054 
 
 7600.8 
 
 Va 
 
 278.031 
 
 6151.4 
 
 % 
 
 293.739 
 
 6866.1 
 
 Vis 
 
 309.447 
 
 7620.1 
 
 
 278.424 
 
 6168.8 
 
 % 
 
 294.132 
 
 6884.5 
 
 % 
 
 309.840 
 
 7639.5 
 
 
 278.816 
 
 6186.2 
 
 % 
 
 294.524 
 
 6902.9 
 
 % 
 
 310.232 
 
 7658.9 
 
 7 /8 
 
 279.209 
 
 6203.7 
 
 % 
 
 294.917 
 
 6921.3 
 
 % 
 
 310.625 
 
 7678.3 
 
 89. 
 
 279.602 
 
 6221.1 
 
 94. 
 
 295.310 
 
 6939.8 
 
 99. 
 
 311.018 
 
 7697.7 
 
 Vs 
 
 279.994 
 
 6238.6 
 
 44 
 
 295.702 
 
 6958.2 
 
 % 
 
 311.410 
 
 7717.1 
 
 % 
 
 280.387 
 
 6256.1 
 
 % 
 
 296.095 
 
 6976.7 
 
 V4 
 
 311.803 
 
 7736.6 
 
 % 
 
 280.780 
 
 6273.7 
 
 $ 
 
 296.488 
 
 6995.3 
 
 
 312.196 
 
 7756.1 
 
 
 281.173 
 
 6291.2 
 
 2 
 
 296.881 
 
 7013.8 
 
 
 312.588 
 
 7775.6 
 
 % 
 
 281.565 
 
 6308.8 
 
 % 
 
 297.273 
 
 7032.4 
 
 
 312.981 
 
 7795.2 
 
 % 
 
 281.958 
 
 6326.4 
 
 % 
 
 297.666 
 
 7051.0 
 
 % 
 
 313.374 
 
 7814.8 
 
 % 
 
 282.351 
 
 6344.1 
 
 % 
 
 298.059 
 
 7069.6 
 
 % 
 
 313.767 
 
 7834.4 
 
 90. 
 
 282.743 
 
 6361.7 
 
 95. 
 
 298.451 
 
 7088.2 
 
 100. 
 
 314.159 
 
 7854.0 
 
 Vs 
 
 283.136 
 
 6379.4 
 
 % 
 
 298.844 
 
 7106.9 
 
 
 
 
 Reprinted by permission from "Kent's Mechanical Engineers' Pocket Book." 
 
SECTION XVIII 
 
 APPENDIX 
 
 COVERING REPRINT OF PREFACE 
 FROM TAYLOR (G. R. S.) CATALOGUE 
 NO. 1, INFORMATION REQUIRED FOR 
 THE DRAWING UP OF INTERLOCKING 
 ESTIMATES, AND A LIST OF G. R. S. 
 ELECTRIC INTERLOCKING LEVERS 
 INSTALLED 
 
APPENDIX 
 
 REPRINT OF PREFACE 
 
 From Catalogue No. 1 (1902), Taylor Signal Company, Buffalo, 
 N. Y. Taylor Signal Company acquired by the General Rail- 
 way Signal Company in 1904. 
 
 IN the last few years there has been a phenomenal increase 
 in tonnage hauled on American railways, necessitating 
 the purchase of more and better engines and cars of larger 
 capacity, equipped with the best safety devices. Enor- 
 mous sums have been expended in taking out curves, cutting 
 down grades, laying additional main tracks, putting in new 
 sidings, and providing improved terminal facilities. But, 
 notwithstanding all these improvements, many lines find it 
 impossible to handle their business with sufficient dispatch to 
 avoid congestion. This fact has led many progressive Ameri- 
 can railway managers to realize that if they are to secure the 
 best and most economical returns from the great expenditures 
 made for motive power, car equipment, and tracks, suitable 
 means must be provided to enable their trains to move with a 
 minimum of delays and a maximum of safety; and this can 
 only be realized when train orders are supplanted by an up-to- 
 date block system and hand operated switches by a modern 
 system of interlocking. 
 
 The very highest development of the art of signaling has 
 been reached in this country, but no American railway is nearly 
 so thoroughly equipped with signaling as is the average English 
 line. 
 
 This lack of signal equipment will be better comprehended 
 after considering some simple statistics. 
 
 The first interlocking plant installed on the London and 
 Northwestern Railway was put in service in 1859; fourteen 
 years later, in 1873, there were in use on that line alone 13,000 
 levers. At the same date there was not a single interlocking 
 plant in use in the United States, the first plant in this country 
 having been installed in the year 1874 by Messrs. Toucy and 
 Buchanan at Spuyten Duyvil Junction, in New York City. 
 
 At the present time (1902) there are in use on the 1,800 
 miles of line of the London and Northwestern Railway ap- 
 proximately 36,000 interlocked levers, or an average of about 
 twenty levers per mile of line, whereas there are only about 
 40,000 in use on all lines of the United States, or, approxi- 
 mately, one lever to five miles of line, or about 1 'per cent, 
 of the number of levers per mile used on the London and 
 Northwestern Railway. 
 
 When it is remembered that probably more than one-half 
 of the interlocked levers in use in this country are at grade 
 crossings, leaving fewer than 20,000 levers used for station, 
 yard and terminal work, whereas practically the entire 36,000 
 
406 GENERAL RAILWAY SIGNAL COMPANY 
 
 on the L. & N. W. are used for such work alone, it will be recog- 
 nized that American railways are in general very poorly pro- 
 vided with modern signal appliances. In fact, there is probably 
 to-day not a single American railway that is nearly so thor- 
 oughly equipped as the London and Northwestern was twenty- 
 seven years ago, though, as might be expected, the devices in 
 use on American lines haying properly organized signal depart- 
 ments, capable of making suitable specifications, compare 
 favorably with the best in use on European lines and, in nu- 
 merous instances, large power plants are in use which are supe- 
 rior to anything ever devised abroad. 
 
 There can be no question as to the inability of most of our 
 railways to move their trains with proper safety and dispatch 
 during times when traffic is heavy; no competent railway 
 operating officer doubts that proper systems of signaling would 
 greatly aid in the safer and more rapid movement of trains 
 and, while there are probably few American railway men 
 who recognize fully how very far behind the best European 
 lines our lines are in respect to the completeness of their signal 
 equipment, this is becoming better understood every year 
 and there is reason to believe that our most progressive lines 
 will not much longer continue to limit the applications of 
 interlocking to the protection of grade crossings with here 
 and there a junction or yard plant. 
 
 Such being the case, it is probable that more signaling will 
 be done in the near future than has ever before been done in 
 this country and American railway managers will, therefore, 
 find it greatly to their advantage to give serious consideration 
 to the determination of what system of interlocking they can 
 best use. 
 
 The earliest system employed and that in most general use 
 at this time is the so-called "mechanical interlocking" in 
 which the switches or signals are manually worked by means 
 of interlocked levers connected with them by pipe or wire lines. 
 
 When properly installed, this system has given satisfactory 
 results; but, unfortunately, in the effort of railway men to 
 secure cheap appliances and in the stress of competition be- 
 tween the various manufacturers of signaling devices, a great 
 many of the installations made in this country are very imper- 
 fect and unsafe. 
 
 Experience has shown that, in order to secure a reasonable 
 degree of safety, it is absolutely essential that the following 
 requirements be met : 
 
 All derails, movable point frogs, locks, switches and home 
 signals should be worked by pipe ; no signal should be worked 
 by a single wire ; all pipe and wire lines should be automatic- 
 ally compensated ; all derails, movable point frogs and facing 
 point switches should be provided with duplex facing point 
 locks; all cranks and pipe compensators should be fixed on 
 strong foundations set in best quality concrete; no facing 
 point switch more than 600 feet from the tower should be 
 
ELECTRIC INTERLOCKING HANDBOOK 407 
 
 taken into the system ; no lever should "be overloaded by 
 putting on it such a number of switches and bars as to pre- 
 vent a man of average strength from throwing it with one 
 hand. 
 
 Where these and other proper specifications have been fol- 
 lowed, fair results have been obtained, though it has long 
 been recognized by American railway operating officials that 
 this system has inherent defects that render it, under certain 
 conditions, unsafe. For example, in the event of the breakage 
 of a pipe or wire operating a signal, there can be no absolute 
 assurance that such breakage will be known by the leverman 
 or that such signal will occupy a position corresponding with 
 that of its lever or that it will not indicate "line clear" when, 
 its lever being normal, another and opposing signal is set at 
 "line clear." 
 
 The fatigue incident to working mechanical levers is very 
 great, so that it is frequently necessary to employ three eight- 
 hour levermen for a comparatively small plant where the 
 number of lever movements is considerable; if the plant is 
 very large, it is sometimes necessary to employ as many as 
 eight men on each of three shifts. 
 
 Moreover, under certain conditions it is very costly to operate 
 such a system. For example, in cases where the distance 
 between the extreme switches to be operated is over 1,600 
 feet, it is generally necessary to provide two mechanical inter- 
 locking towers, each with its own set of levermen, as it is 
 neither safe nor practicable to work such switches from one 
 tower. It is interesting to note in this connection that under 
 the English Board of Trade requirements, which are wisely 
 drawn and rigidly enforced, no facing point switch may be 
 operated at a distance exceeding 540 feet from the tower. 
 Even at this distance it is considered that ordinary pipe lines 
 are not sufficiently strong or safe and many English lines now 
 employ a steel channel section, cut to eighteen foot lengths and 
 jointed by means of fish plates secured by six one-half inch 
 bolts, this construction admitting of ready detection of rods 
 weakened by corrosion and of their easy removal.- 
 
 In order to overcome these and other disadvantages inherent 
 in systems of mechanical interlocking, the "pneumatic system " 
 was devised by Mr. George Westinghouse, Jr., the first working 
 installation having been made at the crossing of the P. and R. 
 and L. V. Railways, near Bound Brook, N. J., in 1884. 
 
 At the present time two varieties of this system are in use, 
 one, popularly known as the "electro-pneumatic," in which 
 air compressed to a working pressure of about sixty pounds 
 is employed for moving switches and signals and in which the 
 release locking is effected by electro-magnetic means ; and the 
 other, popularly known as the "low pressure pneumatic," in 
 which air at a pressure of about twenty pounds is used for 
 operation and in which compressed air effects the release 
 locking. 
 
408 GENERAL RAILWAY SIGNAL COMPANY 
 
 Some of the advantages claimed for this system are as 
 follows : 
 
 The ability to operate switches and signals at any desired 
 distance from the cabin ; that switches are actually required 
 to be moved and securely locked in the proper position before 
 a signal governing traffic over them can be cleared ; that each 
 signal, when cleared, automatically locks the lever operating it 
 in such manner as to prevent the release of levers controlling 
 conflicting signals and switches, until such signal has been 
 again placed completely at danger, thus effectually providing 
 against the simultaneous display of two conflicting clear 
 signals; that, there being no moving parts between cabin 
 and switches and signals, wear of mechanism, lost motion and 
 the troublesome and dangerous effects of expansion and con- 
 traction of mechanically operated pipes and wires are all 
 eliminated; that much less room is required for leadout con- 
 nections than in a mechanical plant and much valuable space 
 is thereby saved; that cabins of much smaller and lighter 
 design are used ; that the operation of the machine requires so 
 little physical exertion that one man can do the work that 
 would in a mechanical plant require three or four. 
 
 There can be no doubt that both varieties of the pneumatic 
 system are far better adapted for the working of large plants 
 than the mechanical as both largely fulfill the claims above 
 referred to. 
 
 It is, however, found that in the electro-pneumatic system 
 a cross between the release locking (commonly known as "indi- 
 cation") wire and the common return wire (or ground), will 
 have the same effect as would the closing of the indication cir- 
 cuit in the proper manner, thus giving a false indication, which 
 in view of the fact that the safety of any power interlocking 
 depends upon the reliability of its indications, is highly objec- 
 tionable. It is also found that where the indication is given 
 by means of compressed air the release locking is often effected 
 very slowly in cases where switches or signals are located at a 
 considerable distance from the tower and this, at a busy plant, 
 is also very objectionable. 
 
 Another disadvantage of the low pressure pneumatic system 
 is that if a switch, meeting any obstruction, fails to complete 
 its movement and to give indication, it is necessary either for 
 a repairman to go immediately to the switch and operate it 
 by hand or for the leverman to force the indication, which is 
 often done and is evidently dangerous. Thus, in one style of 
 the pneumatic system there is the defect due to possibility of 
 false indication and in the other the defect due to slow indi- 
 cation and to inability to reverse a switch which has not fully 
 completed its movement. Some other disadvantages of the 
 pneumatic systems are as follows : 
 
 Liability to freezing of pipes and valves in extreme cold 
 weather; high cost of furnishing power; danger of throwing 
 near switches under trains when, owing to extreme cold 
 
ELECTRIC INTERLOCKING HANDBOOK 409 
 
 weather, it is necessary to maintain higher than normal pres- 
 sures in order to be able to work switches farthest from tower ; 
 high cost of maintenance owing to rapid deterioration of iron 
 pipe lines placed underground and subjected to action of 
 various salts and alkalies found in soil and to electrolytic 
 action from electric railway and lighting circuits; difficulty 
 and cost of locating leaks and breaks in pipe lines under ground ; 
 extremely high cost of installing and operating medium sized 
 and small plants or a small number of switches or signals 
 located at a considerable distance from the tower in a large 
 plant. 
 
 To overcome these and other objectionable features of the 
 pneumatic system, the "electric" system was devised. 
 
 This system, the invention of Mr. John D. Taylor of Chilli- 
 cothe, Ohio, was first installed by him on the B. & O. S. W. 
 R'y at East Norwood, near Cincinnati, Ohio, in 1891 ; in 
 1893 certain improvements were introduced by him in the 
 methods of giving indications, the installation remaining 
 otherwise as originally made. For some years afte~ 1893, 
 only a few small installations were made by Mr. Taylo" owing 
 to lack of sufficient capital to develop his inventions on a 
 large scale, but in May, 1900, the Taylor Signal Company was 
 organized in Buffalo, N. Y., and since that time a great number 
 of installations, varying in size from the equivalent of 6 to 225 
 mechanical levers, have been made on important lines of 
 railway in the United States and Europe. 
 
 In the Taylor (G. R. S.) electric system, switches and signals 
 are operated by means of electric motors, the current for 
 these motors being furnished generally by a storage battery, 
 charged from a dynamo driven by an electric motor or gas 
 engine. The release locking is effected by an electro-magnetic 
 device placed under each interlocking lever and actuated by 
 a dynamic current furnished by the switch or signal motor 
 controlled by such lever, when and only when a switch has 
 moved to a position corresponding with that of the lever and is 
 bolt locked in that position or when a signal arm has moved to its 
 full danger position. Crosses between an indication wire and 
 common return wire (or ground) or any other wire of the 
 system, can at worst only prevent the giving of indication and 
 cannot by any possibility result in the giving of a false clear 
 indication as can occur in other systems employing electro- 
 magnetic indications. Moreover, in this system, indications 
 are given instantaneously upon completion of locking of switch 
 or of movement of signal to its stop position, irrespective of 
 the distance of such switch or signal from the tower, thus 
 effecting a great saving in the time required by any system 
 using pneumatic indications, to set up a route. 
 
 If, when a switch is thrown, it fails to complete its move- 
 ment owing to some obstruction between point and stock 
 rail, or for any cause whatever, the switch can be restored by 
 the leverman to its original position and another effort can 
 
410 
 
 GENERAL RAILWAY SIGNAL COMPANY 
 
 be made to perform the desired movement, ofttimes thus 
 avoiding the necessity, so frequently met with in the low 
 pressure pneumatic system, of sending a man out to throw 
 the switch by hand or of forcing the indication. 
 
 The electric is the only power system that can be satisfac- 
 torily employed for the operation of plants having a small 
 number of switches and signals. It is in service where as few 
 as six working levers are employed and is perfectly adapted 
 for use at all junctions, crossings, drawbridges, tunnels, sta- 
 tions, yards, passing sidings, etc., where the distance between 
 extreme switches or signals is greater than can be safely 
 covered with a mechanical plant, even though there be only a 
 very few signals and switches to be operated. For example, 
 consider the two following diagrams, the first one showing 
 arrangement of passing sidings on a single track and the other 
 on a double track line : 
 
 1000167000 
 
 1000 to 7000 
 
 STATION-A 
 
 1000 To 7000' 
 
 1000 to 7000 
 tL, 
 
 ' iJ 6 d 
 
 (GRS-1913) 
 
 STATION* 
 
 On a few of the best signaled American railways the switches 
 and signals immediately adjacent to the station A or B, would 
 be worked by a mechanical interlocking plant, but owing to 
 the great cost of operating an additional mechanical interlock- 
 ing plant at each of the extreme switches and the prohibitive 
 cost of putting in a pneumatic power system by which all the 
 switches and signals could be worked from the station, the 
 inlet switches are left to be worked by the trainmen, necessi- 
 tating the stopping of their trains; and if, as sometimes 
 happens, such stoppage occurs on a bad grade, heavy trains 
 may break in two in starting up. Every practical railway 
 man will at once recognize the tremendous advantage that 
 would be gained if these extreme switches, together with their 
 proper signals, could be safely and economically worked from 
 
ELECTRIC INTERLOCKING HANDBOOK 411 
 
 the station, thereby enabling trains to pass onto and out of 
 passing sidings at speed and in absolute safety. With the 
 Taylor (G. R. S.) electric system this can be effected at a rela- 
 tively small cost, and, in conjunction with a system of auto- 
 matic, electric, track circuit block signals in use on the open 
 road, where there are no switches, this forms the ideal lock 
 and block system and one, which we believe is destined to 
 replace all others both in this country and in Europe. 
 
 In the electric system, the cost of producing power for the 
 operation of switches and signals rarely or never exceeds 
 1 per cent, of the cost in any other power system doing an 
 equal amount of work. For example, if in a system using 
 compressed air, the cost of coal and services of men employed 
 in running power plant is 400 dollars per month, the total cost 
 of producing power for an electric plant doing precisely the 
 same work will rarely or never exceed four dollars monthly. 
 
 In this connection it will be interesting to note that at the 
 South Englewood Taylor (G. R. S.) interlocking plant on the 
 C. R. I. & P. R. R., where the average daily number of switches 
 moved and signals cleared is 2,250, the consumption of gaso- 
 line for running engine for charging storage batteries, was 
 sixty-eight gallons in eighty-six days, or one gallon for 2,845 
 switch and signal operations. At Sixteenth and Clark streets, 
 Chicago, Taylor (G. R. S.) interlocking plant at the crossing 
 of the St. Charles Air Line with the C. R. I. & P. and L. S. & 
 M. S. R'ys, where the movement exceeds 600 trains daily, the 
 consumption of gasoline during 153 days was 222 gallons for 
 642,600 switch and signal movements or 2,894 per gallon or 
 about 326 movements for one cent for power. 
 
 The cost of maintenance and renewals in an electric plant 
 is only a small percentage of the cost in any other power plant. 
 This can be readily understood from the fact that more feet of 
 electrical conductors are employed in the electro-pneumatic 
 system than are used in the Taylor (G. R. S.) system and there 
 are all the pneumatic pipes; and, in the low pressure pneu- 
 matic system, more feet of iron pipe are used than feet of elec- 
 tric conductors in the Taylor (G. R. S.) system, and any one 
 having experience with the rapid deterioration of iron pipes 
 placed in the soils found about railways and subject to elec- 
 trolysis, will have no difficulty in understanding how much 
 shorter lived these underground pipes will be than well insulated 
 copper wires placed in a suitable conduit above ground. Nor 
 is it hard to understand how much more difficult and costly it 
 will be to make repairs to such pipe placed several feet under^ 
 ground than it will be to repair a break or leak in a wire placed 
 in a suitable conduit above ground. 
 
 In this connection, it is interesting to note that the B. & O. 
 S. W. R. R., which was the first to install the Taylor (G. R. S.) 
 system, has found it far cheaper to maintain than an ordinary 
 
 mechanical plant, and this is particularly true where, through 
 change in grade or alignment of tracks, 
 
 any changes are 
 
412 GENERAL RAILWAY SIGNAL COMPANY 
 
 required in the interlocking plant, such changes being many 
 times more costly in any other system than in the Taylor 
 (G. R. S.) electric. Moreover, with the improved devices and 
 methods of installation now used in this system, a far better 
 showing will be made. 
 
 The operation of the electric system is absolutely unaffected 
 by change in temperature, whereas pneumatic systems some- 
 times experience serious difficulties owing to condensation 
 and freezing of moisture contained in the compressed air, by 
 which the mechanism becomes clogged and its working pre- 
 vented. 
 
 Even where the working is not absolutely prevented under 
 these conditions, it frequently becomes necessary to raise the 
 pressure so high in order to compensate for losses in pressure 
 at distant switches, that there is danger of throwing near 
 switches under train, in case leverman makes an improper 
 movement at such a time, as it is certain that as generally 
 installed, detector bar connections are not sufficiently strong 
 to resist any considerable increase above the normal working 
 pressure in a pneumatic plant. It is therefore doubtful 
 whether, during extreme cold weather, it is ever safe to attempt 
 to work from one pneumatic machine, switches and signal, 
 located so far from the tower as to require any increase over 
 normal working pressure. Unquestionably, the safer practice, 
 at such times, is to temporarily abandon the working of such 
 switches and signals, as is often done, though this, of course, 
 causes much troublesome delay and expense. 
 
 In the electric system no such condition exists, as the 
 "electric pressure" is exactly the same on the switch or signal 
 motor located at a distance of 5,000 feet as on one located 
 500 feet from the tower; moreover, the system is so arranged 
 that the throwing of a switch lever while train is over the 
 switch would cause the blowing of a fuse on the machine, 
 thereby opening the circuit. 
 
 In the foregoing statement no effort has been made to de- 
 scribe in detail the appliances and circuits employed in the 
 Taylor (G. R. S.) electric system of interlocking; pur object 
 has been solely to point out the need of signal equipment on 
 American railways and to state, without prejudice, the prin- 
 cipal merits and defects of the several interlocking systems at 
 present employed, in order to aid such railway officials as have 
 not had opportunity to acquaint themselves with the facts 
 above set forth to make an intelligent comparison between 
 such systems. 
 
 The Taylor (G. R. S.) electric system is in the fullest accord 
 with modern engineering practice which has shown, after years 
 of experiment, that transmission of power to a distance can 
 be more satisfactorily accomplithed by means of electricity 
 than by any other agency and, while there is no reason to 
 doubt that this system will be improved in the future as in 
 the past, we feel warranted in claiming at the present time 
 
ELECTRIC INTERLOCKING HANDBOOK 413 
 
 that it represents the very highest development of the art of 
 signaling, embodying features of safety, economy and general 
 applicability not possessed by any other system in use in this 
 country or abroad. 
 
 TAYLOR SIGNAL COMPANY. 
 (GENERAL RAILWAY SIGNAL COMPANY.) 
 
 INFORMATION TO BE FURNISHED BY THE 
 
 RAILWAY COMPANY WHEN REQUESTING AN 
 
 ESTIMATE ON ELECTRIC INTERLOCKING 
 
 In order to prepare promptly an accurate estimate on a pro- 
 posed installation of electric interlocking, it is necessary that 
 definite information on certain items be furnished by the Rail- 
 way Company with the request for a proposal. This informa- 
 tion can best be covered by a specification together with 
 certain plans. 
 
 It is not necessary for each individual railroad to prepare a 
 specification form as the Railway Signal Association adopted, 
 in 1910, a very complete specification covering this practice. 
 The specification has been prepared by a committee of men, 
 actively engaged in railway signal work, and its use is heartily 
 recommended. It can be secured by reference to the Manual 
 of the Railway Signal Association issued in 1912. It has, of 
 course, been necessary in drawing up this specification to 
 leave optional a number of items, definite information on 
 which should be given with each request for an estimate. 
 Attention is especially directed to certain points essential 
 to the preparation of estimates, covered by sections of the 
 specification as follows : 
 
 3. "Drawings." 
 
 A track plan should be furnished giving very completely the 
 information under sub-paragraph 1. The symbols which have 
 been adopted by the Railway Signal Association as shown on 
 pages 348 to 359 of this Handbook should be used. The infor- 
 mation called for in sub-paragraphs 2, 3 and 4 should be given 
 if possible, although this is not absolutely necessary. 
 
 7. "Materials to be furnished and work to be done by and at 
 
 the expense of the Purchaser." 
 
 Consideration should be given to the items listed in this 
 paragraph and note made of any deviation therefrom. 
 
 18. "Transportation." 
 
 A definite statement should be made as to whether trans- 
 portation is to be furnished for men, tools and materials or for 
 either. 
 
414 GENERAL RAILWAY SIGNAL COMPANY 
 
 50. "Building foundations." 
 
 51. "Interlocking station." 
 
 52. "Powerhouse." 
 
 It should be clearly stated whether the contractor is to 
 erect the buildings and their foundations, the dimensions and 
 specifications being given if such is the case. 
 
 54. "Lighting for buildings." 
 
 When electric lighting for any of the buildings is desired, 
 paragraphs a, b, c and d should be filled out. 
 
 60. "Plant." (Power Plant.} 
 
 61. "Engine." 
 70. "Motor." 
 
 85. "Storage battery." 
 
 Definite information must be given as to the power supply. 
 The ampere hour capacity and number of cells of the battery 
 should be specified as well as the capacity of any charging 
 apparatus desired. Data on pages 154 to 159 of this Handbook 
 will be of assistance in determining the proper capacities for 
 the battery and charging apparatus. 
 
 100. "Machine." (Interlocking Machine.) 
 
 While a properly prepared track plan will determine the 
 size and arrangement of levers in the interlocking machine, it 
 will be necessary to specify any spare spaces or spare levers 
 required in the event of this information not being shown on 
 the plan. 
 
 502. "Track circuits." 
 
 The number and arrangement of track circuits to be installed 
 should be shown on the plans or covered in the specification. 
 
 506. "Electric lighting circuits" 
 
 The information called for in this section should be given, 
 attention being called to pages 127 to 130 in this Handbook. 
 
 510. "Special circuits." 
 
 Typical plans of special circuits may be furnished under 
 this section or the circuit requirements stated, in which event 
 the contractor will submit typical proposed circuits with the 
 estimate. Pages 133 to 139 of this Handbook are devoted to 
 Electric Locking circuits, the data being based on the R. S. A. 
 classification of the different types of circuits. 
 
 521. "Size." (Wire and Wiring.} 
 
 The data as to size of wires under paragraph " f " should be 
 given when track circuits are to be installed. 
 
ELECTRIC INTERLOCKING HANDBOOK 415 
 
 ELECTRIC INTERLOCKING LEVERS INSTALLED 
 
 AND UNDER CONTRACT 
 
 JANUARY 1, 1913 
 
 Number Total 
 
 Name of Road of Plants Levers 
 
 Atchinson, Topeka & Santa Fe R'y, 40 1348 
 
 Atlanta, Birmingham & Atlantic R'y, 1 48 
 
 Atlanta Terminal Station, 2 184 
 
 Baltimore & Ohio, 19 880 
 
 Birmingham Terminal Station, 1 144 
 
 Buffalo Creek R. R., 1 84 
 
 Canadian Pacific R'y, 3 40 
 
 Central of Georgia R'y 1 52 
 
 Central R. R. of New Jersey, "1 28 
 
 Chattanooga Union Station Co., 1 120 
 
 Chesapeake & Ohio R'y, 7 212 
 
 Chicago & Alton R. R., 2 108 
 
 Chicago & Eastern Illinois R. R., 4 136 
 
 Chicago & Milwaukee Electric, ........ 1 32 
 
 Chicago & Northwestern R'y, 35 2100 
 
 Chicago & Western Indiana R. R., 1 24 
 
 Chicago, Burlington & Quincy R. R., 7 464 
 
 Chicago Great Western R. R., 5 128 
 
 Chicago, Indianapolis & Louisville R'y (Monon), 1 28 
 
 Chicago, Milwaukee & St. Paul R'y, 10 416 
 
 Chicago, Rock Island & Pacific R'y, 5 494 
 
 Chicago, St. Paul, Minneapolis & Omaha R'y, . 5 80 
 
 Cincinnati, New Orleans & Texas Pacific R'y, . . 6 208 
 
 Cleveland, Cincinnati, Chicago & St. Louis R'y, . 13 556 
 
 Copper Range R. R., 1 40. 
 
 Cumberland Valley R. R., 3 24 
 
 Delaware & Hudson Co., 2 64 
 
 Department of Public Works, British Columbia, 1 28 
 
 Detroit & Toledo Construction Co., 1 32 
 
 Detroit River Tunnel Co., 4 264 
 
 Elgin, Joliet & Eastern R'y, 2 72 
 
 Erie R. R., 11 614 
 
 Galveston, Harrisburg & San Antonio R'y, ... 1 40 
 
 Grand Trunk R'y, 2 60 
 
 Great Northern R'y, 6 200 
 
 Gulf, Colorado & Santa Fe R'y, 1 48 
 
 Houston & Texas Central R. R., 8 248 
 
 Houston Belt & Terminal R'y, 3 140 
 
 Hudson & Manhattan R. R., 10 128 
 
 Illinois Central R. R., 20 824 
 
 Kansas City Terminal R'y, 1 56 
 
 Kentucky & Indiana Terminal R. R., 1 56 
 
 Lake Shore & Michigan Southern R'y, 28 1778 
 
 Lehigh Valley R. R., 9 384 
 
 Long Island R. R., 2 68 
 
 Louisville & Nashville R. R., 4 160 
 
416 GENERAL RAILWAY SIGNAL COMPANY 
 
 Number 
 Name of Road of Plants 
 
 Louisiana R'y & Navigation Co., 1 
 
 Michigan Central R. R., 6 
 
 Missouri Pacific R'y, 1 
 
 Morgan's Louisiana & Texas R. R. & S. S. Co., . 1 
 
 Nashville, Chattanooga & St. Louis R'y, .... 1 
 
 New York Central & Hudson River R. R., . . . 32 
 
 New York, New Haven & Hartford R. R., . . . 3 
 
 Norfolk & Western R'y, 1 
 
 Northern Pacific R'y, 7 
 
 Northwestern Elevated R. R., 1 
 
 Oregon Short Line, 1 
 
 Oregon, Washington R. R. & Navigation Co., . . 2 
 
 Pacific Electric R'y, 4 
 
 Pecos & North Texas Ry., 1 
 
 Pennsylvania Lines West of Pittsburgh, .... 16 
 
 Pennsylvania R. R., 3 
 
 Peoria & Pekin Union R'y, 1 
 
 Pere T arquette R. R., 6 
 
 Pittsburgh & Lake Erie R. R., . 4 
 
 Railway Signal Co. , of Canada (Grand Trunk R'y ) , 1 
 
 San Francisco-Oakland Terminal R'y, 2 
 
 Savannah Union Station, 2 
 
 Southern Indiana R'y, 1 
 
 Southern Pacific Co., 17 
 
 Southern Railway, 1 
 
 Spokane & Inland Empire R.R., 1 
 
 Terminal R. R. Assn. of St. Louis, 6 
 
 Texas & Pacific R'y, 1 
 
 Tidewater & Western R. R 1 
 
 Toledo & Ohio Central R. R., 2 
 
 Toledo R'y & Light Co., 1 
 
 Toledo R'y & Terminal Co 2 
 
 Toronto, Hamilton & Buffalo R'y, 1 
 
 Union Pacific R. R., 6 
 
 Washington, Baltimore & Annapolis Electric R'y, 1 
 
 Western Pacific R'y, 6 
 
 Wisconsin Central R. R., 3 
 
 Grand Total, 440 21,370 
 
INDEX 
 
INDEX 
 
 Alternating 
 A 
 
 Alternating current appliances, 107- 
 
 124. 
 Alternating current relays (see 
 
 relays) . 
 
 Angles, measures of, 388. 
 Apparatus (see under name of mate- 
 rial). 
 Appendix : 
 
 Information for estimating, 413, 
 
 414. 
 Interlocking plants installed, list 
 
 of, 415, 416. 
 Reprint of Preface from Taylor 
 
 (G. R. S.) Catalogue No. 1, 
 
 405-413. 
 Approach locking, 136, 138 (see also 
 
 electric locking). 
 A. R, A. rail sections, 375. 
 Arcs, measures of, 388. 
 Arrester, lightning, 371. 
 A. S. C. E. rail sections, 375. 
 Avoirdupois weight, 388. 
 
 Ballast, definition of grades of, 273. 
 Batteries : 
 
 Primary, caustic soda cell: 
 
 Action of, 285, 287. 
 
 Care of, 287. 
 
 Description of, 285. 
 
 Illustration of, 286. 
 
 R. S. A. cell, 286. 
 
 R. S. A. specifications for, 287, 
 288. 
 
 Symbols for, 351, 359. 
 
 Uses of, 285. 
 Primary, dry cell: 
 
 Care of, 294. 
 
 Description of, 294. 
 
 Symbols for, 351, 359. 
 
 Uses of, 293. 
 Primary, gravity cell: 
 
 Action of, 289. 
 
 Care of, 293. 
 
 Chutes for, 292, 293. 
 
 Coppers for, R. S. A., 291. 
 
 Description of, 289. 
 
 Symbols for, 351, 359. 
 
 Uses of, 288. 
 
 Zinc for, R. S. A., 290. 
 Secondary, lead type storage: 
 
 Broken jars, 153. 
 
 Batteries 
 
 Batteries:' (Con.) 
 
 Secondary, lead type storage: 
 Capacity required for electric 
 
 lighting, 155, 156. 
 Capacity required for function 
 
 operation, 154, 155. 
 Capacity required for G. R. S. 
 
 plants, 154-158. 
 Capacity required for G. R. S. 
 
 plants, table, 158. 
 Capacity required for indica- 
 tors, locks, etc., 156. 
 Capacity required for operating 
 
 switchboard, 155. 
 Capacity, reserve, 156, 157. 
 Cell cover for, 146. 
 Cells, number required for inter- 
 locking plants, 38. 
 Charging apparatus for, 39, 40, 
 
 159-166. 
 
 Charging circuit for, 163. 
 Charging instructions for, 151, 
 
 152. 
 
 Charging switch for, 160. 
 Charging rate of, 146, 159. 
 Cupboards for, 38, 158. 
 Description of, 145. 
 Dimensions of R. S. A. cell, 
 
 146. 
 Discharging, instructions for, 
 
 152. 
 
 Electrolyte for, 146, 148, 149. 
 Formula for determining size of, 
 
 157, 158. 
 Function constants, table of, 
 
 155. 
 
 Housing of, 37, 38. 
 Illustrations <Jf, 37, 38, 145, 
 
 146, 158. 
 ' Important points in care of, 
 
 153, 154. 
 
 Indications of trouble in, 153. 
 Initial charge of, 150. 
 Inspection of, 153. 
 Installation, R. S. A. directions 
 
 for, 148-151. 
 Jar for, 146. 
 
 Large capacity cells for, 151. 
 Location at interlocking plants, 
 
 37. 
 
 Low voltage, uses of, 39. 
 Operation, R. S. A. instructions 
 
 for, 151-154. 
 Pilot cell for, 151. 
 Racks for, 37, 145. 
 
420 
 
 INDEX 
 
 Batteries 
 
 Batteries: (Con.) 
 
 Secondary, lead type storage: 
 Readings of, 153. 
 Reserve capacity required, 156, 
 
 157. 
 
 R. S. A. directions for installa- 
 tion, 148-151. 
 
 R. S. A. instructions for opera- 
 tion of, 151-154. 
 R. S. A. specifications for, 147, 
 
 148. 
 
 Sand tray for, 146. 
 Specifications for, R. S. A., 147, 
 
 148. 
 
 Symbols for, 359. 
 Trouble, indications of, 153. 
 Two plate cells for, 150, 151. 
 Uses at interlocking plants, 38, 
 
 39. 
 
 Voltage of, 38, 39. 
 Weights of cells for, 146. 
 Battery charging apparatus (see 
 
 charging apparatus). 
 Battery chutes: 
 
 Illustrations of, 292, 293. 
 Symbols for, 351. 
 Uses of, 293. 
 Weights of, 367. 
 
 Battery charging switch, 160, 161. 
 Baume's hydrometer, compared 
 
 with specific gravities, 384. 
 Bearing, for high or dwarf signal, 79. 
 Belting, 373, 374. 
 Blades for upper quadrant signals, 
 
 249. 
 Board feet required for trunking, 
 
 315. 
 
 Board measure, table of, 383. 
 Bolts, dimensions of, 380. 
 Bonds, impedance (see impedance 
 
 bonds) . 
 
 Bond wires and channel pins, quan- 
 tities required, 378. 
 Boxes: 
 
 Junction (see junction boxes). 
 Measuring concrete, 323. 
 Relay (see relay boxes). 
 Switch (see switch circuit con- 
 trollers). 
 
 Bracket masts, 243. 
 Bracket posts (see posts). 
 Bridge circuit closers ; 
 Description of, 233, 234. 
 Dimensions of, 233. 
 Operation of, 233, 234. 
 
 Symbols for, 357. 
 Bridge masts, 243. 
 
 Circuits 
 
 Capacity of storage batteries, 154- 
 158 (see also battery, stor- 
 age). 
 Caustic soda cell, 285-288 (see also 
 
 battery, primary). 
 Centigrade temperatures compared 
 
 with Fahrenheit, 392. 
 Channel pins and bond wires, quan- 
 tities required, 378. 
 Charging apparatus, generators, 
 
 driving units, etc.: 
 Capacity required, 159. 
 Circuits for, 163. 
 Description of, 39, 40. 
 Dimensions of, 168, 169. 
 Efficiency of, 159. 
 Floor space, required for, 159, 
 
 169. 
 
 Input, 159. 
 Illustrations of, 39, 40, 42, 43, 
 
 170. 
 
 Installation data for, 159-181. 
 Switchboards for, 40-46. 
 Symbols for, 359. 
 Weights of, 363. 
 Charging rheostat, 40. 
 Charging switch, battery, 160, 161. 
 Charts, manipulation, 102, 103. 
 Check locking, 140, 141. 
 Chutes, battery (see battery chutes). 
 Circuits: 
 
 Approach, indication and sec- 
 tion locking in combination, 
 138. 
 
 Approach locking, 136. 
 Alternating current track, double 
 
 rail, 273. 
 Alternating current track, single 
 
 rail, 114-119. 
 
 Battery charging switch, 161. 
 Charging, simplified, 163. 
 Check locking, 140, 141. 
 Cross protection, 88, 89. 
 Double rail A. C. track, 273. 
 Electric locking: 
 
 Approach, indication and sec- 
 tion locking in combination, 
 138. 
 
 Approach locking, 136. 
 Route locking, 135. 
 Section locking 134. 
 Stick, indication and section 
 locking in combination, 139. 
 Stick locking, 137. 
 Interlocking machine, 88. 
 
INDEX 
 
 421 
 
 Circuits 
 
 Circuits: (Con.) 
 Motor connections: 
 
 Model 2 switch machine, 201. 
 Model 4 switch machine, 209. 
 Operating: 
 
 Model 2 and 3 dwarf signals, 83, 
 
 84. 
 
 Model 2A high signal, 22-24. 
 Model 2 and 4 switch machines, 
 
 19-22. 
 
 Switchboards, 40-46. 
 Pole changer: 
 
 Model 2 switch machine, 203. 
 Model 4 switch machine, 210. 
 Route locking, 135. 
 Section locking, 134. 
 Signal: 
 
 Description of, 22-24. 
 
 Model 2 or 3 solenoid dwarf, 
 
 84. 
 Model 2 solenoid dwarf, one 
 
 arm, typical, 260. 
 Model 2 solenoid dwarf, two 
 
 arm, typical, 261. 
 Model 3 solenoid dwarf, typi- 
 cal, 262. 
 
 Model 2 A, two position, non- 
 automatic, simplified, 23. 
 Model 2A, two position, non- 
 automatic, typical, 71, 254, 
 255. 
 
 Model 2A, two position, semi- 
 automatic, typical, 73, 256- 
 259. 
 
 Single rail A. C. track, 114- 
 119. 
 
 Stick, indication and section 
 
 locking in combination, 139. 
 Stick locking, 137. 
 Switchboard : 
 
 Description of, 40-46. 
 Combination power and opera- 
 ting, 180. 
 Operating, 181. 
 Operating, simplified diagram 
 
 for, 45. 
 
 Power, 176-178. 
 Power, simplified diagram for, 
 
 43. 
 Switch machine: 
 
 Description of, 19-22. 
 Double switch lever, 228. 
 Model 2 or Model 4, 61. 
 Model 2 or Model 4, simplified, 
 
 20. 
 
 Model 2, typical, 226. 
 Model 4, typical, 227. 
 
 Concrete 
 
 Circuits: (Con.) 
 Switch machine: 
 
 Motor connections, Model 2, 
 
 201. 
 Motor connections, Model 4, 
 
 209. 
 
 Pole changer, Model 2, 203. 
 Pole changer, Model 4, 210. 
 Symbols for, 354-359. 
 Testing, for pick-up and drop- 
 away of D. C. line relay, 276. 
 Testing, for pick-up and drop- 
 away of D. C. track relay, 
 276. 
 Testing, for resistance of grounds, 
 
 372. 
 Testing, for resistance of relay 
 
 contacts, 276. 
 Track: 
 
 Alternating current, double 
 
 rail, 273. 
 Alternating current, single rail, 
 
 114-119. 
 
 Written, 331-339. 
 Circuit closers, bridge, 233, 234. 
 Circuit controllers: 
 
 Nomenclature for, 334-336. 
 Switch (see switch circuit con- 
 trollers) . 
 
 Symbols for, R. S. A., 356-358. 
 Circular measure, 388. 
 Clearance diagrams: 
 
 Model 2A dwarf signal and third 
 
 rail, 244. 
 
 Model 2 and Model 4 switch ma- 
 chines, 214. 
 Model 4 switch machine and third 
 
 rail, 215. 
 Clips, rail, 229. 
 Closers, bridge circuit, 233. 
 Common return or main common 
 wire, 19, 22, 60, 70, 83, 93, 
 309. 
 
 Concrete, Portland Cement: 
 Box for measuring, 323. 
 Cautions in use of, 322, 323. 
 Consistency of, 321. 
 Foundations (see foundations). 
 Mixing by hand, 322. 
 Mixing by machine, 322. 
 Proportions of material for, 321. 
 Specifications, R. S. A. for: 
 Cement, 325. 
 Consistency, 326. 
 Density of ingredients, 326. 
 Disposition, 327. 
 Facing, 327. 
 
422 
 
 INDEX 
 
 Concrete 
 
 Concrete: (Con.) 
 
 Specifications, R. S. A. for: 
 Finishing, 327. 
 Forms, 326. 
 Freezing weather, 328. 
 General, 325. 
 Gravel, 325. 
 Measures, 325. 
 Mixing, 326. 
 
 Reinforced concrete, 328. 
 Sand, 325. 
 Stone, 325. 
 Water, 325. 
 Waterproofing, 328. 
 Storing of, 321. 
 Volumes of material for, 324. 
 Controllers, circuit (see circuit con- 
 trollers). 
 Control wire for signals, 22, 70, 83, 
 
 308. 
 Control wire for switches, 19, 60, 
 
 308. 
 
 Cooling tank (see tanks). 
 Copper-clad wire tables, 307 (see 
 
 also wire). 
 Coppers for gravity primary battery, 
 
 291. 
 Copper wire tables, 306, 307 (see 
 
 also wire) . 
 Cross protection : 
 Advantages of, 26. 
 Apparatus for, 88-96. 
 Circuit breaker, individual, 95. 
 Circuit breaker, switchboard, 90. 
 Circuits for, 88, 89. 
 Description of, 24-26, 88-96. 
 Operation of circuit breaker for, 
 
 91, 92. 
 
 Polarized relays for, 92, 93. 
 Principles of, 89. 
 Safeguards, 93. 
 Sectionalizing of plants for, 93, 
 
 94. 
 
 Tests for, 94, 96. 
 
 Uses of, 24-26. 
 
 Cubic measure, 388. 
 
 Cupboards, battery housing, 38, 158. 
 
 Cycle of movements: 
 
 Model 2 switch machine, 212. 
 Model 4 switch machine, 13. 
 
 Detector bars: 
 
 Motion plates for, 229. 
 Rail clips for, 229. 
 Weights of layouts for, 365. 
 
 Electro-pneumatic 
 
 Development of electric interlock- 
 ing, 6. 
 Diagrams : 
 
 Illuminated track, 105, 106. 
 Track, 102, 103. 
 
 Distances, shipping, between cities 
 of U. S. and Canada, map of, 
 368. 
 
 Direct current relays (see relays). 
 Direct current generators (see gen- 
 erators) . 
 Dog chart, 55. 
 Dry cell, 293, 294 (see also battery, 
 
 primary) . 
 Dry measure, 388. 
 Dwarf signals (see signals mechan- 
 isms) . 
 
 Dynamic indication: 
 Advantages of, 16, 24. 
 Circuits for, 20, 23, 61, 71, 73. 
 Description of, 15, 21, 24, 60, 71, 
 
 74. 
 
 Safety of, 24. 
 Uses of, 16, 24. 
 
 Electric interlocking (see inter- 
 locking) . 
 Electric interlocking machines (see 
 
 interlocking machine). 
 
 Electric interlocking system, 15-28. 
 
 Electric interlocking system (reprint 
 
 from Catalogue No. 1 , Taylor 
 
 Signal Co.) , 405-413. 
 
 Electric lighting, 127-130 (see also 
 
 lighting) . 
 Electric locking: 
 
 Approach locking, 136. 
 
 Circuits for, 134-139. 
 
 Combination of basic forms of, 
 138, 139. 
 
 Definitions of, 133. 
 
 Description of, 133-139. 
 
 Development of, 133. 
 
 Indication locking, 137, 138. 
 
 Route locking, 135, 136. 
 
 Screw release for, 134. 
 
 Section locking, 134, 135. 
 
 Sectional route locking, 135, 136. 
 
 Stick locking, 137. 
 
 Time release for, 134. 
 Electric time release, 134. 
 Electrolyte for storage batteries: 
 
 Specific gravity of, 148. 
 
 Weight of, 146. 
 Electro-pneumatic interlocking, 5, 6. 
 
INDEX 
 
 423 
 
 Engines 
 
 Engines, gasoline: 
 Belting for, 373, 374. 
 Cooling tank, connections for, 
 
 170, 171, 175. 
 
 Cooling tank, location of, 171. 
 Description of, 170-172. 
 Dimensions of, 169. 
 Foundations for, 169. 
 Gasoline tank for, 171, 174, 175. 
 Horse power of, 159, 169, 174. 
 Illustrations of, 170. 
 Installation data for, 169, 171, 
 
 174. 
 
 Location of, 171. 
 Specifications, R. S. A., for, 174, 
 
 175. 
 
 Speed of, 169, 174. 
 Starting, 171, 172. 
 Stopping, 172. 
 
 Tanks for, 170, 171, 174, 175. 
 Troubles, 172-174. 
 
 Cannot crank, 173. 
 
 Carburetion, 172. 
 
 Ignition, 172. 
 
 Loss of compression, 172, 173. 
 
 Loss of power, 173, 174. 
 
 Mechanical difficulties, 173. 
 Water connections for, 170. 
 Estimates, information to be fur- 
 nished by R. R., 413, 414. 
 
 Fahrenheit temperatures compared 
 
 with Centigrade, 393. 
 First interlocking installation in 
 
 U. S. A., 5. 
 
 Fluxes for soldering and welding, 299. 
 Foundations : 
 
 Bracket post, 251. 
 
 Concrete for (see concrete). 
 
 Gasoline engine, 169. 
 
 Ground signal mast, 252. 
 
 Model 2 one arm dwarf signal, 253. 
 
 Model 2 two arm dwarf signal, 
 253. 
 
 Model 2A dwarf signal, 253. 
 
 Model 3 dwarf signal, 253. 
 
 Gasoline engines, 169-175 (see also 
 
 engines) . 
 
 Gasoline tanks (see tanks). 
 Gears: 
 
 Clearance of, Model 2A signal, 78. 
 
 Formula for, 372. 
 
 Speed of, 372. 
 
 Indicating 
 
 Generators, direct current: 
 
 Capacity of, 159, 169. 
 
 Charging circuits for, 163. 
 
 Description of, 39, 162. 
 
 Dimensions of, 169. 
 
 Engines for driving, 159, 169. 
 
 Failure to build up, 166. 
 
 Fitting brushes to, 165. 
 
 Foundation for, 169. 
 
 General instructions for, 164, 
 165. 
 
 Illustrations of, 39. 
 
 Installation of, 162-169. 
 
 Maintenance of, 163-166. 
 
 Operation of, 162-164. 
 
 Setting up, 162, 169. 
 
 Shutting down, 164. 
 
 Speed of, 169. 
 
 Specifications, R. S. A. for, 166, 
 167. 
 
 Starting, 162, 163. 
 
 Symbols for, 359. 
 
 Uses of, 39. 
 
 Voltage of, 162. 
 
 Weights of, 363. 
 
 Gravity cell, 288-293 (see also bat- 
 tery, primary) . 
 Grounds, circuit for testing, 372. 
 
 Hanger irons for transformers, 279. 
 High Signals (see also signal mech- 
 anisms) : 
 
 Illustrations of, 17, 22, 25, 81. 
 Masts for, 243. 
 Spacing of arms for, 243. 
 Symbols for, 348, 349. 
 Weights of, 365, 366. 
 Horse power of gasoline engines, 
 
 159, 169, 174. 
 Hydrometer, Baume's, compared 
 
 with specific gravities, 384. 
 Hydro-pneumatic interlocking, 5. 
 
 Illuminated track diagrams, 105, 
 
 106. 
 Impedance bonds: 
 
 Description of, 120, 121. 
 
 Dimensions of, 120, 121. 
 
 Layouts for, 120, 121. 
 
 Symbols for, 350. 
 
 Weights of, 367. 
 
 Incandescent lamps (see lamps). 
 Indicating relays, alternating cur- 
 rent (see relays). 
 
424 
 
 INDEX 
 
 Indication 
 
 Indication, dynamic (see dynamic 
 
 indication) . 
 Indication locking, 137-139 (see 
 
 also electric locking). 
 Indication magnets: 
 Energy data for, 194. 
 Illustrations of, 51, 56. 
 Resistance of, 194. 
 Indication selector, 58. 
 Indicators: 
 
 Alternating current: 
 
 Description of, 111, 112. 
 Dimensions of, 270. 
 Energy data for, 271. 
 Symbols for, 354, 355. 
 Weights of, 366, 367. 
 Direct current: 
 
 Battery capacity required for, 
 
 156, 157. 
 
 Description of, 103-105. 
 Dimensions of, 268. 
 Energy data for, 265, 269. 
 Illustrations of, 103-105. 
 Resistance of, 265, 269 
 Symbols for, 354, 355. 
 Uses of, 103-105. 
 Weights of, 366. 
 Individual return wire, 94. 
 Installation data (see under name 
 
 of apparatus) . 
 Installation tools, 369, 370. 
 Instructions, installation and main- 
 tenance (see under name of 
 apparatus). 
 Interlocking, introductory article 
 
 on: 
 
 Electric, G. R. S. system of: 
 Applicability of, 10-12. 
 At what leverage is it economi- 
 cal to install, 7. 
 Average sales of G. R. S. plants, 
 
 11. 
 
 Comparison of safety of, 9, 10. 
 Cost of maintenance of, 8, 9. 
 Developed by, 6. 
 Distances functions may be 
 
 operated from, 10. 
 Effect of climatic conditions on, 
 
 10, 11. 
 
 Exploited by, 6. 
 Number of levers installed, 7. 
 Number of plants installed, 6, 7. 
 Predictions as to future instal- 
 lations of, 11, 12. 
 Progress of, 6, 7. 
 Proportion of plants installed 
 which are G. R. S., 6, 7. 
 
 Interlocking 
 
 Interlocking, introductory article 
 
 on: (Con.) 
 
 Electric, G. R. S. system of: 
 Reasons for adoption of, 8-11. 
 Safety of, 8, 11. 
 Size of installations of, 11. 
 Use in automatic territory of, 9. 
 Use of track diagrams with, 11. 
 Where used, 6, 7, 11. 
 Electro-pneumatic : 
 
 Installation, date of first, 5, 6. 
 Installed at, first, 6. 
 Plants installed, number of, 6. 
 Hydro-pneumatic : 
 
 Installation at, first, 5. 
 Invention of, date of, 5. 
 Plants installed, number of, 5, 
 
 6. 
 Mechanical : 
 
 Class of maintainers for, 8. 
 Comparison of safety of, 9, 10. 
 First experimental installation 
 
 in U. S. A., date of, 5. 
 Installation in U. S. A., by, 
 
 first, 5. 
 
 Installation in U. S. A., loca- 
 tion of first, 5. 
 Installation of, first important, 
 
 5. 
 
 Inventors of, 5. 
 Latch locking, first use of, 5. 
 Limitations of, 5. 
 Origin of, 5. 
 
 Patents, first granted, 5. 
 Interlocking machine, electric: 
 Accessories for, 58, 59. 
 Arrangements of beds for, 190, 
 
 191. 
 
 Cabinets, length of, 190, 191. 
 Circuit breakers for, individual, 
 
 93-95. 
 
 Circuits for, 88. 
 Control of, 47-53. 
 Description of, 47-59. 
 Dimensions of, 186-191. 
 Dog chart for, 55. 
 Energy data for indication mag- 
 nets, 194. 
 
 Energy data for lever locks, 195. 
 Features of, 47-49. 
 Frame for, 53. 
 
 Illustrations of, 18, 43, 48, 49, 52. 
 Indication magnets, operating 
 
 data for, 194. 
 Indication selector for, 58. 
 Individual circuit breakers for, 
 93-95. 
 
INDEX 
 
 425 
 
 Interlocking 
 
 Interlocking machine, electric: 
 
 (Con.) 
 
 Installation data for, 185-195. 
 Lamp cases and number plates 
 
 for, 57. 
 
 Legs, number required and spac- 
 ing, 190, 191. 
 Length of, 190, 191. 
 Lever, description of, 56, 57. 
 Lever, illustration of, 51, 56. 
 Lever lock for, 58, 195. 
 Lever, operation of, 49-53. 
 Locking for, 53-56. 
 Locking plates and locking, 53, 
 
 56. 
 
 Maintenance of, 188, 189. 
 Mechanical time release for, 58, 
 
 59. 
 
 Notching, for lever locks, 192-194. 
 Number of legs required for, 190. 
 
 191. 
 
 Number plates for, 57 
 Operation of signal lever, 50, 53. 
 Operation of switch lever, 49, 50. 
 Polarized relay for, 57, 58, 92, 93. 
 Resistance of indication magnets 
 
 for, 194. 
 
 Safeguards of, 47-49. 
 Safety features of, 4719. 
 Shipment of, 185. 
 Spacing of legs for, 190, 191. 
 Storing of, 185. 
 Terminal boards for, 57. 
 Testing of, 94, 96, 188, 194. 
 Time release for, 58, 59. 
 Unit lever type, description of, 
 
 53-58. 
 
 Uses of, 18, 19. 
 Weights of, 363, 364. 
 Wiring of, typical, 88. 
 Interlocking stations: 
 
 Arrangement of apparatus in, 33. 
 Construction data, 35. 
 Description of, 31-36. 
 Diagrams of, 32, 34, 36. 
 Illustrations of, 31, 33, 35. 
 Sizes of, 31, 33. 
 Symbols for, 352. 
 
 Joints in wire, 298-304. 
 Junction boxes: 
 
 Illustrations of, 316. 
 
 Nails required for, 317. 
 
 Symbols for, 351. 
 
 Weights of, 367. 
 
 Locking 
 L 
 
 Lamps, incandescent (see also 
 
 lighting). 
 
 Ampere hours per signal, 155, 156. 
 Arrangement for signal lighting, 
 
 128. 
 
 Power required for, 127. 
 Symbols for, 359. 
 Types used in signal lighting, 127. 
 Layouts: 
 
 Detector bar, weights of, 365. 
 Impedance bond, 120, 121. 
 Switch, 218-225 (see also switch 
 
 layouts) . 
 Lead type storage batteries (see 
 
 batteries, secondary). 
 Levers : 
 
 Cross connection wiring for 
 
 double switch, 228. 
 Double switch, wiring of, 228. 
 Notches for lever locks, 192-194. 
 Signal: 
 
 Description of, 50, 53, 56, 57. 
 Operation of, 50, 53. 
 Switch: 
 
 Cross connection wiring for 
 
 double, 228. 
 
 Description of, 49, 50, 56, 57. 
 Illustrations of, 51, 56. 
 Operation of, 49, 50. 
 Wiring of double lever, 228. 
 Lever locks (see locks). 
 Lighting, electric signal: 
 
 Ampere hours required for, 155, 
 
 156. 
 
 Bulbs for, 127, 128. 
 Capacity of battery for, 155, 156. 
 Economy effected, 127. 
 Formula for, 156, 157. 
 Lamps, incandescent, 127, 128. 
 Power required for, 127, 155, 
 
 156. 
 
 Precautions, 129. 
 Recommendations for, 130. 
 Reserve power for, 128, 129. 
 Source of power for, 128, 129. 
 When economical to use, 127. 
 Lighting panels (see panels). 
 Lightning arrester, 371. 
 Limitation of mechanical inter- 
 locking, 5. 
 
 Linear measure, 388, 
 Liquids: 
 
 Measure of, 389. 
 Specific gravity of, 385 
 Locking, check, 140, 141. 
 
426 
 
 INDEX 
 
 Locking 
 
 Locking, electric (see electric lock- 
 ing)- 
 Locking plates and locking, 53- 
 
 56. 
 
 Locking sheet, 54. 
 Locks, lever: 
 
 Application to lever, 192-194. 
 
 Cutting of notches for, 192-194. 
 
 Description of, 58. 
 
 Dimensions of, 195. 
 
 Energy data for, 195. 
 
 Illustration of, 195. 
 
 Installation data for, 192-195. 
 
 Notching of levers for, 192-194. 
 
 Specifications for, 192-194. 
 
 Symbols for, 354. 
 
 Test for clearance of, 193, 194. 
 
 Machines : 
 
 Interlocking (see interlocking ma- 
 chine) . 
 
 Signal (see signal mechanism). 
 
 Switch (see switch mechanism). 
 
 Magnets, indication (see indication 
 
 magnets) . 
 
 Main common or common return 
 wire, 19, 22, 60, 70, 83, 93, 
 309. 
 
 Maintenance (see under name of ap- 
 paratus) . 
 
 Maintenance tools, 369, 370. 
 Manipulation charts, 102, 103. 
 Map of shipping distances between 
 cities of U. S. and Canada, 
 368. 
 Masts, R. S. A. signal: 
 
 Bracket, dimensions of, 243. 
 Bridge, dimensions of, 243. 
 Foundations for, 251, 252. 
 Ground, dimensions of, 243. 
 Measures and weights: 
 
 French equivalents of, 390, 391. 
 Metric, 390, 391. 
 Tables of, 388, 389. 
 Measuring box for concrete, 323. 
 Mechanical interlocking (cee inter- 
 locking, mechanical). 
 Mechanical time release, 58, 59. 
 Mechanism : 
 
 Signal (see signal mechanism) . 
 Switch (see switch mechanism) . 
 Mercury arc rectifiers: 
 Input for, 159. 
 Voltage requirements of, 159. 
 
 Motor 
 
 Metals: 
 
 Fluxes for soldering and welding, 
 
 299. 
 
 Specific gravities of, 387. 
 Weights of, 387. 
 
 Metric measure system, 390, 391. 
 Model 2A signal (see signal mech- 
 anism) . 
 Model 2 dwarf signal (see signal 
 
 mechanisms) . 
 Model 3 dwarf signal (see signal 
 
 mechanisms) . 
 Model 2 switch machine (see switch 
 
 mechanisms). 
 Model 4 switch machine (see switch 
 
 mechanisms) . 
 Motion plates, 229. 
 Motors : 
 
 Speed of, 168. 
 
 Starting panels for, 181. 
 
 Switch: 
 
 Connection diagrams for, 201, 
 
 209. 
 Cycle of movements of, 212, 
 
 213. 
 
 Maintenance of, 206, 211. 
 Symbols for, 359. 
 Voltage for, operating, 159, 
 
 162. 
 Motor generators: 
 
 Employing A. C. motor: 
 Floor space required, 159. 
 Illustration of, 42. 
 Input, 159. 
 Symbols for, 359. 
 Employing D. C. motor: 
 Capacity of, 168. 
 Description of, 39, 40. 
 Dimensions of, 168. 
 Failure to build up, 166. 
 Fitting brushes to, 165. 
 Floor space required for, 159, 
 
 168. 
 General instructions for, 164, 
 
 165. 
 
 Illustrations of, 40, 43. 
 Input, 159. 
 
 Installation data for, 162-168. 
 Maintenance of, 163-166. 
 Setting up, 162. 
 Shutting down, 164. 
 Speed of, 168. 
 Starting of, 162, 163. 
 Symbols for, 359. 
 Weights of, 363. 
 Motor starting panels, 181. 
 
INDEX 
 
 427 
 
 Nails 
 
 N 
 Nails: 
 
 Amount required for junction 
 
 boxes, 317. 
 Amount required for trunking, 
 
 317. 
 
 Sizes of, 382. 
 Weights of, 382. 
 
 Number plates, interlocking ma- 
 chines, 57. 
 
 O 
 
 Oiling diagrams: 
 
 Dwarf bearing, Model 2 A signal, 
 
 240. 
 Mechanism, Model 2A signal, 238. 
 
 Operating data (see under name of 
 apparatus) . 
 
 Operating mechanisms (see under 
 name of mechanism). 
 
 Operating switchboards (see switch- 
 board). 
 
 Paint: 
 
 Amount required for trunking, 
 
 374. 
 
 Application of, 374. 
 Specifications, R. S. A. for, 374. 
 Panels: 
 Lighting : 
 
 Dimensions of, 182. 
 Switches for, 182. 
 Weights of, 363. 
 Motor-starting, 181. 
 Pilot cell, 151 (see batteries, sec- 
 ondary) . 
 Pipe, wrought iron, dimensions of, 
 
 381. 
 
 Piping for gasoline engine: 
 Cooling tank, 170, 175. 
 Gasoline tank, 171, 175. 
 Running water, 170. 
 Plan, track, 54. 
 Plants, power, G. R. S. (see power 
 
 plants) . 
 
 Plates, motion, 229. 
 Polarized relays: 
 
 Description of, 57, 58, 92, 93. 
 Functions of, 25, 92. 
 Illustrations of, 58, 92, 186, 189. 
 Pole changer: 
 
 Model 2 switch machine: 
 Adjustment of, 202-205. 
 Connections for, 202, 203 
 
 R. S. A. Specifications 
 
 Pole changer: (Con.) 
 Model 2 switch machine: 
 Illustration of, 64. 
 Installation data for, 202-205. 
 Maintenance of, 206. 
 Movement for, 202. 
 Operation of, 63, 64. 
 Testing of, 204, 205. 
 Wiring for, 203. 
 Model 4 switch machine: 
 Description of, 68. 
 Illustration of, 68. 
 Maintenance of, 211. 
 Operation of, 68. 
 Wiring for, 210. 
 
 Polyphase relays (see relays A. C.). 
 Posts, bracket: 
 
 Foundation for, 251. 
 Masts for, 243. 
 Weights of, 365. 
 
 Power interlocking (see interlock- 
 ing). 
 Power plants: 
 
 Batteries for, 38, 39 (see also bat- 
 teries) . 
 
 Charging apparatus for, 39, 40 
 (see also charging apparatus). 
 Composition of, 37. 
 Description of, 37-40. 
 Illustrations of, 42, 43. 
 Location of, 37. 
 Switchboards for, 40-46 (see also 
 
 switchboards) . 
 
 Power switchboards (see switch- 
 boards) . 
 Primary batteries, 285-294 (see 
 
 also batteries, primary). 
 Protection, cross (see Across protec- 
 tion) . 
 Pulleys, 372. 
 
 Racks, battery, illustrations of, 37, 
 
 145. 
 Rail clips, E. Z. motion plate type, 
 
 229. 
 
 Rail sections, dimensions of, 375. 
 R. S. A. specifications for: 
 
 Caustic soda primary cell, 287, 
 
 288. 
 
 Concrete, 325-328. 
 Copper for gravity cell, 291. 
 Electric generator, 166, 167. 
 Electric interlocking, extracts 
 
 from: 
 Painting, 374. 
 
428 
 
 INDEX 
 
 K. S. A. Specifications 
 
 R. S. A. Specifications for: (Con.) 
 Electric interlocking, extracts 
 
 from: 
 Trunking, junction boxes and 
 
 supports, 312, 313. 
 Wire and wiring, 297-299. 
 Gasoline engine, 174, 175. 
 Lead type storage battery, 147- 
 
 154. 
 Portland cement concrete, 325- 
 
 328. 
 Principles of signal indications, 
 
 343. 
 
 Signaling practice, 343-347. 
 Symbols, 348-359. 
 Voltage ranges, 282. 
 Zinc for gravity cell, 290. 
 R. S. A. standard apparatus: 
 Battery chutes, 292. 
 Battery jar, sand tray and cover, 
 
 146. 
 Blades for upper quadrant signals, 
 
 249. 
 
 Bracket post masts, 243. 
 Bridge signal masts, 243. 
 Caustic soda primary cell, 286. 
 Coppers for gravity battery, 291. 
 Foundation for bracket post, 251. 
 Foundation for ground signal 
 
 mast, 252. 
 
 Ground signal masts, 243. 
 Spectacle, Design "A," 248,250. 
 Spectacle, Design "B," 248. 
 Zinc for gravity battery, 290. 
 R. S. A. symbols: 
 
 Charging apparatus, 359. 
 Circuit controllers, 356-358. 
 Circuit plans, 354-359. 
 Instruments, 357-359. 
 Location, 350-353. 
 Relays, indicators and locks, 354, 
 
 355. 
 
 Signals, 348, 349. 
 Switches, derails, etc., 352, 353. 
 Track plans, 348-353. 
 Reactance bonds (see impedance 
 
 bonds). 
 Relays: 
 
 Alternating current: 
 Boxes for, 274, 275. 
 Description of, 109-113. 
 Dimensions of, 270, 272. 
 Energy data for, 271, 273, 274 
 Illustrations of, 110, 112. 
 Selection of, 109, 110. 
 Types of, 110-112. 
 Weights of, 366. 
 
 Belays 
 
 Relays: (Con.) 
 Boxes for: 
 
 Dimensions of, 274, 275. 
 
 Weights of, 367. 
 Dimensions of, 266-272. 
 Direct Current: 
 
 Boxes for, 275. 
 
 Dimensions of, 266, 268. 
 
 Energy data for, 265, 267. 
 
 Illustrations of, 100, 101. 
 
 Resistance of, 265, 267. 
 
 Testing of, 276. 
 
 Weights of, 366. 
 Energy data for, 265-274. 
 Indicating: 
 
 Dimensions of, 270. 
 
 Energy data for, 271. 
 
 Weights of, 366. 
 Model l.D. C.: 
 
 Boxes for, 275. 
 
 Energy data for, 265. 
 
 Resistance of, 265. 
 
 Test for pick-up and drop- 
 away, 276. 
 
 Test for resistance of contacts, 
 276. 
 
 Weights of, 366. 
 Model 2, Form A, Polyphase: 
 
 Boxes for, 274. 
 
 Description of, 110, 111. 
 
 Dimensions of, 272. 
 
 Energy data for, 271-274. 
 
 Illustration of, 110. 
 
 Test for resistance of contacts, 
 276. 
 
 Weights of, 366. 
 Model 2, Form B, A. C. : 
 
 Boxes for, 275. 
 
 Description of, 111. 
 
 Dimensions of, 270. 
 
 Energy data for, 271. 
 
 Illustration of, 112. 
 
 Test for resistance of contacts, 
 276. 
 
 Weights of, 366. 
 Model 3, Form B, A. C.: 
 
 Boxes for, 275. 
 
 Description of, 111, 112. 
 
 Dimensions of, 270. 
 
 Illustration of, 112. 
 
 Test for resistance of contacts, 
 276. 
 
 Weights of, 366. 
 Model 9, D. C.: 
 
 Boxes for, 275. 
 
 Dimensions of, 266. 
 
 Energy data for, 267. 
 
INDEX 
 
 429 
 
 Belays 
 
 Relays: (Con.) 
 Model 9, D. C.: 
 
 Illustrations of, 101. 
 Resistance of, 267. 
 Test for pick-up and drop- 
 away, 276. 
 Test for resistance of contacts, 
 
 276. 
 
 Weights of, 366. 
 Model Z, Form B. A. C. : 
 Boxes for, 275. 
 Description of, 112. 
 Dimensions of, 270. 
 Energy data for, 271. 
 Illustration of, 112. 
 Test for resistance of contacts, 
 
 276. 
 
 Weights of, 366. 
 Motor, Three Position, D. C.: 
 Boxes for, 275. 
 Description of, 98, 100, 101. 
 Dimensions of, 268. 
 Energy data for, 267, 268. 
 Illustration of, 100. 
 Test for resistance of contacts, 
 
 276. 
 
 Weights of, 366. 
 Polarized (see polarized relay). 
 Symbols for, 354, 355. 
 Testing: 
 
 Pick-up and drop-away of, 276. 
 
 Resistance of contacts for, 276. 
 
 Three Position D. C. Motor (see 
 
 Relay, Motor) : 
 Relay boxes: 
 
 Dimensions of, 274, 275. 
 Symbols for, 351. 
 Weights of, 367. 
 Release, time (see time release) . 
 Route locking, 135, 136 (see also 
 electric locking). 
 
 S 
 
 Safeguards: 
 
 Cross protection system, 24-26, 
 
 93. 
 
 Dynamic indication, 24. 
 G. R. S. system, 24-26. 
 Interlocking machine, 47-49. 
 Switch operating mechanisms, 
 
 61-63. 
 
 Tests for cross protection, 94, 96. 
 Safety of G. R. S. electric interlock- 
 ing: 
 
 Comparison with mechanical, 8. 
 Cross protection, 89. 
 
 Signals 
 
 Safety of G. R. S. electric interlock- 
 ing: (Con.) 
 Dynamic indication, 24. 
 Features important to, 15. 
 Test of, 94, 96. 
 Sand: 
 
 Concrete, 325. 
 Measuring box for, 323. 
 Quantities of, for concrete, 324. 
 Specific gravities of, 386. 
 Weights of, 386. 
 Screw release (see time release) . 
 Secondary batteries (see batteries, 
 
 secondary). 
 Sectionalizing of G. R. S. plants, 93, 
 
 94. 
 Sectional route locking, 135, 136 
 
 (see also electric locking) . 
 Section locking, 134, 135 (see also 
 
 electric locking). 
 Selector, indication, 58. 
 Semaphore spectacles (see specta- 
 cles). 
 
 Shipping distances between cities of 
 U. S. and Canada, map of, 
 368. 
 Shipping weights, 363-367 (see also 
 
 weights) . 
 Signaling practice: 
 
 American, trend of, 11. 
 Definitions of, 343-347. 
 Principles of signal indications, 
 
 343. 
 R. S. A. recommendations for, 
 
 343. 
 Signals: 
 
 Automatic block: 
 
 Basis of adoption in America, 
 
 9. 
 
 Percentage of American Rail- 
 ways signaled, 9. 
 Type first used, 9. 
 Blades for upper quadrant, 249. 
 Bracket masts for, 243. 
 Bridge masts for, 243. 
 Control wire for, 22, 70, 83, 308. 
 Dwarf (see signal mechanisms). 
 Electric lighting for, 127-130. 
 Foundations for, 251-253. 
 Ground masts for, 243. 
 Illustrations of dwarf, 16, 74, 75, 
 
 83, 86. 
 Illustrations of high, 17, 22, 25, 
 
 81. 
 
 Indications, principles of, 343. 
 Interlocking (see signal mechan- 
 
 3). 
 
430 
 
 INDEX 
 
 Signals 
 
 Signals: (Con.} 
 
 Mechanisms (see signal mechan- 
 isms). 
 
 Spectacles for, 248. 
 Symbols for, 348, 349. 
 Weights of, 365, 366. 
 Signal blades, 249. 
 Signal lighting, 127-130 (see also 
 
 lighting) . 
 Signal mechanisms: 
 
 Circuits for (see circuits, signal). 
 Control wire for, 22, 70, 83, 308. 
 Dwarf, solenoid (see solenoid 
 
 dwarf signals). 
 
 Dynamic indication for (see dyna- 
 mic indication). 
 Foundations for, 251-253. 
 Installation data: 
 
 Adjustments, 237, 239, 241. 
 
 Dimensions, 242, 245-247. 
 
 Foundations for, 251-253. 
 
 Lubrication of, 239. 
 
 Masts for, 243. 
 
 Method of taping wires to, 244. 
 
 Storing of, 237. 
 
 Spectacle adjustment for, 239. 
 
 Tests of, 240. 
 Maintenance of: 
 
 Adjustments, 237, 241. 
 
 Lubrication, 239, 241. 
 
 Oiling diagrams, for, 238, 240. 
 
 Spectacle adjustments for, 239. 
 
 Tests for, 240. 
 Masts for, 243 
 Model 2 A non-automatic: 
 
 Adjustment of, 237, 241. 
 
 Circuits for, 23, 71, 254, 255. 
 
 Clamp bearing for, 79. 
 
 Control of, 70-72. 
 
 Control wire for, 22, 70, 308. 
 
 Description of, 22-24, 77-79. 
 
 Description of circuits for, 
 22-24. 
 
 Dynamic indication, advan- 
 tages of, 24. 
 
 Dwarf bearing for, 79. 
 
 Gears, clearance of, 78. 
 
 Illustration of, 76. 
 
 Installation of, 237. 
 
 Length of control wire for, 308. 
 
 Lever operation for, 50, 53. 
 
 Lubrication of, 239. 
 
 Maintenance of, 241. 
 
 Method of taping .wires to, 244. 
 
 Names of parts for. 76. 
 
 Oiling diagrams for, 238, 240. 
 
 Operating data for, 241. 
 
 Signals 
 
 Signal Mechanisms : (Con.) 
 Model 2A, non-automatic : 
 
 Simplified circuits for, 23. 
 
 Size of control wire for, 308. 
 
 Spectacle adjustment for, 239. 
 
 Storing of, 237. 
 
 Tests for, 240. 
 
 Typical circuits for, 71, 254, 
 255. 
 
 Weights of, 366. 
 Model 2A, semi-automatic: 
 
 Adjustment of, 237, 241. 
 
 Circuits for, 73, 256-259. 
 
 Clamp bearing for, 79. 
 
 Control of, 72-75. 
 
 Control wire for, 22, 83, 308. 
 
 Description of, 81, 82. 
 
 Dimensions of, 242. 
 
 Dwarf bearing for, 79 
 
 Dynamic indication advantages 
 of, 24. 
 
 Gears, clearance of, 78. 
 
 Illustrations of, 80, 81. 
 
 Indication spring attachment, 
 82. 
 
 Installation of, 237. 
 
 Length of control wire for, 
 308. 
 
 Lever operation for, 50-53. 
 
 Lubrication of, 239. 
 
 Maintenance of, 241. 
 
 Method of taping wires to, 
 244. 
 
 Names of parts for, 80. 
 
 Oiling diagram lor, 238. 
 
 Operating data for, 241. 
 
 Size of control wire for, 308. 
 
 Spectacle adjustment for, 239. 
 
 Spring attachment, indication, 
 82. 
 
 Storing of, 237. 
 
 Tests for, 240. 
 
 Typical circuits for, 73, 256- 
 259 
 
 Weights of, 366. 
 
 Model 3, operating data for, 241. 
 Model 7, operating data for, 241. 
 Motor driven (see Model 2A sig- 
 nals). 
 
 Operating and indicating circuits, 
 
 description of, 22-26, 70-75. 
 
 Solenoid dwarf (see solenoid 
 
 dwarf) . 
 
 Symbols for, 348, 349. 
 Typical circuits for (see circuits). 
 Types of, 70. 
 Weights of, 365-366. 
 
INDEX 
 
 431 
 
 Single Bail 
 
 Single rail A. C. track circuits, 114- 
 119 (see also track circuit 
 A. C.). 
 
 Solenoid dwarf signals: 
 Model 2: 
 
 Circuits for, 84, 260, 261. 
 Control of, 83, 84. 
 Control wires for, 83, 308. 
 Description of, 83-85. 
 Dimensions of, 246, 247. 
 Foundations for, 253. 
 Illustration of, 83. 
 Length of control wires for, 
 
 308. 
 
 Names of parts for, 85. 
 Operating data for, 241. 
 Operating mechanism for, 85. 
 Size of control wires for, 308. 
 Weights of, 366. 
 Model 3: 
 
 Circuits for, 84, 262. 
 Control of, 83, 84. 
 Control wire for, 83, 308. 
 Description of, 86, 87. 
 Dimensions of, 247. 
 Foundation for, 253. 
 Illustration of, 86. 
 Length of control wires for, 
 
 308. 
 
 Names of parts for, 87. 
 Operating data for, 241. 
 Operating mechanism for, 87. 
 Size of control wire for, 308. 
 Weights of, 366. 
 Soldering : 
 
 Fluxes for, 299. 
 Wire joints, 298, 303. 
 Specific gravity of: 
 Brick, etc., 386. 
 Cement, etc., 386. 
 Comparison with Baume's Hy- 
 drometer, 384. 
 Electrolyte, 146. 
 Liquids, 385. 
 Metals, 387. 
 Sand, etc., 386. 
 Stone, etc., 386. 
 Wood, 385. 
 Specifications (see under name of 
 
 material) . 
 Spectacles : 
 
 Blades for, 249. 
 Clamp bearing for, 79. 
 Dimensions of, 248. 
 Dwarf bearings for, 79. 
 Torque curves for, 250. 
 Square measure, table of, 388. 
 
 Switch 
 
 Stakes: 
 
 Specifications for, 312, 313. 
 Weights of, 367. 
 Stations, interlocking, 31-35 (see 
 
 also interlocking station) . 
 Stick locking, 137 (see also electric 
 
 locking) . 
 Stone: 
 
 Concrete, size for, 325. 
 Measuring box for, 323. 
 Quantities for concrete, 324. 
 Sizes for concrete, 325. 
 Specific gravity of, 386. 
 Weights of, 386. 
 Storage batteries (see batteries, 
 
 secondary) . 
 Switches: 
 
 Battery charging, description and 
 
 circuits, 160, 161. 
 Nomenclature of, 336. 
 Panels for (see panels). 
 Symbols for, 357, 358. 
 Switchboards: 
 Operating : 
 
 Cross protection circuit breaker 
 
 for, 90-92. 
 
 Description of, 45, 46. 
 Dimensions of, 181. 
 Illustrations of, 43, 44. 
 Lighting panels for, 182. 
 Location of, 37. 
 Polarized relay for, 92, 93. 
 Simplified circuits for, 45. 
 Weights of, 363. 
 Wiring for, 181. 
 Power : 
 
 Description of, 40-45. 
 Dimensions of, 176-180. 
 Illustrations of, 41-43. 
 Location of, 37. 
 Lighting panels for, 182. 
 Manipulation of, 176-180. 
 Simplified circuits for, 43. 
 Starting panels'for, 181. 
 Weights of, 363. 
 Wirings for, 176-180. 
 Switch boxes (see switch circuit con- 
 trollers). 
 Switch circuit controllers : 
 
 Connections to switch pointfor,232. 
 Model 3, Form D: 
 Dimensions of, 230. 
 Illustrations of, 97. 
 Weights of, 366. 
 Model 4: 
 
 Description of, 69. 
 Illustrations of, 69. 
 
432 
 
 INDEX 
 
 Switch 
 
 Switch circuit controllers: (Con.) 
 Model 5, Form A: 
 
 Adjustable cam for, 231. 
 
 Cam for, 231. 
 
 Description of, 98. 
 
 Dimensions of, 231. 
 
 Illustrations of, 98, 99. 
 
 Weights of, 366. 
 Symbols for, 357. 
 Weights of, 366. 
 Switch layouts: 
 
 Model 2 switch machine: 
 
 Double slip switch, 223. 
 
 Hayes derail, 220. 
 
 Movable point frog, 224. 
 
 Movable point frog with double 
 slip switch, 225. 
 
 Single slip switch, 222. 
 
 Single switch, 218. 
 
 Slip switches, 222, 223. 
 
 Split point derail, 219. 
 
 Weights of, 364, 365. 
 
 Wharton or Morden derail, 221. 
 Model 4 switch machine: 
 
 Double slip switch, 223. 
 
 Hayes derail, 220. 
 
 Movable point frog, 224. 
 
 Movable point frog with double 
 slip switch, 225. 
 
 Single slip switch, 222. 
 
 Single switch, 218. 
 
 Slip switches 222, 223. 
 
 Split point derail, 219. 
 
 Weights of, 364, 365. 
 
 Wharton or Morden derail, 221. 
 Switch machine: 
 Model 2: 
 
 Adjustment of, 201-204. 
 
 Advantages of dynamic indica- 
 tion of, 24. 
 
 Circuits for, 20, 61, 226, 228. 
 
 Clearance compared with Model 
 4 switch machine, 214. 
 
 Control of, 60. 
 
 Control wire for, 19, 60, 308. 
 
 Cross protection for, 24-26. 
 
 Cycle of movements of, 212. 
 
 Description of, 64-67. 
 
 Description of circuits for, 
 19-22. 
 
 Dimensions of, 216. 
 
 Double lever for, wiring of, 228. 
 
 Drilling of lock rod for, 205. 
 
 Dynamic indication for, 21, 24, 
 60, 67. 
 
 Energy data for, 214. 
 
 Illustrations of, 21, 62, 63. 
 
 Switch 
 
 Switch machine:' (Con.) 
 Model 2: 
 
 Indication selector for, 58. 
 
 Installation data for, 199-206. 
 
 Layouts for, 218-225. 
 
 Length of control wire for, 308. 
 
 Lever, illustrations of, 51, 56. 
 
 Lever, operation of, 49, 50. 
 
 Maintenance of, 199-206. 
 
 Motor connections of, 201. 
 
 Names of parts for, 65, 200. 
 
 Operating data for, 214. 
 
 Operation of, 60-67. 
 
 Operation of controlling lever 
 for, 49-50. 
 
 Pole changer for, 64. 
 
 Pole changer movement for, 
 202. 
 
 Pole changer wiring for, 203. 
 
 Safeguards of, 61-63. 
 
 Simplified circuit for, 20. 
 
 Size of control wire for, 308. 
 
 Spring attachment for, 63. 
 
 Storing of, 199. 
 
 Switch circuit controllers for 
 (see switch circuit control- 
 lers). 
 
 Testing of, 204, 205. 
 
 Tie framing for, 19Q. 
 
 Time of operation of, 22, 214. 
 
 Tools for maintenance of, 369, 
 370. 
 
 Typical circuits for, 20, 61, 226, 
 228. 
 
 Weights of, 365. 
 Model 4. 
 
 Adjustment of, 209, 210. 
 
 Advantages of dynamic indica- 
 tion of, 24. 
 
 Circuits for, 20, 61, 227, 228. 
 
 Clearance between third rail 
 and, 215. 
 
 Clearance compared with Model 
 2 switch machine, 214. 
 
 Control of, 60. 
 
 Control wire for, 19, 60, 308. 
 
 Cross protection for, 24-26. 
 
 Cycle of movements of, 213. 
 
 Description of, 67-69. 
 
 Description of circuits for, 
 19-22. 
 
 Dimensions of, 217. 
 
 Double lever for, wiring of, 228. 
 
 Dynamic indication for, 21, 24, 
 60. 
 
 Energy data for, 214. 
 
 Illustrations of, 16, 19, 67. 
 
INDEX 
 
 433 
 
 Switch 
 
 Switch machine: (Con.) 
 Model 4: 
 
 Indication selector for, 58. 
 
 Installation data for, 207-211. 
 
 Layouts for, 218-225. 
 
 Length of control wire for, 308. 
 
 Lever, illustrations of, 51, 56. 
 
 Lever, operation of, 49, 50. 
 
 Maintenance of, 211. 
 
 Motor connections of, 209. 
 
 Names of parts for, 66, 208. 
 
 Operating data for, 214. 
 
 Operation of, 67-69. 
 
 Operation of controlling lever 
 for, 49, 50. 
 
 Pole changer for, 68. 
 
 Pole changer wiring for, 210. 
 
 Safeguards of, 61-63. 
 
 Simplified circuit for, 20. 
 
 Size of control wire for, 308. 
 
 Storing of, 207. 
 
 Switch circuit controllers for, 69. 
 
 Testing of, 210, 211. 
 
 Third rail clearance for, 215. 
 
 Tie framing for, 207. 
 
 Time for operation of, 214. 
 
 Tools for maintenance of, 369, 
 370. 
 
 Typical circuits for, 20, 01, 
 227, 228. 
 
 Weights of, 365. 
 Symbols for, 350. 
 
 Switch mechanisms (see switch ma- 
 chine). 
 Switch operating mechanisms (see 
 
 switch machine) . 
 Symbols : 
 
 Lever contacts, Model 2 inter- 
 locking machine 336. 
 R. S. A. standard: 
 
 Charging apparatus, 359. 
 
 Circuit controllers, 356-358. 
 
 Circuit plans, 354-359. 
 
 Instruments, 357-359. 
 
 Location, 350-353. 
 
 Relays, indicators and locks, 
 354, 355. 
 
 Signals, 348, 349. 
 
 Switches, derails, etc., 352,353. 
 
 Track plans, 348-353. 
 
 Tables (see under name of material) . 
 Tanks: 
 
 Cooling, for gasoline engine: 
 Capacity of, 174. 
 
 Track 
 
 Tanks: (Con.) 
 
 Cooling for gasoline engine: 
 Dimensions of, 174. 
 Location of, 171. 
 Specifications, R. S. A., for, 174, 
 
 175. 
 
 Water connections for, 170. 
 Gasoline : 
 
 Capacity of, 174. 
 Dimensions of, 174. 
 Location of, 171. 
 Specifications, R. S. A., for, 
 
 174-175. 
 
 Taylor (G. R. S.) electric interlock- 
 ing system (reprint), 405- 
 413. 
 Temperature : 
 
 Comparison of Fahrenheit and 
 
 Centigrade scales, 392, 393. 
 
 Effect on G. R. S. electric plants, 
 
 10, 11. 
 Effect on mechanical plants, 10, 
 
 11. 
 Terminal boards: 
 
 Interlocking machine, 57. 
 Transformer, 122, 123. 
 Tests (see under name of apparatus) . 
 Thermometer scales: 
 
 Comparison of Fahrenheit and 
 
 Centigrade, 392, 393. 
 Threads, U. S. standard screw, 
 
 380. 
 Tie framing: 
 
 Model 2 switch machine, 199. 
 Model 4 switch machine, 207. 
 Time release: 
 
 Electrical, 133, 134. 
 Mechanical, 58, 59. 
 Symbols for, 358. 
 Tools, maintenance, 369-370. 
 Towers (see interlocking stations). 
 Track circuits: 
 
 Alternating current, double rail: 
 Bonds for, 120, 121. 
 Diagram of, 273. 
 Energy curves for, 273. 
 Impedance bonds for, 120, 121 
 Relays for (see relays A. C.). 
 Transformers for (see trans- 
 formers) . 
 
 Alternating current, single rail: 
 Advantages of, 114. 
 Central energy scheme, 117- 
 
 119. 
 
 Description of, 114-119. 
 Diagrams of, 116, 117. 
 Energy required for, 115. 
 
434 
 
 INDEX 
 
 Track 
 
 Track circuits : (Con.) 
 
 Alternating current, single rail: 
 Illustration of, 118. 
 Limitations of, 114, 115. 
 Relays for (see relays A. C.). 
 Transformers for (see trans- 
 formers) . 
 
 Types of, 116, 117. 
 Direct current: 
 
 Batteries for (see battery, 
 
 primary) . 
 
 Bond wires for, 378. 
 Boot leg for, 316. 
 Channel pins for, 378. 
 Indicators for, 103-106 (see also 
 
 indicators) . 
 Locking circuits for (see electric 
 
 and check locking). 
 Relays for (see relays, D. C.). 
 Tests for, relays, 276. 
 Tools for, 370. 
 Wire sizes for, 297. 
 Track diagrams, 102-106. 
 Track indicators: 
 Alternating current: 
 
 Description of, 111-113. 
 Dimensions of, 270. 
 Energy data for, 271. 
 Weights of, 366, 367. 
 Direct current: 
 
 Description of, 103-105. 
 Dimensions of, 268. 
 Energy data for, 265, 269. 
 Illustrations of. 103-105. 
 Weights of, 366. 
 Track plans: 
 
 Dog chart for, 55. 
 Illustrations of, 54. 
 Locking sheet for, 54. 
 Symbols for, 348-353. 
 Track tools, list of, 370. 
 Track transformers (see trans- 
 formers) . 
 Transformers : 
 
 High tension line: 
 
 Capacity of, 280, 281. 
 Combinations of, 122, 123. 
 Description of, 122, 123. 
 Dimensions of, 279. 
 Hanger irons for, 279. 
 Illustrations of, 122. 
 Ratings of, 280, 281. 
 Terminal board for, 122. 
 Weights of, 363. 
 Windings for, 122, 123. 
 
 Weight 
 
 Transformers: (Con.) 
 Secondary track: 
 
 Description of, 123, 124. 
 
 Dimensions of, 282. 
 
 Illustration of, 123. 
 
 Rating of, 282. 
 
 Weight of, 363 
 
 Windings for, 123. 
 Symbols for, 359. 
 Trunking: 
 
 Area of groove in, 314. 
 
 Board feet for, 315. 
 
 Bootleg for, 316. 
 
 Capacity of, 314. 
 
 Capping for, 315. 
 
 Construction of, 312, 316. 
 
 Dimensions of, 315. 
 
 Hooks required for, 317. 
 
 Joints in, 312, 315. 
 
 Junction box for, 313, 316. 
 
 Nails required for, 317. 
 
 Paint required for, 374. 
 
 Screws required for, 317. 
 
 Sections of, 315. 
 
 Specifications for, 312, 313. 
 
 Stakes for, 312, 313. 
 
 Supports for, 312, 313. 
 
 Surfacing of, 315. 
 
 Table for determining size of, 314. 
 
 Weights of, 367. 
 
 W 
 
 Weight: 
 
 Avoirdupois, 388. 
 Brick, etc., 386. 
 Cement, etc., 386. 
 Electrolyte, 146. 
 Lag screws, 382. 
 Metals, 387. 
 Nails, 382. 
 Pipe, 381. 
 Sand, etc., 384. 
 Shipping : 
 
 Battery chutes, 367. 
 
 Bracket posts, 365. 
 
 Cantilever bracket, 366. 
 
 Charging apparatus, 363. 
 
 Detector bar layouts, 365. 
 
 Dummy mast, 366. 
 
 Dwarf signals, 366. 
 
 Fixed arm, 366. 
 
 Generators, 363. 
 
 Impedance bonds, 367. 
 
 Indicating relays, 366. 
 
 Indicator groups, 366. 
 
 Indicators, 366, 367. 
 
INDEX 
 
 435 
 
 Weight 
 
 Weight: (Con.) 
 Shipping : 
 
 Interlocking machines, 363, 
 364. 
 
 Junction boxes, 367. 
 
 Lever lock, 364. 
 
 Lighting panels, 363. 
 
 Locking, 364. 
 
 Motor generators, 363. 
 
 Posts for relay boxes, 367 
 
 Relay boxes, 367. 
 
 Relays, 366. 
 
 Signals, complete, 365, 366. 
 
 Signals, dwarf, 366. 
 
 Signals mechanism, Model 2A, 
 366. 
 
 Stakes, 367. 
 
 Switchboards, 363. 
 
 Switch circuit controllers, 366. 
 
 Switch circuit controller rods, 
 366. 
 
 Switch layouts, 364, 365. 
 
 Switch machines, 365. 
 
 Transformers, 363. 
 
 Trunking, 367. 
 Stone, etc., 386. 
 Storage battery cells, 146. 
 Tables of, 388, 389. 
 Water, 389. 
 Wire, 306, 307. 
 Wood, 385. 
 
 Welding, fluxes for, 299. 
 Wire: 
 
 Aluminum compared with copper, 
 
 310. 
 Common return, 19, 22, 60, 70, 83, 
 
 93, 309. 
 
 Control for signals, 22, 70, 83, 308. 
 Control for switches, 19, 60, 308. 
 Copper (see also rubber-covered) : 
 
 Carrying capacity of, 310. 
 
 Compared with aluminum, 310. 
 
 Fluxes for soldering, 299. 
 
 Gauge for, 305. 
 
 Hard drawn, table of, 307. 
 
 Interlocking specifications, R. 
 S. A., 297-299. 
 
 Joints in, 298-304. 
 
 Soft drawn, table of, 306. 
 
 Soldering of, 303. 
 
 Splicing of, 298-304. 
 
 Taping of, 303, 304. 
 
 Zinc 
 
 Wire: (Con.) 
 
 Copper-clad, table of, 307. 
 Gauges for, 305. 
 Individual return, 94. 
 Iron, table of, 306. 
 Rubber-covered copper: 
 Conduit for, size of, 314. 
 Interlocking specifications, R. 
 
 S. A., 297-299. 
 Joints, 298-304. 
 Manufacturer's Engineers' 
 
 standard, dimensions of, 311. 
 R. S. A. standard, dimensions 
 
 of, 311. 
 
 Soldering of, 304. 
 Splicing of, 298-304. 
 Tags for, 299. 
 Taping of, 303, 304. 
 Trunking for, size of, 314. 
 Steel, table of, 306. 
 Symbols for, 359. 
 Weights of, 306, 307. 
 Wirings (see circuits, also name of 
 
 apparatus) . 
 Wood, specific gravity and weight 
 
 of, 385. 
 Written circuits: 
 
 Description of, 331, 332. 
 Nomenclature of: 
 Circuits, 334-336. 
 Circuit controllers, 334-336. 
 Indicator contacts, 335. 
 Knife switch, 336. 
 Latch contact, 336. 
 Lever contacts, numbering of 
 
 336. 
 
 Operated units, 332-334. 
 Push button, 336. 
 Relay contacts; 335. 
 Terminals, 336. 
 Time release contacts, 335. 
 Wires, 337, 338. 
 Illustrations of, 338, 339. 
 Plans involved, 331, 332. 
 Use of, 331. 
 Wrought iron pipe: 
 Dimensions of, 381. 
 Weight of, 381. 
 
 Zinc for gravity battery cell, 290. 
 
14 DAY USE 
 
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 Renewed books are subject to immediate recall^ 
 
 __i^OiJS91 
 
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 REC'b uWN 1 3 1995 
 
 FEB 
 
 
 
 LD 21A-50m.l2,'60 
 
 General library . 
 University of California 
 Berkeley