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Un des symboles suivants apparaftra sur la darniAre image de cheque microfiche, selon la cas: la symbole — ► signifie "A SUIVRE". le symbols V signifie "FIN". Maps, plates, charts, etc., may Im filmed at different reduction ratios. Those too lerge to be entirely included in one exposure ara filmed beginning in the upper left hand corner, left to right and top to bottom, aa many framea aa required. The following diegrams iiluatrata the method: Les cartes, planches, tableaux, etc., peuvent Atre fiimto A des taux da reduction diff Arants. Loraqua le document eat trop grand pour Atre reprodult en un seul clichA, 11 est film* A partir da I'angie supArieur gauche, de gauche A droits, et de haut an baa, an pranant le nombre d'imagea nAcaaaaira. Lea diagrarnmes suivants lllustrent le mithode. rrata to pelure, nA 3 32X 1 2 3 1 2 3 4 5 6 RAILWAY ENGINEERING BY CECIL B. SMITH. Ma.E.. l.ate Assistant Professor of Civil I'2ngineering in MoGill University. Member Canadian Society of Civil Engineers. FIRST EDITION. TOrvONTO AND MONTREAL: Canadmn Enoineer— Biggar, Samuel & Co. iSqg TFI45, S^ V Vv * A. u-^J-ej^ Tfv This Hook is respectfully dedicated to Sir William C. VanHoknk. President of the Canadian Pacific Railway Company, who has so successfully directed its policy as to make it a great National and Imperial Highway, a blessing to the country, and a finan- cial success. 1^ ta^.'^'ll rv^ CONTENTS. PARTI. t MA I' IKK F— FUNDAMKNTAI. ( "oNSI 1 )|;|< Al IONS. Tmnsiiortation in (leiu-ral Progress of Railway Transportation-nis- tinclivo features (.f our railways -railway projecls-lvssentials t„ success of-Mases of projects-'lramc-(irowth of A'olume of-lYunk and brand. lines-Receipts— Railway statistics for Canada, I'.S.A. and (Jreat Britain fur 1895— Analyses of workings of Canaclian systems— 'lahles of. ClIAITKK II— 'iKArN KKSISTANCI.S AND TlIl.tK ( < )ST. \-arious resistances- Level tanjjent-Axles- fournals- Formula- for- (.rade resistances-Curve resistances-'Ihoorv of amount of-Fllevation of outer rail on curves-Cost of curve resistances- Cost of grade resist- ances- Net train loads-Cost of ruling gradient- Comparison of routes for operation and investment. ClIAI'TKK III— CUKVI'.S. X'ertical curves- Necessity for -Amount and where to be placed-Method of use-Circular curves-Method of placing on ground-of keeping notes -Formula for placing stakes by offsets-Trans'tion curves-Theory of -Value of-Various kin.ls- Spirals-C:nbic parabola-Theory of-Form- ula; for placing by oftset- J)itt<, for running in bv detiection-Special problems— Reclining track. CriAI'TKK I\'— SlJKVKVS. Classification-Reconnaisance-Fundamentals of— Instruments to use- Trial lines-Instruments to use-^ .Make-up and personal (|ualities of mem- bers of party-Duties-Approximate estimates- Location surveys-Added duties-Ioiwgraphy-Iiench marks -Offsets- Information to be obtained. ClIAI'TKK \'— RoADKK.I) CON.STKUCTION. Waterways-Study for areas rcquired-F'ormu'£«-Plank boxes and cul- vert pipes— Discussion-Designs for headwall and trench— Table of cost- Open culverts- Designs for stone and lii.iber-Discussion- -Table of cost —Box culverts- Designs for stone and wood— Discussion and descriptipn of headwalls etc.— Specification for stone box culverts— Table of cost- Arch culverts- Designs for- Use of concrete— Distinctive features of designs-Timber centres- Arch sheeting-Specification for stone culvert masonry-Larger arch designs-Firidges-Abutments-Designs-Approxi- mate quantities and diagrams of Wing-"U" " T"-Tower and com- bination abutments-Stone iiiers— Designs-Distinctive features-Specifi- cation for first class bridge masonry— Metal pier designs— Iron viaducts- General outline and layout- lormula for weight of metal— Pedestal CONTKNTS. masonry— TimfwrlVestles— Foundations— Mvi(l>.ills—I'",n(l bents— ncsij'iis of systinns— Hif;h trestles -Uraciny — Floor systems— Dt^signs for— Illfva- tion of rtoor on curves — Approximate (juantity of Timber in trestles — I'oundatioiis — Designs and discussion — Land I'oundations— I'iles and pile- driving— I'ormuIfK for safe loads — I'oimdations in water — CJoHerdams — l'"loating and bottomless caissons— Compressed air — ( 'ost of— C)|)en dredg- ing — Designs for— Laying out and measuring work Oross-sections - FormuliK for areas and (|uant'tie:; — I'-ckel's and Prismoidal formulu!— Classification of material — S|)ecification for excavation— Surface tlrain- age— ("atch-water, cut and slope ditching, Chaptkr VI— Railway Law. General discussion of — Powers of railway committee — Privileges and powers of a railway company — Powers with limitations, and special duties of a company — With reference to survey, construction and maintenance — General duties of a railway to the country and to individuals. PART n. Chaptkr I— 'iKArK. Drainage— P'orms of roadbeds — Ditches — Shrinkage of banks — Uses and kinds of ballast — Surfacing — Wooden ties— Objections to use of— (Quali- ties and kinds of — Tie preservatives — Metal ties — Varieties of — Post and Hartford metal ties— Rails— Bullhead rails — Flanged rails— Shapes of rail sections — Rail wear — Chemical composition — Physical drop tests — Rail joints —Spikes — Tie plates— Wood screws and fang bolts — Turnouts — Systems of — Frogs— Stiff and spring frogs — Switch calculations — Middle F'rog calculations. ADDENDA. Statistics of Canadian Railways, 1897. Diagrams of approximate quantities in various classes of structures. LIST OF PLATES, DIAGRAMS, ETC '■'«• I Diagram lllustratin« (mikIi- Resistance 38 ^ " " L'se of \elocity Hoad 31 l"''K'*. 3-7 W:iKrams llliiMiatiny Cuive Hesistaiues, etc ., 34 ^'^^ " " L'se and Calculations of Vertical < '"'■^■fs ^^ ** 13 l>ii>Knini for Staking (.irciilar Curves l)y()ffsets ' 45 14- '8 Diagrams for Transition Curves . , '9 " " <'arrying Straight Lines Past Obstacles. 73 I'lalc 1 I'lank Boxes, I'ipe Ueailwalls and Irenclies 79 II limber and Stone Open Culverts g^ "I I'ile Culvert and Three Span Opening g- IV Timber and Stone Hex I'ulverts g? ^' Stone Hox Culvert go ^'I Stone and Drystone Uox Culverts go " ^'11 Stone Arch t'ulverts VIII Stone Arch Culvert „. • . l/^f " IX Stone or Brick Arches „(, X Arch Centres, Headwalls, Sheeting („ XI Wing Abutments " XII " T " Abutment ,qj XIII " U " Abutment and Abutment Types ,06 Diagram for Approximate (,)uantities of Bridge Abutments 109 Xl\' Masonry— Bridge Piers ^^^ XV Metal and Metal and Concrete Bridge Piers ,,5 X\'l Iron and Timber Trestles— Trestle Foundations .19 X\'ll Timber Trestle Framing, Latimer Cniard ,22 X\I 1 1 Timber Trestle Floors j^^ Illustration of Concrete and Pile Foundation 130 " XIX Sections of Cofferdams , , " XX Pneumatic Caissons, Open Dredging , .g " XXI Diagrams for ICarthwork Staking and C^Hiantities 142 XXII Sections of Road-beds, Ballasting etc ,5- " XXIII Rail Sections ['/[ ,^^ XXIV Rail Sections lyl XXV Steel Ties, Rail Fastenings, Wheel Treads etc. ,77 " XXVI Rail Joints ' ' ' ' /g[ XXVII Outlines of Turnout Systems j^. " XXVIII Switches and Frogs jg Diagram ol Feet B.M. in Timber Trestles 192 Open Pile Culverts 193 Beam Culverts 194 of Cubic Yds. in Open Stone Culverts 195 " " Stone Box Culverts 196 of feet, B.M. in 'Timber Box Culverts 197 LIST OF TABLES. Tah .; I II III IV V VI \'ll VIII IX X XI XII XIII XIV XV XVI I In HAOI Inci'-aso of Populiition nnd Railway I'.arniiiK's, I'.S.A and Canada ,o Railway Statistics 1895, Canada, (Jicat Uritain and I'.SA. 14 Analysis of ( anadian Railway Statistics, iHqj, 20-31 l-cvfl TanKi-nt Resistances to Train-Hnuling 37 W'locity I loads for N'arioiis .Speeds 39 Super-I'.levaliun of Outer Rail on ( urves 3a Wheel Sli|)|)a(,'e for X'arious Curves ^e Net Train Loads for Various I'-ngines and (Jrades 38 Kffect of iMifjine Mileage on 0|R'rating l''-.\penses 40 Itemized Cost per Mile, New York Central R. R 42 Approximate Cost of Sewer and C. 1. I'ii)es 80 " Open Culverts 83 " " " Box Culverts gi t^uantities of Masonry in Abutments ,38 rimher in Trestles 138 Railway Statistics for Canada for 1897 191 RAILWAY ENGINEERING. lNTROr)UCTION. This book is the outcome of an endeavor on the writer's part to epitomize a vast subject into such a compass that the student or layman whose experience is pre-supposed to be *• nil " may grasp it in an intelli- gent way. It is intended to be a foundation course only, and as such, has been largely selected from the various works bearing on each department of the sub- ject ; but the proper balancing of the parts, if such there be, giving each its due importance, the combina- tion of the whole subject, technically considered, as a ground work for future study, and the exclusion of much confusing detail which obscures the mental vision, the writer may claim as his own. During the present period of depression, which al- ways so seriously affects railway construction, it might be thought that the vocation of the railway engineer was being largely obliterated ; but this is not at all a consequence. Our railways must be maintained, and while more engineers, per mile, are employed during construction than afterwards on maintenance, yet, although there are, no doubt, pleasant and remuner- ative positions to be had during the former ^eriod, there is no condition of permanence that makes them desirable. On the other hand, railway companies recognize more, every day, the value of a technical engineering training for those young men who fill junior positions i" the operating and maintenance departments, not sti ctly engineering in their nature. And those companies {e.g., Pennsylvania, or Nor- folk and Western) that have persistently filled such positions with young engineering graduates, that have had them do routine work and given them a business training, have seen their highest offices filled by men whose engineering knowledge has brought them to the front, when aided by a good business training, a know- ledge of ways and means, and of traffic and operation. In the future, such positions, and those on the main- tenance staff proper, woald seem to be the paths more likely to lead to success than the more strictly technical Railway Engineering. work of location and construction, particularly as the construction in future will be chiefly in the shape of short extensions of large systems having permanent staffs. This book, however, will deal chiefly with location, construction and maintenance, not because these cover the whole ground, but because a knowledge of traffic, rates, operation and management can be gained only by experience, whereas a good grasp of the former may be had previous to employment of such an extent, at least, as will be valuable in obtaining and filling junior raihvay positions, and also form a basis for future study. And even though very little of what is here given may be used at once by the young engineer, yet it will enable him to take a more intelligent interest in all that his superior officer does, which he could not otherwise do unless he had a proper understanding of the general principles on whicV railways are surveyed, constructed and operated. He IS warned against having his faith in these priiiciples shaken by the adverse criticism of men who do not ap- preciate or understand them. Care is taken to give here only what is fairly well tried and established. On the other hand, he is advised to keep his opinions, largely, to himself, and to carry out faithfully the instructions of his superiors in office. These in- structions, though perhaps sometimes faulty, should be studied and respected, so that when the time arrives that he, in turn, gives orders which must be obeyed, he may put into practice what he then considers, after several years' experience, to be best, not only theoreti- cally, but from the standpoint of beinr feasible and advantageous, capable of being put into execution by his assistants — the best, all things considered. It must not be forgotten that this work is not exhaustive, but merely introductory. Years ji reading, conversation, experience, observation, and above all, honest hard thinking, are necessary to complete a man's knowledge on any subject, and even then it is not com- plete. So that we must never desist, but always per- severe, if we wish to keep up with the progress of this most progressive subject. C. B. S. Montreal, Que., Canada, May, 1897. Railway Engineering. CHAPTER I. Fundamental Considerations. ARTICLE I. TRANSPORTATION. The inhabitants of the civilized world have, since the year 1825, been enabled to remodel their ideas of how and where to live. There has been developed within this period a new potentiality, which had through all the previous history of the world been practically dor- mant. The impulse -iven by it to the material and industrial progress of the world is such as to stamp it as one of the grandest events of our world's history, and It will be so spoken of in future ages. It is the develop- ment of transportation. In its broadest sense, transportation may be said to include all means of communication ; but of its various phases the transportation of material objects by means of the railway train will be the one treated of in this book. The railway had its birth in England, and a fierce struggle took place between it and the canal for supre- macy, while in North America the canal systems not being far advanced, and the extent of territory to be traversed rugged and vast, the result was never in doubt ; to-day, the canal is a useful regulator of rates, and a means of transportation of heavy bulk freights in which time is not a factor, but it cannot be said to be a competitor of the railway to any serious extent. By 1850 the people of North America had grasped the fact that the rapid extension of our railways to the remote and unsettled regions westward, was the key to that marvellous gro vth that has peopled a continent in so short a time. The capital available was small and the country fairly rough, so that different methods Railway Engineering. of construction and operation from those in vogue in England, and a consequent different class of equipment, were imperative. At the present day, in Canada, our railways are de- veloped along the same general lines as those of the United States, and m it we have done our fair share, but it must be recognized that to the civil engineers of the United States is due the credit of those essential de- partures from early forms which have defined our con- tinental types so distinctly, and are the glory and the boast of North Americans. These departures took place gradually, the gap becoming wider every year, until now it has passed its maximum, and the slow conservatism of English engineers is yielding. Bogie trucks, equal- izing levers, VVestinghouse brakes, and American cars are becoming familiar in England, while on the other hand increased wealth and traffic are enabling American railways to introduce block-signalling and interlocking systems, to abolish many grade crossings, and make their road-beds more solid and permanent. The distinctive features of the railway system of North America that have enabled it to extend to a length of over 200,000 miles (including Mexico and Central America), that have given Canada a system of over 16,000 miles, moving 22,000,000 tons of freight, 14,000,- 000 passengers, 60,000,000 newspapers, 100,000,000 letters, besides much express, etc., each year, having a capitalization of $900,000,000, and employing an army of perhaps 55,000 men, are as follows: (i) A frank recognition of the fact that curvature is not a great drawback, and can be introduced freely to economize construction. (2) The introduction of bogie and swivelling trucks and equalizing levers, enabling lines of poor surface and sharp curvature to be operated safely and economi- cally. (3) The use of long wheel-bases on engines for freight work, enabling greater weight to be put on the drivers of engines operating over quite inferior track. (4) The consequent hauling of increasingly heavier loads of freight per engine and per train crew. Railway Engineering. 5 (5) The lowering of freight rates to a point that enabled coarse freights to be worth moving, thereby increasing the volume of freight enormously. (6) The acceptance of a timber-construction period, enabling roads with meagre early traffic to pay their small fixed charges and survive until their finances and credit are such as to enable them from their earnings or by increased bonding to replace such structures with permanent ones. The Canadian Pacific Railway is a striking example of this. (7) The use of increasingly heavier freight cars, in which paying freight is a larger percentage of the gross load — and also giving a less co-efficient of rolling friction — which the following table illustrates : 1875.. ..20,ooo lbs. car, 20,000 lbs. freight, 50 per cent, dead load 1880.. ..24,000 " 40,000 " 37 " " iSgo.. ..28,000 " 60,000 " 31 " " 1896 36,000 " 80.000 " 31 From which it appears that the limit has been reached. ARTICLE 2. — PROJECTS. A company of limited liability, but whose capital is inelastic and non-circulating, must do business or break down; it cannot contract its business in hard times except at a sacrifice ; business at starvation wages is better than none, and this is the exact condition of a railway company which is a manufacturer and seller of transportation. In this it is diflferent from a store, or more particularly a banking house, therefore all the more carefully should the project be studied before money is embarked in it. No considerations of a general character will cover all cases, and therefore it will be necessary to exclude roads which have been or may be built (a) for purposes of blackmail, to force, rival companies to buy them out ; (6) for speculation of the builders, not owners. These are not legitimate enterprises, but ones which projectors start by the expenditure of a small sum for charter, issuo of bonds, etc., expecting to charge a margin for selling the bonds, to form consti action companies, and let the contracts of construction to themselves at high prices, getting all the money out of the bondholders, Railway Enginreking. running no risk themselves, but controlling all manage- ment by means of valueless stock. This gives them all the voting power, and any extra profit remaining after the bond coupons have been paid. Even such roads as these, however, will profit in the same way, as legitimate enterprises, by the application of true economy in .:)ca- tion and construction. Cost is the basis of all business, and most particu- larly in the case of railways must this always be so. An engineer may insist on technical accuracy and mas- sive work, to such an extent as to bankrupt his com- pany before the road is on a paying basis or even built, or he may, in an ill-directed effort toward economy, give it such a mist^rable constitution of grades and position, relatively, to its customers, that it will never secure traffic, and could not handle it economically if it did. Between these two extremes, the intelligent engi- neer should strike a happy balance, so that the project may be where it can obtain most traffic, at least first cost consistent with moderate working expenses, so that it will be profitable to the present owners oi pro- moters, who usually buid the road on borrowed money up to a certain safe mortgagable amount. The promoters of roads are always sanguine, and probably the most common error mto which such men usually fall, is to overrate the funds on hand or in view, and on the other hand, to underrate the cost of the completed enterprise. Roads are seldom built within their first estimated cost, and therefore, this is a danger against which the chief engineer must. guard ; he must be sure and firm in his figures, because it is difficult to foresee all contingencies, and still more so to impress the directors with the reality or necessity of each item. The finances at the command of the company should always be fully known to the chief engineer ; he has the right to know it, and should have the courage to insist on the fullest confidence of the directors. These means should be carefully studied, allowances made for changes in the money market affecting the value of bonds, the amount of money which can be raised easily, and the difficulty in getting the last part Railway Enginrkring. of the required amount should also be considered. Usually the bonds of new roads, just being built, sell below par, and, as the amount issued increases, the selling price may get h^ss and less, until they may become unsaleable. ' Many roads become bankrupt before or just after construction is finished, and a promising project ends in a receivership, thi. wiping out of past debts, or issue of prior-lien bonds on the part of the bondholders them- selves. Receiverships, instituted originally to protect bondholders, are often made the instruments of defraud- ing them. The history of the railways of the United Stares, particularly, is full of examples of unnecessary roads built on faith and hope, and ending in disaster or fraud. Over 25 per cent, of United States railways are now in receivers' hands, and nearly all have passed through that stage in some period of their history. The most casual observation teaches that in a coun- try like Canada, where traffic is still unfortunately very light, we must build roads with the utmot>c economy. This has been practised in several justifiable directions. (a) The introduction of curves where necessary, with a sharpness of as high as 4"^ to 6*^ on main lines, and 8*' to 10'' on branches, with a frequency only limited by a piece of tangent of 200 to 400 feet long between curves ; in this way, by a slight addition to the cost of hauling trains and length of line, the cost of road-beds has been kept at a minimum. {b) The use of fluctuating grades, by which the local " sags " or depressions do not increase the cost of hauling trains, but cheapen the cost of construction materially, and which have no objectionable feature except a change in train speed's, as they store up or yield a part of their " velocity head." (c) Timber structures over all important streams, and even timber box culverts under light banks ; in this way a railway company is enabled to get its road in operation quickly at a minimum cost, is able often to tide over the first few years of meagre traffic, replac- ing them, gradually, as means will permit, with per- 8 Railway Engineering. manent structures. On the other hand, there are certain directions in which economy cannot be practiced. (a) Narrow gauge roads, except in isolated cases, have now been abandoned, because the demands for interchange of traffic put them at a disadvantage ; be- cause the cost of construction is higher in proportion to carrying capacity of cars, etc., and .:hiefly because it is found that American engines of tandard gauge can pass around any ordinary curve quiie freely. (6) Light rails. This will be dealt with more fully in future chapters, but it may be well t ) say here that with rails quoted at $20 to $25 pet ton, there is no greater blunder than to buy light rails. In stiffness, strength and wear the increase varies nearly as the square of the weight per yard, thereby decreasing maintenance charges enormously as the weight in- creases. The present weights are roughly 60 lbs. per yard for branches and 80 lbs. for our main lines, with a strong tendency upwards. (c) Excessive ruling gradients. Almost any other mistake can be corrected in time, curves can be flat- tened, short grades lifted, temporary structures replaced, but the ruling grade is the life or death of a road that has or expects to have any traffic beyond a meagre minimum. This question will be fully dealt with in Chapter II. (d) Locating roads adjacent to but not through towns. Many instances might be given of this fact, where railway companies, in order to save money on right of way, to shorten the line slightly, or out of pique at not receiving bonuses, have built the road a mile or more away from the centre of population. Experience proves, however, that it is usually profitable to pass as near as possible through the very heart of all towns or cities, even at considerable extra expense. The engineer must, therefore, when entrusted with a study of proposed routes, have several leading ideas constantly in his mind : (i) How to obtain the most traffic, including the idea of shutting out, avoiding or fighting competitors. 1'. , Railway Enginehring. 9 (2) How to get a road built with as small fixed charges as possible consistent with small operating expenses, and clause (i). (3) How to build a road that will be operated and maintained at as small a charge as is consistent with clauses (i) and (2). These three things are intimately intertwined^ but may be affected by such considerations as obtaining heavy local aid, having heavier grades in direction of lesser traffic, and a complete change of train loads at the end of each engine division (100 to 130 miles), excepting always that the whole road will allow the passage of moderately heavy passenger trains intact. Unfortunately thes^: matters are often, erroneously enough, may be, settled quite apart from engineering ideas, politics and local aid being the controlling factors ; but facts remain, and while politicians perish and local aid, once given, looks for a quid pro quo, the railway burdened with too heavy grades, too much debt, or dis- tant from its customers, will gradually, but surely, fail in the race. The problem which has to je solved, in each case, is to create a paying property without satis- fying, often, the dangerous desire on the part of the 1 engineer to build solidly and erect monuments to him- self, or satisfy his innate desire for excellence of con- struction considered from too narrow a standpoint. This is a difficult mntter in a thinly settled country like Canada, as statistics t<» be given will show, but our roads are being more economically constructed and operated day by day and traffic is slowly increasing, so that we may confidently look forward to a time when there will be a change and some small returns for the stockholders and promoters. ARTICLE 3. — TRAFFIC. Wellington demonstrates that the traffic revenue increases with the (population per mile of railway) 2. This is based on the rough assumption that the volume of traffic increases as the distance between two towns diminishes, or that the gross traffic receipts be- tween two towns is nearly a constant, and thus if on a given line we have two traffic points and call traffic 10 Railway Engineering. I. Then with three traffic points the traffic =1 + 2, and with n traffic points the traffic = ;/ , or whenw is large we may neglect the second term and say that the traffic for;/ points = — Now if we apply this to the individual as a unit, we may deduce the general state- ment given above. This assumption is not tenable when applied to a special commodity which originates at a fixed place, such as coal. Because the traffic is the same for two t<;wns 150 miles or 15 miles from the coal pit, depending entirely on the demand for coal, on the other hand it is augmented by the fact that short haul rates are usually higher than long haul for the same service. Even this consideration, however, will not holt! at the present day for suburban steam traffic, because it is beinu terribly crippled by electric suburban railways. On the whole, it is probably still true for a road of con- siderable length of general traffic, not largely suburban. This view is upheld by the following table of the internal traffic of New York city : Trips per year Value by Year. Population. per inhabitant. ('O'^ Formula i860 814,000 1870 942,000 1880 1,206,000 1885 1,393.000 By which we see that the gross retu*"ns exceeded the ratio of {population^, but as the length of haul also increased it is probable that the net revenue about fol- lowed the law given. The following table, also, of a broader and more general character, confirms the view given : — TABLE I. SHOWING INCREASE OK POPULATION AND RAILWAY EARNINGS IN UNITED STATES AND CANADA, 187O TO I895. 45 45 122 60 175 99 ai3 13a Canada. Year. 1875 1880 1885 1890 1895 Miles of Railway. Gross Earnings 4- lU.OtjO Popula- tion -T- 10,000 4.300 6.800 10.200 13,100 16,091 $1,958 2355 3223 4.680 4.680 39- 43- 45- 48. 51- iCol.iv.)* 1,521 1,849 2,025 2.304 2,601 Rates oi Col. iii. Col. V. 1.29 1.27 1-59 2.03 I 79 Railway Enginkeking. II Year. U.S.A. J 1870 •«75 1880 1885 i83 peting road, and an exception might also be made in the case of being able to pass midway between two towns and serve them fairly well by branches. The N.Y.C. & H.R.R. is a striking example of a road much longer than any of its competitors, but with light grades and a heavy tributary population, it is largely independent of its through traffic, and can handle it as " excess traffic " at a very low rate ; on the other hand, the Pennsylvania R.R., soon after its com- pletion west, built feeders in eveiy direction, and thus held traffic that would otherwise soon have passed into other hands owing to its heavy grades. Other general conclusions regarding trunk lines are: (i) That they should never attempt to make a small sea or lake pore a terminal, but have the largest possible terminals even at the expense of considerable extra distance. As instances of this, witness the Inter- colonial making arrangements to enter Montreal, the Erie Railway abandoning Dunkirk as a terminal and building into Buffalo, and the Mexican National at- tempting to establish a port at Corpus Christi, instead of Galveston, which proved a failure. (2) That after joining together as lai^c a popula- tion as possible without unduly lengthening their line, they should build or buy such a system of branches, as feeders, as will draw to the main line as large a volume of traffic as possible, even in the face of competition. No better example of this can be given than in the Province of Ontario, where the G.T.R. and C.P.R. both endeavor to have feeders in all directions, and fight each other in many towns. Almost all the inde- pendent small lines of that Province have disappeared. Branch Lines, — Branch lines are usually unprofit- able in themselves, e.g.. Midland Railway of Canada, a network of short lines operated by the G.T.R. at a yearly loss, for the purpose of securing a large volume of freight for its main line, and preventing the C.P.R. from getting it. This is the reason, in almost all cases, which causes the most prosperous roads to operate them, to swell the trunk line traffic, because once any u H U o |w w Ic * a 1^ " .« ' -' t 1 J s If & 2L ■s ■gj •SI- ll Is e ie o e ? s SI M U H H a M c ?:;: IS%= J "I £ ft ■I o^, I' M - '^ j^ 5 Si -2 1?. Si o o •■« _■» "• Q O M iri O lA ") iri w" 'O 1*1 w 00 N 1 ! I i6 Railway Engineering. branch line trafific is delivered to tJie main line, it being extra traffic, is very profitable, often costing almost zero to handle, while the toll collected is for the whole trip. Putting the cost of handling the unit of minimum traf- fic on a main line at loo, the cost of handling a single extra passenger or small parcel of freight is almost zero : in car load lots at lo to 30 per unit, and in train load lots at about 50 per unit. A branch line, hov/ever, usually costs nearly as much per mile to build as a main line, and nearly as much to maintain — certainly far more than in propor- tion to the traffic ; so that we can usually lay down a rule of branch line location to make it strike the main line as soon as possible, but meet it at a town if possible in order to give the branch more return freight ; country junctions of branches are deadly in their lack of traffic (other things being equal), therefore branch lines should rather be numerous and at right angles, or nearly so, to the main line, than to run parallel to the main line for any great distance, stringing together un- important hamlets before joining the main stem. Volume of Tra^c. — The volume of traffic by Table III. is shown to be about $9 per heau, per year, in Canada, and $15.60 per head, per year, for the United States. We may not assume, however, that it is uniform in Canada^ but varies probably as rapidly as the square of the density of tributary population. The average town would probably be about $10 per yeai, per head, increasing to very much more for large towns and cities. The class of town also has a great effect ; an industrial lown such as Gait, Ontario, would afford far more traffic per head than such a town as Whitby or Cobourg, owing to the pursuits of the inhabitants being different. The great volume of suburban traffic cannot be counted on in the future, as the cheap road- bed, etc., few restiictions, frequent service, and con- venient depositing of passengers, enables electric lines to serve such a traffic very successfully. This is a serious problem for steam roads to face, as suburban traffic has been, in the past, a very profitable feature to many roads. Railway Engineering. 17 INCREASE OF TRAFFIC. The per cent, which operating expenses bears to the gross revenue varies enormously. Roughly speak- ing, the road which economizes in its investment, on which it pays interest, is apt to have heavy operating expenses. This percentage in Canada varies from 256 per cent, to 43 per cent., with an average of 70 per cent, for Canada in 1895. These working expenses may be roughly divided as follows : — 70 (i) Maintenance of line and buildings 15 ' (2) Working and repairs of engines 22 (3) " " cars 6 (4) General expenses 27 Now careful estimates show that only about half of these expenses are increased by an increase of traffic beyond a meagre minimum, which is the reason why it is so important to select a route giving the most traffic, as it is the increase of traffic over that which gives pro- fit enough to pay fixed charges, to which we must look for profit to the stockholders, and a very moderate dif- ference in first cost, revenue or working expenses means success or failure. In any young country like Canada traffic increases rapidly at first, the increase being twofold: (r) A natu- ral increase due to increased population; (2) An in- crease fostered by the newly discovered wants of a people not before served by a railway, the critical period of a road's history being usually the first few years of its existence, before a solid, steady revenue has been secured. In England, New England States or Eastern Canada, the growth of traffic may be estimated at 5 to 6 per cent, per year for a given line. While in Western America or any new country, 10 to 15 per cent, per year will not be too much to figure on. The usual way of estimating traffic is by the number of trains per day over roads of certain maximum grades ; but on roads of small traffic, which do not wish to run less than one train per day each of freight and passengers, the trains are not apt to be loaded well, and again two trains per x8 Railway Engineering. day will be considered necessary to accommodate the people long before they will be regularly filled, so that it is only on roads of heavy traffic that it can be divided into the number of trains that will just accommodate it. ARTICLE 4. — RECEIPTS. Referring to Table II., " Railway Statistics," it will be seen that American freight charges are lower than English with a less volume of traffic. This anomaly is explained by the frequent, lighlly-loaded freight trains of England run at a high speed, with small cars and heavy terminal charges. An adoption of heavy American cars, larger trainloads, and a slightly de- creased speed, with perhaps five freight trains per day instead of ten, would enable English freight rates to be lowered more than one-half, and effect an enormous economy. Partly due to high rates on freight, but chiefly due to enormous traffic, the receipts on English roads are nearly $20,000 per mile per year, as against $5,900 per mile per year in the U.S.A, and $2,908 per year per mile in Canada ; operations for 1895 showed net earnings to be 3.8 per cent, interest on gross capitalization of Eng- lish roads, as compared with 2.97 per cent, per year in the U.S.A., and 1.56 per cent, per year in Canada. This great difference, in spite of the capitalizations of the railways, per mile of railway, being $230,000 for Great Britain, ' $65,000 for U.S.A., and $55,760 for Canada, is due to two distinct causes, (i) volume of traffic, (2) decreased percentage of operating expenses to gross earnings due to this increased traffic, the net earnings being $8,751 per mile for England, $1,925 for U.S.A., and $873 for Canada. Let us now discuss the position which Canadian railways occupy financially, first taking Canadian railways as a whole, and, second, classifying them : ARTICLE 5. — CANADIAN RAILWAYS. The returns for 1895 are about as poor as could be selected, and those just handed down for 1896 show a slight improvement, but this may be due to temporary retrenchments, which have to be made up for sooner or later, such as track and car economies, by letting the Railway Engineering. 19 condition run down slightly. The net earnings of Cana- dian railways of $873 per mile give net receipts of $14,035,820, but the interest on bonded debts, and esti- mated amount of loans, etc., amounts to $17,168,000""' (approx.), or a net loss of over $3,130,000, and nothing with which to pay interest on the $167,000,000 that the various Governments have given either in the form of an investment in Government railways or as bonuses, and nothing with which to pay dividends on stock. This does not look encouraging ; competition and popular clamor keep rates down to the lowest possible notch, and so long as our traffic is small it seems certain that, considering the severe climatic conditions under which our roads are operated, and the evident economy of management (70 per cent, of gross receipts as compared with 67J for U.S.A.), {he pre- sent rates must be fully maintained, if not rai<3ed. The stock of Canadian railways is not all real, but estimating that one-half is real and one-half water, we have $180,000,000 invested bearing no interest, besides the $167,000,000 which the people of the coun- try have sunk in them in order to have sufficient rail- way accommodation. Even neglecting interest on all loans, floating debt, etc., there is still a deficit on bond interest of $1,252,000, which is met year by year by issues of more bonds and stock, or by creating floating debts which are periodically so converted ; we go on year by year mortgaging futurity. It is hoped that in a few more years increased traffic will enable the bond interest to be fully met, and in this the increased solidity of permanent way will greatly aid. The aver- age cost per train mile is very low (8oJc.), considering our high price of coal, severe climate, rather inferior road beds, small number of trains per day, and good wages paid ; it reflects great credit on Canadian man- agement as a whole. Let us now analyze Canadian workings by divid- ing the roads into four groups. (See Table IV). * This is based on the assumption in Table II. that the interest on loans, floating debts, etc., is 5 per cent.; probably a large proportion of it bears no interest. o t/i 1— t Q <: ?; 3.740 " 34.077 •• 3.433 " 18.9 per cant. a.6 " 87.9 '• 133 •• 136 " ao.7 " 30 " $ii6,aoo " 100 " This is an extreme instance, as grading was light and equipment expensive; the items affected (i and 2) are only ai^ per cent, of the total, and probably 25 to 40 per cent, will give a good average for ordinary single track roads. Each country traversed is suited to certain maximum gradients, and an endeavor to modify them extensively will bring very heavy additional expenses, but within narrow limits, such as a change of ruling grades by as much as ^ or ^g per cent., the advantages of a liberal ex(>enditure of money to obtain the lessp 'rade are often overlooked and the ' penny wise " max 'opted. Every engineer who has the decision of the ruling grade should study such figures carefully, and by as extensive surveys as possible determine what is the least ruling grade that he can get at a cost which will be justified by present or expected traffic, always, of course, considering bow much money can be got at all, for no expenditure can be justified that will in any way endanger the successful completion of the road ; he must consider each item of expenditure or economy, per se, whether it is wise or not, remembering always that it is the difference of gross receipts, working expenses and fixed charges that is to be thought of in determining the best general route. Note, however, that these calculations and estimates do not hold strictly true for roads of very light traffic, be* cause some trains must be run in any case to accommodate traffic at certain intervals, and if they are not fully loaded, then an increase of grade will not have any effect until it causes an increase in the number of trains, as a change in the rate of grade dotss not usually mean any increase in the total rise or fall. Railway Enginbkrino. 43 In comparing two routes for costs of operation the best method is to assemble the curves and grades of differ- ent classes and take their differences, pro or con, also the difference in the number of trains per day necessary to handle the probable traffic. These differences multiplied by their proper multipliers will give a comparison of how much more valuable one route will be than the other for a given traffic, and will determine consequently how much more can be justifiably spent to construct one route rather than the other, other things bting equal. In such a com- parison it will be found that any difference in the ruling grade is usually the preponderating item. r I' 44 Railway Engineering. / CHAPTER III. Curves. Ill J ARTICLE 8 — ViiRTICAL CURVES. Wherever there is a change in the rate of grade there must be a vertical angle or a vertical curve. If this change is slight, less, say, than -^ feet per loo feet, no need exists, either on construction or afterwards, of doing anything more than to let the trackmen put in a slight curve by eye, but when the change is of considerable magnitude, care should be taken, both for the sake of appearance and also for safety, that a regular vertical curve unites the two grade lines. In the past, in America, this has not been often done. If ascending and descending grades were to be united, a short piece of level grade was inserted at the summits and in the depressions ; anything further was, curiously enough, relegated to the track gang as being a refinement unneces- sary for a civil engineer to bother with ; the track or sec- tion foreman, with greater appreciation of the real need for a regular increment of change from one grade to an- other, did the best he could and put in vertical curves by eye, which moderated the ill-eflfects of such neglect. Wellington has ably dealt with the subject, at length, from the standpoint of the link-and-pin coupler, and demonstrates that the vertical curve which is needed, theoretically, is one which will change the rate of grade from the front to the rear of the longest trains run over the road by an amount not greater than the grade of repose (the grade of repose is that grade down which a train will just keep moving under its own weight, and is about j"^ per cent, for loaded trains at a speed of 25 miles per hour, and increa: is with the speed). He reasons thus : Taking the train as a whole, each car will momentarily crowd toward the one in front of it, and Railway Engineering. 45 so on throughout the whole length of the train, putting it in a state of compression, with slackened couplers if the grade resistance at the front of the train is enough greater than at the back end to exceed the grade of repose. This is based on an assumption of uniform engine power, and should the engine driver increase speed just at this /n>^.ft. m.c too r/^fz. instant, when everything J? olack, the tendency will be to create severe jerks and oscillations causing derailments. This reasoning refers entirely to a grade depression, whereas at a summit the reverse will happen and the couplers will be momentarily strained much more than normally. From these premises we can see that the vertical curve at summits may be arbitrary in amount and much sharper than in depressions. Probably a change in rateofgrade of-^ per cent, for each loo feet is not excessive, 46 Railway Engineering. I !■ and may be inserted either as a complete curve joining the ascending and descending grades (see Fig. 8), or if the summit level is long it may be divided into two portions (see Fig. 9). When, however, a descending grade is to be united to a level or ascending grade, an accurate calcula • tion should be made for reasons already given. For in- stance, supposing that the longest train on the road will be 500 feet (engine and 14 cars), then ,'^ per cent. « 100 500 = ^^ per cent, change per 100 feet will be the amount strictly demanded for complete safety on a road of the given length of train using link and pin couplers. But as automatic vertical plane couplers, with practically no slack, come more generally into use, which is only a question of a few years, the need for such extensive curves will not bo imperative, and a vertical curve changing more rapidly will answer fully, when a longer curve is difficult to obtain. Usually, however, a level grade between the descending and ascend- ing grades is required, because a structure should always be placed on a uniform grade from end to end, and as they are usually in the depressions, this limits the vertical curve in such cases to two short pieces joining the level grade to the others. (See Fig. 10.) If there is no break in the embankment a continuous vertical curve is much better from every point of view, and should be put in as in Fig. II. On roads having only light grades, and consequently heavier and longer trains, the rate of change in depres- sions will be very small, and circumstances will determine whether the full amount can be put in without excessive cost ; but with light grades and easy vertical curves, the distance which the middle of the curve will rise above the point of intersection is sm?.ll. It may be calculated, in any case, in the same manner as the middle distance in horizontal circular curves, if the vertical curve is treated as a circle, or if treated more precisely as a parabola, it may be stated at once as half the distance which the apex is from the middle of a chord drawn from one end of the vertical curve to the other, this being a fundamental property of the parabola. Railway Engineering. 47 (a) Treatinpf the vertical curve as an arc of a circle, calculate first the permissible change in grade per loo feet divide this into the total change of grade, giving the total length of curve, ^ of which will be on each side of the apex of grades ; then the position of the curve for each ICO feet relatively to the tangent lines may be obtained graphically on a large scaled drawing, or calculated more precisely as in ordinary horizontal circular curves. (6) Treating the vertical curve as a parabola having a constant rate of change of direction per loo feet, is more precise and more convenient. Calculate first the length of curve, which will be the same as in (a), and then pro- ceed as follows : Let the change of grade per loo feet = R. Then referring to figure 12 — , the departure of the curve from the tangent will be ^R, 2R, 4iR, 8R, la^R, etc., till the middle of the curve is reached, after which the distances from the second tangent will recede .... la^R, 8R, 4JR, 2R, ^R, to the other end. It will be seen that by the latter method the elevations are always in even units or portions of units, and the rise of the curve above the tangents is given almost by inspection ; for convenience the length of a vertical curve should be fixed at the nearest even hundred feet, so that the curve may be divided into two equal parts of exact hundreds in length. Such ver- tical curves, with their elevations once established, will be no njuie difficult to place on the ground and build to than a succession of straight lines with abrupt changes in grade, and will gi\e a track safer in depressions, having better drainage in sun mit cuts, nd better in every respect, but increasing the cost of the road-bed slightly. ARTICLE 9. HORIZOr TAL CIRCULAR CURVES. It is not necessary to treat here of the mathematics of the circle. There are several en aeering field books which have considerable space de\ v^ted to methods of placing curves on the ground under ordinary or exceptional cir- cumstances. Some of these books also contain, in addi- tion to ordinary mathematical tables, tables of external secants and of sub-tangents for each degree of curve, and for each interval of one minute in the total intersection ' il 48 Railway Engineering. angle :'ii I 14: these books are great time-savers in field opera- tions, and should always be used. In placing curves on the ground, it is preferable to establish the two tangents first, intersect them and meas- ure in the BC and EC from the intersection or apex ; then the curve can be run in from either or both ends and any error minimized. With very long flat curves on unstable ground, it may even be preferable to fix the middle of curve from the apex by measuring in the external secant, and then run the curve in from the ends and middle; the method sometimes adopted of running a curve in from the BC, and deflecting on to the second tangent at the EC, is very liable to establish it erroneously. Another very important point is the method of keep- ing curve notes. The vernier should always read half of the total deflection of the curve from the BC up to the point on the curve toward which the telescope is pointing ; this is a constant index of the position of any point. This method necessitates loosening the vernier-plate at each set-up and re-setting it to read the index reading of the back-sight ; but it has the all important feature of enabling a transit to be set up at any point on a curve, and being sighted to any other point with a certain knowledge of what the vernier reading should be. Curves can be run in back- ward as easily as forward. Any other method of keep- ing notes will be found, in the end, less reliable and con- venient. Whenever curves are sharper than 4° or 5* it is better to put in stakes every 50 feet even on easy ground, as the difference between the length of chord and curve for 100 teet measurements would be consider- able ; it is also convenient for cross-sectioning. In running in sharp curves, particularly curves having a large inter- section angle, the greatest care is necessary in the chain- ing ; poor results in checking up at the EC are usually traceable to the errors in measuring the subtangents or the curve itself. It is often necessary to replace stakes that have been lost, or to put in intermediate stakes on curves without the aid of a transit ; whenever this is the case it is valuable to remember the following formula, which is approximately true for all curves usually used on steam railways : ■«l Railway Engineering. 49 It is O = .218 N^D (11) Where O = oflfset from middle of a chord to the curve (in feet) N = length of chord in 100 feet. D = degree of curve. Or, if simpler, remember that the offset from the middle of a loo-feet chord on a 1° curve is .22 feet, and that (i) Offsets vary directly as the degree of curve. (2) Offsets vary as the square of the length of chord, which is true up to 200 or 300 feet chords. (3) Offsets, inward to a curve, from a prolonged chord are 8 times the offsets from the middle of the same length of chord outward to the same curve. This is illustrated in Fig. 13. Circular curves are in general use on railways, but there have been isolated attempts at using the parabola, which have not been found satisfactory. The idea involved in its use v^as to have a curve of easy radius at the ends and sharper in the middle, but the train did not travel steadily, being in a constant state of change from begin- ning to end of curve. It has been found from the very first days of railroads that an annoying and dangerous jolt, sidewise, took place as a train either entered or left a curve, and the parabola was a first or rather a mistaken idea as to remedying this evil. Instead of this, the concensus of opinion has fixed itself on the use of the circular curve, but with the modification of the use of easement curves at each end of it to join it on to the tangents in such a manner as to modify or wholly dissipate any disagreeable shock which would occur if the curve were to change instantaneously to a straight line. In the past the trackmen have been allowed to introduce these easements themselves in an approximate and make- shift manner, but at present there is a growing feeling that an accurately calculated and placed easement curve is necessary, especially as passenger speeds are becoming higher. Easement curves have been used for many years in Europe, and are becoming quite common in America. ARTICLE ID. — EASEMENT ON TRANSITION CURVES. In article 6, under " Curve Resistances," is given for- mula (8), which indicates the amount that the outer rail 4 :'il 1:1 If 50 Railway Engineering. I:!.! on a curve should be elevated above the inner one, but, as the two rails on the adjoining tangents are of the same height at any given point, the question arises as to the best manner of effecting this change of conditions so as to lessen any shock to passengers or rolling stock, or indeed to entirely abolish it. Practice has determined that, where there is distance enough to permit, the curve super-eleva- tion ought not to be lowered more than ^ inch per rail length (30 feet), or {e.g.) on a lo** curve of ^ inch super-eleva- tion per degree, this would require a distance of 300 feet. The most common practice in America has been to bring the full elevation to the ends of the curve, and then lower it on the tangents. This, evidently, will act so that as a train approaches a curve the play of the wheels (^ inch to I inch) will all be at the outside, i.e., the wheels will press against the inner rail, and then, at the instant the curve is reached, there will be a lurch to the outside in assuming the natural position, in passing round a curve, of the front wheel of each truck against the outer rail. Some have tried to remedy this by lowering the eleva- tion partially on the curve, and partially on the tangents, which merely divides one shock into two smaller ones. The true remedy lies in not making an abrupt change in horizontal alignment from a curve to a tangent or vice versa ; but in so arranging the track at each end of a curve, that commencing with a curve of infinite radius, this radius is gradually decreased, i.e., the curve is sharp- ened, and at the same time, the elevation of the outer rail is increased, keeping this elevation at each point just sufficient for the curvature until a junction is made with the main circular curve, with a curvature equal to it, and with a full elevation, and having kept an equipoise be- tween curve and elevation at each instant, all lurches and shocks will be avoided. That this is the only true and rational solution, is proven by the fact that practical trackmen, unguided and even hindered, often, by engineers' rigid centre stakes, but recognizing the evil and its remedy, have introduced crude easement curves wherever they could do so, and improved the situation as much as possible ; but as the tangent and main circular curve were both fixed in position by construction, all that could be done was to flatten the ends of the curve at the expense of the Railway Engineering. 51 adjoining portions, which were thus made sharper than the main curve itself, and formed more or less of elbows in the track, often 2° or 3*^ sharper than the main curve. Now this can be avoided by moving the curve inward bodily, or by changing the position or direction of the tangents, or by sharpening the whole curve slightly, any of which will permit of the introduction of proper easement curves at the two ends of the circular curve. Many methods have been advocated for putting in these ease- ments, the endeavor being to simplify the process, in point of time and mental effort, and still preserve the essentials. Some of these are : (a) A succession of short pieces of curves of decreasing radii, (b) A modification of (a) in the form of a spiral, (c) A modified quadratic parabola (Holbrook spiral), (d) A modified cubic parabola. As any one of these can, when once understood, be easily laid out in the field, it is only necessary to decide on the most adaptable and suitable one for all cases to be met with, and study its theory and actually use it, after which its seeming difficult nature and laborious methods of applica- tion, so long dreaded by many railway engineers, will be found quite simple, and capable of rapid manipulation. Almost all engineers are agreed that transitions are intrinsically necessary, and on European and the best American tracks their use has become established ; the chief objections to their general adoption here have been the deeply rooted ideas that they were difficult to apply and too refined for ordinary use, but as speeds are being increased and competition is keener, they are beginning to be used by all roads of any importance because the conse- quent easier riding caters to the travelling public and also because the wear and tear on the rolling stock, and the difficulty of keeping the ends of curves in proper line, are thereby much decreased. (a) This first class of transitions does not require any demonstration. Some engineers put 100 feet or 200 feet of a curve of larger radius at each end of the main curve, and trust to the trackman for the rest, others introduce a series of short arcs of decreasing radii, say 30 feet of 1° curve, 30 feet of 2" curve, etc., leading up to the main curve at the rate of 30 feet per degree ; this necessitates issmm 52 Railway Engineering. I ; i! placing the transit every 30 feet, is a tedious and clumsy method, and the result is that the trackmen fuse one portion into another until it is, to all intents and purposes, the same as a spiral. It does not admit of ordinary calcu- lation or manipulation unless modified as in the next para- graph. (b) In •* The Railway Spiral," by Searles, is given a complete analysis of the transit work necessary to lay down a succesion of short circular arcs, beginning at zero, and having equal lengths of arcs of equal increments of sharpness, e.g., 20 feet of 1° curve, 20 feet of 2" curve, etc., up to any required sharpness. Tables of deflections are worked out, so that any point of change of curvature can be used as a transit site, and any point of change can be established from any other point of change by transit deflections. Methods of conversion are also given, so that from one foundation series other deflection tables may be determined suitable for spirals of more or less rapid sharpen- ing. The subject is well discussed and thoroughly worked out for all probable conditions, but as it does not present that same flexibility and simplicity of use which the cubic parabola possesses, its continued use is doubtful. It has served its day, and, where used, furnished the trackmen with a succession of hubs, really the ends of arcs of increasing sharpness, but practically points on a spiral very suitable for an easement curve. (c) The Holbrook spiral (quadratic parabola). The idea involved in this easement curve is that the vertical acceleration of the train, as it passes around it, should be uniform. If we let / represent horizontal distances (with train moving at a uniform speed) in the general formula s = ift.2, then, in order to keep/ (acceleration) constant, the distance, s, (i.e.) the amount which the train rises above the normal tangent level, must vary as the (dis- tance) 2, and as the elevation should always bear a con- stant ratio to the degree of curve at each point, therefore the degree of curve on this required spiral must vary as the square of the distance from the zero of such a curve, (i.e.) the radius of curvature, at each instant, mus^ vary inversely as the (distance)' from the zero of the curve. A curve of such a nature has the equation y = [f)x^ to represent it, and is a curve very flat at the beginning, Railway Engineering. 53 but increasing very rapidly in curvature. This easement curve sacrificf s the correct horizontal alignment, as will be seen in the next paragraph, for a supposed refinement in the vertical one ; it is quite difficult to apply except in most ordinary cases, as the formula) used involve expan- sious of sine and cosine, does not present any advantage over the cubic parabola, and is not so adaptable or easy to manipulate in the cape o{ any problems having special conditions. [d) THE CUUIC PARABOLA. This curve as adapted to transitions to railway circu- lar curves has been studied pretty thoroughly. Howard, Armstrong, and others have written pamphlets on it ; the transactions C.S.C.E. for 1891, 1892 and 1893 bave several papers and discussions on it, and its probable originator, the late A. M. Wellington, determined very simple equations for it which were published in the Engi- neering News, January and February, 1890. It is this last demonstration that will be now given to which will be added necessary developments. The curve required for a suitable transition is one which start- ing with an infinite radius or D (degree of curve) = O. at the D T C {A Figs. 13^ and 14) has a degree of curve at each point in direct proportion to its distance from the B T C until it joins and becomes langent to the main curve at C, and is, at that point, of the same degree of curvature as the main curve. The cubic parabola y = (/) -v"* approximates to these conditions. Let A M C (Fig. 13^) be the cubic parabola, .r4 C* tangent to it at A, and / C the radius of the D degree curve with which it connects at C, having there a com- mon tangent H C. Let X be the central angle of the circular arc P C, which is changed into the transition curve A M C. Let E P G be tangent to P C at P and therefore parallel to ^4 C^ and make C C^ perpendicular to A C. Also in Fig. 14, let vertical heights represent degrees of curvature at any point and horizontal distances, measurements along the cubic parabola. 54 Railway Engineering. PiauRB 13^. I '1 I ' I / I / I / /■*gte»J0i ^''g<"^./S mSart. y* V *»•>*» ^»gvnt. m Then the rectangle D B will represent graphically the circular arc P C, and the triangle ABC represent graphi- cally the cubic parabola A M C, and from this diagram and Fig. 13^ we may readily conclude : (i) Beca"'se the total angles of the arc P C and the transition A M Care equal, therefore the area of the triangle ABC must equal the area of the rectangle D B, and Railway Engineering. 55 therefore a transition curve is always twice as long as that portion of the circular curve which it replaces. (2) Because the triangles A M N and C D N are equal and similar, therefore the angular deflections or off* sets from the tangent to every point '\t\ A M (Fig. 13^), and from the circular curve outward to every corresponding point in the equal distance C 3/, are equal in magnitude and distribution, and .*. D M is equal to M P and half of D P (Fig. i3i). Hence the offset or shift D P {= O), and the transition curve A M C bisect each other at M. (3) The offsets from a tangent to a circular curve vary as the square of the distance from the tangent point (nearly), or to formulate it O varies as m« D. Where O = offset from tangent, n = distance of the offset from the tangent point, D = degree of curve, but by our definition of a transition curve the degree of curve at any instant also varies as «. Therefore in a tran- sition curve of this nature O varies as n^ x n = n^ (12), and also by paragraph (2). If we have a given offset from tangent to circular curve at D = D P ( = O), then the off- set to the transition curve at a distance m from A is I mY O equal tr - — where « = J length of transition = A M = M C. And, in the same way, measuring back from C along the curve toward P at any distance, m the offset out ward from the circular \n I 2 The equation to the cubic parabola can now be established in terms of the offset O and \ length «. O O I let y = C x^, but when y =—-,a; = H, therefore C= — X — curve to the transition curve = (13) n. and 0^ X'^ (14) (4) because by equation (12) offsets to a transition curve vary as cube ot distance from origin, therefore in Fig. (13) CCi=8 X DM = 4 0, and therefore GC = 3O (15) Now, for very small angles, G C = P C x Sin — (nearly), and P C = 2x I C x Sin — (nearly), therefore by ) .1 \i Hi i.fi IF n n H a' 56 Railway Knginbbring. substitution we get GC-30 = 2/C X Sin" — (nearly), but /C- -^y^ {D ■ degree of curve), and ;. O ■ ^tj- «« Sin« — and ^. X p~x D Sm T"'N 3820 = -^^^^^ ^^ ^ '^ ('6) from which we can get X, having O and D ; or otherwise, X X since n = jy (evidently), and for small angles Sin — = .0087 X (in degrees). .'. substituting in (16), we get .01618 / — - — ~ , ^= .0087 ^O X Z) = 1.86 l^Ox/; (17) and w = ^ length of transition = 1.86 _^_ = ^•86>]^. (18) This can also be put in the approximate form, ^=6^ (^9) Where R - radius of the curve. Equations (12) to (i9)give such relations between A',m, O and D as will enable any length of transition curve to be put in for any degree of curve. (e.g.) Let D - 10° curve, and O = 10 feet. Substituting in (18) we get, n = 186 feet, or the tran- sition is 2M = 372 feet, which is somewhat longer than is needed. {e.g.) Let X = 15°, and D = 10^ curve. Then, O = / ^o^fo !/ = 6.5 feet, and n = looXi.SsJ— ^ = (i.86)»Xio -^ ^10 150 feet, which latter could have been determined directly. Also — = ■~ = 3«25 feet, and any other offset will vary as cube of distance from A ; that at the quarter points being, for instance, (^) 3x3. 25 = .41 feet. A most usual length of transition is 30 feet per degree of curve, which permits of the super elevation being lowered at ^ inch per 30 feet = i rail length, which is a most usual amount. Railway ICnoinkkking. 57 Now, although these equations enable us to put in transitions by offsets, if we have for instance, the tangents already in place, and can move the main curves inward bodily so us to permit the requisite ''shift" (), which is very useful if, on construction, the rigid curves and tan- gents are found already in place, and offsetting is the quickest method to use — still, we also wish to he able to put in transitions as a regular part of location, and not as an afterthought, and to do so it is necessary to determine methods of locating such curves by transit deHections from the beginning, end, or intermediate points. Any small angular deflection from a meridian to any offset . , , , , point varies as -p— , or in other words the natural ^ distance tangent of any small angle is its circular measure. Now referring to equation (12) and Fig. (13^) any off- set from the tangent A C to the transition curve varies as the cube of the distance from A. :. angular deflections to the transition curve from offset tangent A C, using A as origin, vary as distance (distance)'. (distance) 3 distance Also in iMg. (13) ^-^ (evidently) 6x0 X = but the angle C'AC = G C P C >c 2 x_ 2 ^ 3 2 (20) X O n 91£ 4x0 2 >t n O n the angle C AC = — x ^ 3 O n = 7^^ (21) let a 10"^ curve have a transition curve 300 feet long Equations (20) and (21) enable us to determine any deflections to the transition curve from the point A ; (e.g.) a n 300 I 77 = ~2~ .'. by (21) theangle C/.-4 C = 5'^ = 300' = deflection from tangent at A to the end of the transition, and by equation (20) the deflections to each 30' intermediate point are : thenX = 10 -^ smH^-^ 58 Railway Engineering. ist 30 ft. point (-^ — I X 300' = 03/ \ ^00/ 2nd 3rd 4th (12^' X 300/ -1X2/ \ 300 I (-^2_| X 300' = 27/ V 300 / (i^^r X ,00/= 48' etc., etc., etc., etc. This series of deflections from the origin A , continued as far as necessar}', may be called a foundation series, and is the basis of all deflections forwardjor backward from any point. We must now, in order to fix on intermediate de- fections, with the transit ah at some intermediate point, look on a transition curve, thus : (See Fig. 15). Suppose li to be stopped at i, then it is a transition curve to a 1° curve ; if stopped at 2, it is a transition curve to a 2° curve, etc. ; therefore if the transition does continue past ihe points i, 2, 3, etc., we may consider it to be composed of two par*s : ist, a i*^, or 2'', or 3'', etc., curve, according to cirrumstances. 2nd. Pliis the foundation series oi 3', 12/, 27', 48', etc., beginning at the point considered, and continuing forward to any desired extent, and the transition curve deflections are the sum of these iwo. Also, in the same way, the transition curve deflections looking back- ward, with transit at any poiut, are those of a certain de- gree of curve corresponding to this point, minus the same foundation series ; (e.g.) suppose the transit to be at the point 3, with the vernier at zero, and line of sight tangent to the curve, then the vernier readings to each inter me- diate point would be — m yioo 2 ' 60 100 180^ 2 180' 2 180' -12' = )= -0^54'. 0°42'. / \^ 0° 24'. (3) o^ o' = 0° o position of transit. /30' 180' > (4)+ i^><-2- + 3M= +o°3o'. Railway Engineering. 59 (5) + (, 60 180' 00 2 ^ . go 180' / 120 180' (7)+(x^o^-2-+48' = +i°o6'. = +i''48'. = +2° 36', etc. In this way a table can be prepared giving deflections to be made to any point (every 30 feet), with transit located at any point. These tables are conveniently made out by Mr. Armstrong, for 30-foot chords = i rail length ; but different foundation series and different tables may be made out, or special calculations made by equations (12) to {20) for a transition curve of any rapidity of sharpen- ing, but of the same nature and handled in the same way. This is often necessary where there is not room between the BC of one curve and EC of the previous one to permit of the introduction of transitions which sharpen so slowly as 30 feet per degree. In street railway work, for instance, transitions sharp- ening from o" to 20°, or even 40**, etc., are needed, and must not occupy more than 20 or 30 feet in length. Special corrections must be applied in such a case, and even for steam railways Mr. Armstrong has worked out correc- tions in lengths to apply to the very approximate equations here given, but as the correction is zero until an 8° curve is reached, and only i foot in 300 for a 10° curve, it is hardly worth taking account of here. Any one desiring extreme accuracy for curves from 8^ upward, are referred to J. S. Armstrong's pamphlet. The three problems most frequently met with in prac- tice are briefly as follows : I. (See Fig. 16.) To keep tangents fixed and to move the circular curve inward, retaining the same degree of curvature. In this case, take an arbitrary offset or length of transition, and determine the other unknowns by fore- going equations. The distance from the apex of tangents to the B T C consists of three parts : (a) Sub-tangent of circular curve = R x tan — {R = radius). H>T 60 Railway Engineering. (b) Correction of shift =■ O x tan — . (See Fig. 16). {c) \ length of transition = w. The amount in (6) is usually very small, unless is large. 2. (See Fig. 17.) To keep the circular curve fixed, and move out the tangents either in direction or position, or both : If the tangents are moved outward and kept parallel to their original positions, proceed as in (i), except that the correction of shift (6) does not exist. If the tan- gents are not moved outward parallel to their original positions, but pivoted about some distant point, then cal- culate the angle pivoted, and continue the circular curve through an equal central angle. So that a tangent to the curve at the new B C or R C would be parallel to the pivoted tangent ; then measure the amount of shift O, and by the ordinary equations calculate the unknowns ; the amount of shift O could be calculated without any field work. No correction of shift is here necessary ; this sec- ond case is most usually met with in revising location, and is very convenient often in the final slight movement of tangents or curves, by avoiding the running over ag-iin of the whole circular curves, often situated on a rough hill- side or heavy bush, and yet enabling a tangent to be moved on to better ground. 3. (See Fig. 18). To sharpen a curve and introduce transitions, so that the track will not be altered in length ; this problem is the one met with in re-running old track centres where transition curves have not been previously used. The method of solution is to assume an external secant slightly less than the original one, by an amount = expected shift, O, + an arbitrary amount of five inches to ten inches, depending on the sharpness and total central angle of the circular curve ; then calculate the transitions and complete position of a curve of assumed external secant and given total central angle, and, either by plot- ting or calculations, determine whether this new curve will cross the original one about at the ^ points and give the same length of track, thereby minimizing the movement of the track. If in error, a second trial will give usually satis- factory results. This method will often be found to give Railway Engineering. 6i transitions, which, unless the central angle is large, will occupy the whole central angle, leaving no circular curve at the centre. As this is not desirable, it is preferable in a case of this kind to use shorter and sharper transitions, so as to retain a considerable portion of circular curve at the centre. While these are the three usual problems to solve, others may arise such as introducing a transition at a point of compound curvature which needs special solu- tions. For further details, the reader is referred to the literature already mentioned, and the engineer, young or old, who has not used transitions in the field, is advised to become familiar with some one of the forms given, and ac- tually put it into practice, when its seeming tediousness and difficult nature will disappear. He should recognize that, as he would be quite ready to spend a few hours ext/a now and then, during railway construction or maintenance, on trivial matters such as affect the general appearance of the road only, and are not really important, he should be far more willing to give much additional labor and attention to such a question as this, when the returns will be increased comfort to travel- lers, decreased wear on rolling stock, and greater ease in retaining good alignment at the ends of curves. When- ever transitions have been used, their beneficial effects have at once been recognized, and, once established, track- men maintain them easily and instinctively. Some of the oldest and most conservative of the American roads are now engaged in introducing them on their main tracks. H^* 63 Railway Engineering. CHAPTER IV. \ I I ARTICLE II. -SURVEYS. The final determination of the exact centre line of a railway roadbed and track is only reached after a process of sifting, which extends from the first thought of the necessity for such a railway until the track is laid. Roughly speaking, it is usual to divide the operations into three stages, which, however, often overlap each other, or are again divided into subsidiary steps. These customary general divisions are : (i) Reconnaissance. (2) Preliminary or Trial Line Surveys. (3) Primary and Revising Location Surveys. ARTICLE 12. — RECONNAISSANCE. Reconnaissance may be said to begin after it has been decided that there is a necessity for a railway between two given terminals, or along a given route. In the latter case, local considerations, or the short- ness of the distance, or the existence of a definite water line route, may limit the scope of explorations, but looking to the larger problem, where an engineer has to determine what is the best route between two terminals several hun- dred miles apart, the study is interesting and one requir- ing a high order of talent. If the country to be traversed is unsettled, or thinly settled, the problem is simplified by lack of railway competition often, or even by considerations of traffic, but it then demands a close investigation of the natural resources of the country, which, though dormant, will be developed by the railway itself, and it might be considered best, all things considered, to build sometimes, at a sacrifice of distance, grades, or capital outlay, through a country of great natural resources, rather than through a barren one by a route physically superior. On the other hand, through a populous country, the question is much Railway Engineering. 63 more complex, by reason of the existence of other railway routes already established ; but, on the other hand, simpli- fied by a more or less well defined trend of population, which indicates the probable future distribution of people in accordance with natural laws. For these and many other reasons, exploration should commence and be well under way, or even completed, before instrumental work commences ; it should, at least, be completed for such a distance that some critical place has been reached through which the final location must pass. In order to finally fix on the best route between two defined points, it is necessary to study a wide belt of country ; even a great number of trial routes will not answer so well, because portions of various routes may be finally selected and joined together. In order to explore such a wide belt of country, use must be made of all exist- ing maps. These when made from governmental surveys will be found of extreme service as a skeleton on which to build such additional information as may be necessary to complete the study in hand. All streams, summits, passes, etc., within the extreme margin of possible routes should be accurately fixed in plan and elevation. A knowledge of the classes of timber, stone, and excavations, and of difficult river crossings, etc., should be included, and from such data, together with closely estimated lengths of lines, ruling grades (obtained from barometer heights), probable traffic, cost of construction, difficulties of maintenance and dangers of future or present competition, a selection is made of the two or three most favorable routes, over which it is thought necessary to make instrumental surveys. In carrying out reconnaissance, the instruments re- quired will depend on the class of work to be done. These should always include an aneroid barometer, a Locke level, a pocket or prismatic compass and a field glass ; distances may be determined from maps, if exist- ing, by pacing, by the rate of travel of a horse, or if in open country, it will be better to take the time to deter- mine them by stadia or some form of telemeter. The aneroid barometer is an instrument supposably compen- sated for temperature, and under static air pressures capable of always reading the same at the same altitude ; 64 Railway Engineering. ' ll;l ! ) but errors in graduation, in workmanship and adjustment, and the barometric changes going on in the atmosphere make it far from a precise instrument. In order to make it available, each instrument when purchased should be rated alongside a mercury barometer, and only those which have a reasonably uniform and small rate of error should be accepted, so that a table of such errors can be prepared and used in conjunction with actual readings taken. Aneroids in high altitudes are often much in error, and generally speaking, should be used to obtain differ- ences in elevation rather than actual ones. If a barometer is read at the same spot every hour for a day, a continual flu'-.tuation will be noticed, even during bright dry weather and very much more so during periods of storm or change ; these readings if plotted may be termed the diurnal gradient. It is evident, therefore, that readings from an aneroid taken at various places, at different times, even during the same day, will rot be reliable, and in order to make such readings of value, there should be another stationary aneroid read at regular intervals, and the readings of the moving aneroids corrected according to the fluctuations observed at the central point. Should only one aneroid be available, it would be better, where possible, to make two or more determinations of the same points at different limes, to get an average, and to work only when the atmosphere is in a settled condition. Equipped with the above-mentioned instruments and one or two assistants, the engineer on reconnaissance should go into the field free from prejudice ; the well-known wagon road or trail may be very convenient to travel along, but not necessarily in the vicinity of the best railway location ; the river flowing between or in direction of the termini may have precipitous, treacherous banks, be crooked in alignment, and afford not nearly so feasible a route as the upland country adjacent ; just beyond a certain forbidding range of hills may lie a direct and cheap route, and a pass through the barrier may really exist, being hid in the dis- tance by an overlap. In fact, the frame of mind suitable for such an undertaking should be optimistic, ready to be- lieve that if only time enough is available, the best route can be found, but at each moment doubting that such a route is yet discovered. Railway Engineering. 65 In addition to those general economic considerations which have been touched on in previous chapters, it is well to remember, amongst other things, (a) That lines following large streams will usually re- quire heavy bridge work and masonry in crossing tribu- taries. (b) That one bank of a river may be much better than the other, and that it may even pay to cross the river at rare intervals to secure alternately favorable stretches of construction. (c) That lines on side hills are more costly to maintain than those through level country, owing to the sliding and washing that takes place. (d) On the other hand, that a cross-country line, usually, will cross many summits, and even when skilfully located, and olten at a considerable loss in distance, will abound in curvature and maximum grades. {e) That in each locality will be met men who have an intimate knowledge of the minutiae of the surrounding country. Many of these look on themselves as born locat- ing engineers, and while their ideas on grades and curves are usually misty, every shrewd engineer will not be averse to the valuable aid which such men voluntarily offer ; the only difficulty lies in sifting the wheat from the chaff with- out giving personal offense. (/) That the engineer of reconnaissance and after- wards of surveys is the first officer of the railway company to be thrown in contact with the people who are to become the future patrons of the road, and, as such, his manifest duty is to make as many friends for his company as he can, consistently with his other duties, and enlist their sympa- thies m its favor ; in this way a much more reasonable spirit will be created which will display itself when right- of-way questions begin to arise. After a complete study of the intervening country has taken place, a rough sketch map should be made from the notes taken, and other existing ones, on which will be shown the positions of all streams, summits, etc., with elevations marked at critical points, then possible routes will be indicated, calculations made of the length of lines, 5 I 66 Raiiavay Enginf.ering. i) , : V.h maximum f,'racles, probable amounts of curvature, approxi- nate cost of constructions, present and future traffics, etc., all of which, although much in error, will usually narrow down the question to two or three routes which are selected as the most likely and suitable ones for instru mental surveys. ARTICLP: 13. — PRELIMINARY OR TRIAL LINE SURVEYS. The roughest class of preliminary survey may be an amplification of reconnaissance, in which a small party of three or four men pass rapidly over several proposed routes at a rate of five to fifteen miles per day to determine what grades can be obtained before more accurate survey begins. In open country rapid progress can be made, using stadia for distances and using vertical angles for elevation or depression, vvhicii are checked by an aneroid barometer. In a wooded country the distances will be determined more rapidly by chain and compass, and heights by an- eroid. Side slopes may be noted at difficult spots by some form of clinometer. What is usually wanted is to know what grades can be obtained at certain critical points, in order to ad )pt a ruling grade for the route. The instru- ments required are a light transit with stadia hairs, com- pass and vertical arc, a stadia rod, an aneroid barometer, a clinometer, a 100 ft. steel chain and 50 ft. linen tape. On this class of work the error of stadia measurement should not be more than i in 1000, which is more accurate than rough chaining. When a full survey party for instru mental work is to be equipped, a variety of causes tend to determine the men and instruments required. (a) In an open rolling country. If contour lines are not needed, the party will usually consist of — Chief of party, Transitman, Engineers, preferably all experienced. Leveller. J Rodman, Front Picketman, 2 Chainmen. Active younsr men, preferably educa- ted college graduates, not afraid of work. 2 Axemen, ) Seasoned workingmen, used to bush life, I Stakeman. ) axes, and hard work. If under canvas, add one cook and one assistant cook, and in this kind of country always use a transit. Railway Kncwnkkrini;. (6) In thickly wooded country, without iron ore, better results, for the same labor, will be obtained by using a 1 2-inch to i6-inch compass, instead of a transit, avoid- ing many detentions, useless cutting of trees, etc. The compass has no cumulative error, and will give good results where no contours are taken ; if contours are to be taken, it is better to establish a transit line for future use. In a wooded country two or three extra axemen will be needed to make rapid headway; the front picketman also, in this case, should be an expert axeman, and lead the others. (c) If the country is much on side-hill, another party is needed in addition to the transit and level parties, whose duty it is to take contours. In the past contouring has often been omitted, and although there have been some men of great natural talent and long experience who have been able to locate well, even through very rough side-hill country, by eye alone, yet even to such men a properly con- ducted contour survey would have been of great advan- tage. It is becoming more fully realized every day that a contour map, with a location line laid on it in the office and revised afterwards, where necessary, in the field, is a very valuable part of preliminary surveys in such a kind of country. This topography party consists of two or three men, equipped with a level board, level rod and hand level, or else with a clinometer and tape to measure side slopes ; the work is carried on one day behind the level party, and the method of procedure is somewhat thus : Detached sheets of paper about i8 inches by 24 inches, have plotted on them the centre line and level height at each 100 feet and hub, according to the previous day's records ; these sheets are mounted on a drawing board and taken into the field, where 5 feet or 10 feet contours are plotted and sketched direct, for a distance of 20 to 50 feet in elevation, up and down hill from the centre line, depending on evident requirements ; with a little practice, the distance to each contour can be taken and plotted very rapidly, obviating the necessity of notes. Intermediate irregularities, etc., can be also sketched in by eye, and the sheets when taken back to the office can be placed in proper alignment and chainage, and a tracing taken if necessary ; but probably the projected location 68 Railway Enginkkrinc. I *M' Vi line will be placed on these sheets and then trans- ferred to the field at once, or by another party following, or the whole matter may be held over until a decision is arrived at as to the correct location route to adopt; this will evidently vary with each case. If the contour notes are recorded in books in the field, they may be plotted on a continuous roll in the office ; but such a method is more tedious, and little irregularities which would be sketched . in the field are often omitted in notes. A topography party relieves the transitman of all note-taking except centre alignment, whereas all notes of natural and arti- ficial topography are taken by the transitman where no topography party is employed, thereby delaying the pro- gress of the whole survey. A topographer should prefer- ably be a Provincial Lantl Surveyor also, so that his work in recording land lines and making plans may at once be legalized. The qualificatif^ ind duties of the members of a sur- vey party are somew.iat as follows: The Chief of Party should be a man of vigorous mental and physical attainments, familiar with the details of survey life and minutiae, with a wide experience of construction, and even, if possible, of maintenance of rail- ways, well informed on such matters as have been touched on in previous chapters, and capable of commanding prompt obedience and zealous assistance on the part of every member of the party. If, in addition, a man can be found who has also a natural genius for railway location, he cannot be too highly treasured or paid. The chief of a survey party is the most important officer in the pay of a railway company where location is of a difficult and per- plexing nature. Crippled constitutions and receiverships are more often the result of poor location than from any other cause, hence the high value of the men who decide on such matters. A chief may be a strict disciplinarian and still command the regard of h'.s assistants; he should hsL\e free scope to dismiss anyone not competent and will- ing to do good work ; and should never do any work for subi>rdinates, except in the rarest instance, but should be well on at the front most of the time, devising the next step before it is needed, and having in view a general plan Railway ENdiNi'.KRiNti. 69 of the country, not lookinj^ straifjjht ahead, but feeling that just " beyond " there may be a better hne. The rate of progress is fixed by those at the front, the others must keep up. A chief of party carries usually a pocket note book, or even topography book, an aneroid barometer and a pocket compass. The Trnnsitmnn should be an engineer of some experierce, particularly in handling men, keeping full and accurate notes, and rapid and yet delicate handling of his transit. lie should be alive to the general movement of the men in his party, which means that he should not always be looking through his telescope at them, but com- manding their movements directly also, and above all, he should put his transit in position quickly, and not keep a whole party wailing while he dawdles over his levelling screws, etc. Where there is no topographer, the transit- man, in addition to keeping notes of the survey alignment, must sketch neatly, with necessary measurements, all buildings, roads, farm lines, etc., in fact all artificial and natural topography, and obtain all owners' and tenants' names. In a level country, topography should extend for at least 500 to 1,000 feet on each side of the line, as the location may be moved that much, and thereby run through houses and barns that have not been noted. This should be done where necessary by accurate chainage offsets. In country of steep side inclinations this is not necessary ; judgment will determine the width of the topography belt needed in each instance. The Leveller may be a young engineer of limited experience, although preferably one capable of rising rapidly to higher positions, and not one whose engineering horizon is bounded by such work. In addition to centre line levels, taken at each 100 feet station, hub, and inter- mediate change of vertical direction, the leveller notes the wooded and cleared portions, the class of timber, probable nature of material in cuttings and borrows ; the depth, volume of flow and high water mark of all streams, and establishes bench marks, at say each half mile on preli- minary SUrVv'^^'n. The Level .dman and Chainmen should not only be instructed how to do their work, but day after day should 70 Railway ICn(;inkkki\g. ' i he made to chain and hold their rods correctly ; chains should bo tested frequently. It is certain that tnore errors are due to poor chaining and roddins,', to insecure hul)S, and to slovenly work amongst subordinates generally, than to poor instrumental work, allhouf^h the blame for such errors is usually laid on the latter. A Front Picketmnn is invaluable and should be dis- tinct from the chainmen ; he should be an active, intelli// oi' f," ^ eauo/ Smo//a/)e/e ^AB'BC 'AC. obliterated and untracaable. There are three general m.tithods of prolonging a straight Hue beyond an obstacle. (a) By offsets, where the necessary offset is not very long ; this is the most accurate method. The measure- ments a^h^, «2^3» ^3^3' '^4^4 ^"^^ identical and made very carefully with a steel tape and plumb line ; the transit sites 74 Railway Engineering. would be at &•, n', b*, with a target placed on top of the obstacle, if possible, as a back sight check. (See fig. 19.) (b) By making a slight angular deflection measuring a certain distance until just opposite the obstacle, then deflecting back twice the first deflection, measuring an equal distance and then deflecting again on to tangent, by an angle equal in amount and direction to the first one, the error in chainage is usually disregarded ; this method introduces three angular measurements and is not likely to give an exactly straight line for this reason. (See fig. 19.) (c) B)' laying out an equilateral triangle, this fixes the chainage beyond the obstacle, and presumably the direc- tion and line ; but as this method introduces three angu- lar measurements and two linear ones, it is not apt to give as good results as the first two. (See fig. 19.) It is understood that if by placing a transit on top of a secure obstacle the line can be prolonged directly over it, it is best to do so even at considerable personal inconvenience. If very accurate transit work is desired, it is not best to tiust to the adjustment of the instrument, but take two points on each hub, and use the mean. In the same way, equal backsights and foresights in levelling should be ob- tained wherever possible, to minimize the result of a level being out of adjustment, and also it is best to adjust in- struments for about the distance ihat the ordinary sights are to be in any given class of country. The travel of the tube in a large change of focus often throws an instrument out of adjustment for very short or very long sights. It is ofJen found that a survey party, before being disbanded, has time to do cross-sectioning for construction ; this is a mistaken economy, and a source of errors and mutual accusations. The members of a survey party do not take interest in work they are not to superintend, and the cross-sections will probably be poorly chosen and exe- cuted. Then the centre line will very likely be altered in various places, which will invalidate all sections at those points. Generally speaking, it is best to have the engineer of construction do everything of an engineering nature which appertains directly to his work. Railway Engineering. 75 CHAPTER V. Roadbed Construction. ARTICLE 15. WATERWAYS. The construction engineer, after retracing the centre line, and checking levels, and establishing additional B. M.'s, if necessary, should verify and complete the list of structures fixed upon by the survey party. The class of structure will depend upon the money and material available, but its cross-section, if it is a water- way, will depend on the maximum flow of water it is ex- pected to carry, while if it is a cattle pass or public cross- ing, its minimum dimensions will be fixed by law. Many causes affect the maximum flow of water across a railway roadbed, at a given point, besides the drainage area ; in the case of si.iall streams or local watersheds, the building of the roadbed, and consequent roadbed and catch-water ditching, will concentrate the flow, from quite a large area, on a culvert that would naturally have had much less flow to accommodate ; this should be anticipated. Then, again, the construction of a railway in a new country will induce such activity as will causj large tracts of forests to be cleared off, and in a few years these cultivated areas will allow storm waters to pass off more rapidly than when the same area was in forest, which should therefore be antici- pated and provided for. If the drainage area is in a nearly level country, water will arrive at a given point more gradually than if the slope of the country is abrupt ; and also the shape of the drainage area and distribution of tributaries has a marked effect on the maximum flow. If a long stream has few and small branches, the maximum flow will be nmch less than though there were more and larger tributaries and less main stream, the total area being the same, especially if the branches empty just above the railway. Ii. this case the flood water fmm all of them 75 Railway Esois^i'^fi may arrive about the same fw»*, i^^my groHnitrAlso, sheds water much more rapidly t^** meMv/y Mi# lilphly ciTltivated grourKl. and small areas 4re mi/tt. liable to abnormal floods th«n large ones, because rloud bufvits seldom occupy large tracts of country. All such cons!derati^.' lJ..>///r, ' ^.J/ ^A//? x ' >'>V>'/'V^^.^ N ^"/»/on/( I ;, -VAVAV'M if^jtzi/af^iss.Tvr^T^i^^sgaesss^'jia^AiA'SiSis^^ -t'S n ./«»•> p* r,g2o 7>aeA /3ox, H -^ 2" "' r777r*i ' i ■^fTTT 1^3" • • _•■^ •_ _p_ • • • • • • ~ -'-t • • • * 1 O • •"" •~ • 9 • # • • m m . _ _ « • paving i Heoc/*ira// ^or /ran or Terra ^-T^^^.jwp -TTTTTTrrrTrrrTTTTr—.-^TryTrrrrrTrrrrmrr /of^p '/Ajc//no/ sSec//ort. ^//>e '/re/7cA z*'/'^'' conet-g'fp when the wooden ones are about decriyed, and in case this has been anticipated the wooden box culverts will have been made larger than necessaiy, sufficient to aliow of ™rii 8o Railway Engineering. 1 ;l^ this being done Cast iron pipes will be laid in the same manner as sewer pipes, except that the joints should in this case be caulked aud leaded as with water pipes, although sometimes this is omitted ; the cost per foot for cast iron and sewer pipes at the nearest railway depot to the structure will vary somewhat with the locality, but will be approximately as follows : TABLK XII. APPROXIMATE COST OF PIPES (noT INCLUDING LAYING.) Poiible Streneth ^ „, Sewer Pipe. Ciist-iron Pipe. Cost per foot. )laiiietet. 12-inch 35Cts. i8-inch 70 " 2 teet $1 30 3 feet 4 feet The difference $1 i5\ I go 3 00 4 80 8 00/ This does not include cost of hauling, laying, head walls or foundations. shown in the table, and laying of the of cost, as the less cost of handling sewer pipe and its absolute freedom from corrosion will always be greatly in favor of its adoption where well- burnt, salt-glazed, double-strength sewer pipes can be obtained within reasonable length of railroad and team- haul. Open Culverts. — Where a large flow of water is to be carried across a shallow bank some engineers use two or three lines of pipes, but the danger of this method lies in the possibility of debris collecting around the middle walls and gradually choking up the waterway. This can be guarded against by building a screen or paling some dis- tance above the entrance, which catches the debris. Gener- ally speaking, however, large streams and shallow banks demand open culverts. In many cases these may answer the double purpose of waterway and cattle guard, or waterway and cattle-pass, for giving passage for cattle under the track. Such structures may be of timber, stone, or concrete or brick walls, capped with stone; but whatever kind may be used, they should be decked with a complete trestle floor, such as to make them safe for derailed trains to pass over. And indeed, latterly, some roads are adopt- ing a solid timber floor, on which the ordinary road ballast is laid, or better still, a floor of discarded steel rails, laid longitudinally, filled in with concrete and covered with ballast ; in either case the roadbed is continuous, and free Railway Engineering. 8i from dan^^er by derailment or fire, and presents a nore elastic and uniform bearing for the track ties. On Plate II. (Figs. 23 and 24) are shown plans for a 6-foot open culvert of timber or stone. If the bank were deeper, the stone walls would need to be thicker, being designed as level retaining walls, and the timber culvert would need a more thorough system of interior strut ;, etc., for stability. If the embankment cross-section were to show a rapid descent just at the mouth of the culvert, it would be more economicc'il to place the stepped wings (Fig. 24) at right angles to the walls, in the form of iiead walls, about six feet from the centre line. This is not done, ordi- narily, because less economical, less stable, and subject to vibration and thrust from the train. The timber open culverts should be well drift-bolted in each course, and have the stringers also notched down slightly and drift bolted to the walls — the mud sills well sunk into the solid earth, and preferably with paving between them and a sheet piling apron at each end to prevent under-flow and undermining, as shown on Plate IV. (Fig. 28.) If the foundations are not good, a struc- ture, on piles, similar to the one shown on Plate III. (Fig» 25), will need to be used. The earth being retained by a layer of four inch to six inch cedar flatted on three sides, and the two walls held vertical by drift-bolting and notching down the stringers, or if necessary, by additional struts placed from top to top of piles as shown in the figure. The use of high framed timber openings on mud- sills, lagged behind with cedar like that in Fig. 25 is not advised, they are not stable and are liable to be under- mined. Wherever a depth sufficient for a cattle pass or farmers' undercrossing is required, it is better to put the structure on well driven piles extending up to grade, if a stone opening cannot be afforded. The valid objections to open culverts with vertical walls are : (a) That the structure being fixed in elevation, offers a rigid support to the track which, on banks, and on freshly made ones particularly, is elastic and settles down for several years, and rises and falls with the frost ; there- fore, at such structures there is more or less of a hump, and always a poor piece of track. 6 82 ■Railway Engineering. (b) That in case of the timber cu verts, the la^^ging behind the piles rots (juickly, and is rather awkward to replace. These considerations have led to the use, especially in the southern United States, of a form of structure shown on Plate III. (Fig. 26), which consists of two bents of piles. /^/ateH cross stettbn. SCal« Jin.^f/t 6' O/offn Ca/¥ert. T/rnhmn /«/»^/ /«'»«/ *tcft>»nrr/'ttv ^ /o/fpt-^tK^/ta/ tsectt'on. covered r^/^ /lar/np on '^^0 ^ />/o/7. ) » W^M*J >* tf '. O' S »:6'. on rnfaqa. r I I rnef e/e ifo/>oft. cross - Secfy'oo. Timjrf S' O/oer? Cu/rcr/r ^g^^- Wasonrf. -^^J Railway Enginlkring. Hi or two frame bents on pile foundations, with three 15 foot spans of trestle floor, having the two end supports made of mudsills resting well on to the hanks. It is probable that 45 feet of trestle floor is not appreciably more danger- ous than 15 feet of it, and the only valid objection to this form of structure is that the frost will heave the ends out of surface in climates like that of Canada or the northern United States, but its openness for repairs, the elasticity of the ends which rise and fall with the embankments, its freedom from rot, except the easily replaced mudsills, and the possibility of an enlarged waterway by rip-rapping the sloping banks, to allow for an exceptional flood, are all points much in favor of such a structure. This structure is evidently limited to banks less than eight feet high. The class of masonry for open culvert walls will need to be superior, owing to the effects of vibration from the trains, to avoid part of which oak planks should be placed under the ends of the stringers. The class usually specified is second-class bridge masonry, and will cost from $8 to $10 per cubic yard upward, depending on the quantities in each structu»a and total quantity in the contract. The economy of rubble concrete walls capped with a stone cop- ing is being now recognised. The cost of structures of these styles will be approxi- mately as given in Table XIII., taking masonry at $10 per cubic yard, including foundations ; paving at $3 per cubic yard ; sawn timber at $30 per M.B.M., in place including iron ; cedar lagging and timber walls at $25 per M.B.M. in place, and piling at 30 cents per lineal foot, driven, say, 10 feet into the ground. TABLE XIII. APPROXIMATE COST OF OPEN CULVERTS. Structure. Timber opening. Heii;ht of Waterway. 4 feet. 6 feet. $ 106 Clear H feet. $ iiC span in feet being 10 feet. 12 feet. $ $ 12G 135 15 feet. $ 148 Timber walls. 6 " 157 167 177 186 201 (Fig. 23.) 8 " 212 222 233 243 259 Timber opening, i piles and lagging. (Fig 25-) 1 4 feet. 6 " 8 " no 144 168 118 152 17G 125 158 183 133 1G7 191 145 179 203 Three span. Opening on piles. (Fig. 26.) 4 feet. G '• 8 " 170 203 208 251 256 267 Stone opening. Trestle floor. (Fig. 24.) 4 feet. 6 " 8 " 457 608 341 481 632 365 656 389 529 680 426 566 717 I ' * II ^ \r 1^. IMAGE EVALUATION TEST TARGET (MT-3) 1.0 1.1 ^ 122 12.2 ly B,. nil ui lift ^" iM 12.0 us |l-25 iU u& ^u^ FhotograiJiic Sdmces CGrpopaliQn ^ i 23 WBT MAIN STRCiT WI8SnR,N.Y. I4SM (716)a724S03 % \ 84 Railway Engineering. From which it is evident that piles with lagging is slightly the cheapest, except with the smallest height and span, and that at 8 feet high and 15 feet span the three- span opening comes to about the same as the other timber structures. The cost of the stone opening is Irom two to three times as great as the timber ones in first cost, at $10 per cubic yard, but in many cases this could be materially reduced by using concrete at $6 to $8 per cubic yard, at which price a very superior quality can be made even in small quantities. An interesting feature of this table is the deduction that the length of span affects the cost so slightly, it will hardly pay to risk anything in size of water- way for such trifling economies. ARTICLE 17. — SMALL WATERWAYS WITH HEAVY EMBANKMENTS. Under these conditions pipes may still be used, if care is taken in laying them ; up to any height, if the. waterway is very small ; but for cross-section areas of four square feet to twenty square feet, the structure com- monly used is the box culvert, which may be made of timber, stone, concrete or brick. The two latter, however, being used, usually, in the arch form, as otherwise stone covers are necessary. Timber Box Culverts. — These are used where cheap structures are desired, or often in undeveloped districts where construction is hurried, timber plentiful, and stone scarce, they should not be put under embankments more than 12 feet to 15 feet high, unless built large enough to admit iron pipes that will carry the rainfall after the timber culvert has begun to decay, which will be in six to twelve years, depending on the timber, etc. If the bank is a shallow one, it will not be very expensive to replace the decayed timber culvert by another similar one, or by a stone box culvert, at a time when stone can be cheaply delivered by rail and the company can afford the outlay, and if the covers are made long, as in Plate IV. (Fig. 27), they will hold up for a year or so after the side timbers have started to rot. Of the two styles shown, the one (Fig. 28) is superior in some respects. It is fastened by iron drift bolts, instead of oak tree nails. It has a row of sheet piling driven at the ends to prevent underflow and Railway Enginekring. 85 undermining, and has solid paving laid between the mud- sills, all of which are distinct improvements. For such structures, probably, cedar is the most durable wood, and pine next. A distinct advantage of timber box culverts is that on soft swampy foundations, all that is necessary Plate m settle I in. *» fyf /6'/='//e Cu/vert cross ■ sec/f'on holf s/' ^ongifut/f'ntt/ ■Sect/oft. P/an (vtithoyf covar^) Railway Enginebking. 89 how steep — in order to get the outlet low enough to pre- vent undermining, the direction of the discharging stream, in plan, is immaterial — water will get away somehow, but, in profile, there should never be an increase in the rate of fall, just below the lower end, unless on solid rock. If the foundation bed is solid, the core which holds up the pav- ing may be left of correct height to carry it, but if the foundation is poor, it will be best to build first a layer of concrete one foot to two feet thick, and commence masonry work and paving on this, or, in case the foundation is always to be under water, a grillage (platform) of timber will be suitable, as in timber box culverts. . Weak foundations are often the cause of failure in stone culverts, and all doubtful ones should be tested by the engineer himself, by driving an iron bar down in sev- eral places, and it is best to be on the safe side ; a little sediment on the paving will do no harm, and will be swept out at each storm, whereas if the discharge end is too high, first a hole is worn, and finally the lower end is undermined and falls down. If possible, culverts should be located at right angles to the centre line, and this can usually be done by divert- ing the entering stream, and using the material in the embankment adjacent. Skewed structures are expensive in many ways, more particularly, however, with arched culverts. The inspection of stone culverts during con- struction should be a rigid one, as rascally work can be hidden quicker in this class of masonry than in any other. Especially inspect the covers as to soundness and proper bearing on the walls, which should be from 9 inches on small culverts to 15 inches for large ones ; they should have full bearings at each end, and be well spauled and mortared at the joints, to keep out earth and water. In bringing embankments against all culverts, care must be taken not to shove them over; filling should, if possible, be carried on on both sides at the same time, but if not, then earth should be shovelled over, up to the level of the top of the covers, before a high bank is brought forward. These remarks apply more particularly to arched culverts. The use of solid concrete box culverts to take the place of masonry ones is on the increase. They can be built cheaper, and when a knowledge of the science of cements 90 Railway Engineering. ii «v* and proper concrete making is more general, such con- struction will be largely adopted. Specification for Stone Box Culverts laid in mortar. — •' Culvert masonry shall be built of good, sound, large, flat-bedded stones, laid on their natural and horizontal beds. The stones used must not be- less than three feet in Plate YI scale titffft. -' •; 1 V.I r' _.i._' J 3*4' Masont/ Sox Cu/\f*rt ^m'mfM'm'mmi. ? niK 31 r/g<52. taction /o: eT /aifgifiidttta/ sectr'on \ I t . il' ^ •>■ ■.«:o"> 1 i-S- ^ '5! rt-i- ^ — v-pTT /o;or A p/e/to/founc/mtfon. 2'»3' Dry Masonry Box Cufvert area of bed, nor less than eight inches thick, and must be hammer-dressed so as to give good beds with half-inch joints or less. Headers shall be built in the wall from front to back, alternately, at least one in every five feet of wall and frequently in the rise of the wall. The least width of bed for stretchers shall be twelve inches. In Railway Engineering. 91 larger structures, all stones must be heavier in proportion, every attention must be paid to produce good bond, and to give the whole a strong, neat, workmanlike finish. All dimensions must be according to plans, but these may by varied if the engineer so requires." *• The paving shall be of stone set on edge, twelve inches deep, packed solid, of an even face, and inclined in direction of the stream." " The mortar shall consist of one part good quality Portland cement to three parts of clean sharp sand, and all joints, beds and interstices shall be carefully filled with mortar and packed solid — the exterior faces and interior of barrel shall have all joints raked and pointed with mortar, consisting of one part cement to one part sand." Crst of Box Culverts. — Taking timber in place, includ- ing iron and foundations at $25 per M.B.M., culvert masonry at $6 per cubic yard, and paving at $3 per cubic yard, including foundations. The cost of box cul- verts according to figures (28) timber, and (29) masonry, are given in table XIV. TABLE XIV. APPROXIMATE COST OF BOX CULVERTS (l6 FOOT EMBANKMENTS). Total cost for depth of top of paving Waterway. below subgrade. 1 Structure. 10 it. 20 ft. »oft. — \ 40 ft. 50 ft. 60 ft. $ $ $ $ $ $ Timber Box.... .. 2'X3' high 183 306 429 552 675 798 Fig, 28. 3'X3' II 213 356 500 643 787 931 •1 3'X4' II 234 397 560 723 886 1,049 II 4'X4' II 263 446 ' 629 812 995 I. 178 " 4'X5' 11 281 483 686 888 1,091 1,294 Stone Box . . . .. 2'X3' i 1 254 420 587 754 920 1,086 Fig. 29. 3'X3' • 1 267 444 620 79'/ 974 1. 151 1 « 3'x4' II 364 607 851 1.094 1.338 1,582 II 4'X4' II 3S5 645 905 1,165 1.425 1.685 , 4'X5' II 501 848 I .195 1,542 1,889 2,236 From which table it is evident that the stone culverts increase in cost much more rapidly than the timber ones, owing to the necessary increase in the thickness of the stone walls, being estimated at 2 feet, 2| feet and 3 feet thick for culverts 5 feet, 4 feet and 5 feet high (in the clear) respectively. It does not' pay, evidently, to build small timber culverts, other things being equal. 9a Railway Encinekking. ARTICLE iN. — LARGER WATERWAYS WITH HEAVY EMBANKMENTS. When a single box culvert 4 by 5 feet in cross section or, with very long covers and corbels, possibly 5 by 5 feet, will not carry the maximum flow of a s.tream, we must either use double or treble box culverts or an arch culvert. The intermediate walls of double box culverts may be made pointed to divide the flow of water, and a screen or paling may be erected some distance up stream to catch driftwood, but, even at best, their use is doubtful for the same reason as with double lines of culvert pipes, i.e, the danger of logs, etc., choking up the entrance ;. whether an arch culvert of equivalent area will be cheaper than such a structure will depend on the availability of brick, cement or cheaply-cut stone for arch sheeting on the one hand, or of large-sized stones for covers on the other. ARTICLE 19. — ARCH CULVERTS. The selection of materials for the construction of arch culverts will depend on circumstances ; where good weathering stone can be easily quarried and cut in the vicinity it will be usually used, but if stone is scarce or costly, and well-burnt brick plentiful, then brick may be found cheaper ; of course brick so soft as to be unable to stand erosion or frost should never be used on exterior faces or for the arch sheeting. The use of concrete for arch culverts is yet a very occasional one in America, but is likely to steadily increase as we have more skilled civil engineers who are familiar with the production of a cheap concrete with superior exterior finish, capable of standing frost and erosion and certain to remain sound for an indef- inite number of years, which necessitates using absolutely sound, high-grade cements, and until an engineer has the opportunity of making certain of his cement by system- atic testing, he is advised to avoid the use of any but the very smallest monolithic arch culverts, although, of course, their construction presents no structural difficulties, beyond the precaution of defining occasional lines of separation in the arch sheeting so as to avoid irregular contraction lines. Railway ENciiNEERiNo. 93 Plate W ecalt 1 in • eft ^ fro/rfjr/e nation. '^SecT/o/t. Longitue//na/ Secfwn. ^/^. SS. 6'Sfo/?e Arch. /f.O" /^/g. S^. 8 ' Sto/?e Arch. 94 Railway Engineering. Plate WI fyg,65 /6'6tof?e . Arch Cu/vert i Cross St cf/o/1. i,/^rontytf^£U>fof/on. Ce/f^« Lon^iAte/ina/ Secf/on centre s i P/an. The chief features of arch culvert designing are : — (a)^The shape of the end walls. (6) The depth, class and form of the arch sheeting. (c) The dimensions of the arch abutments. Railway ENciiNKBKiNC. 95 (a) The shape of the end walls will depend on the span of the arch and its rise. For small semicircular arch culverts, say from 5 to 8 feet span, the retaining head-wall shown, Plate X., I'ig. 39, and Plate VII., Pig. 33, is generally used ; for segmental arches of somewhat longer span the same may be advan- tageous, but as soon as a larger retaining wall becomes necessary its use should be abandoned in favor of stepped wings; the reason for this is that a surcharged .etaining wall, with nothing but mortar to bond it to the back of the ring stones and often loaded with wet, slippery clay filling, is liable to be displaced, unless made very heavy, and thus the designs, as shown, Plate VII., Fig. 34, and Plate VIII., Fig. 35, of the types shown on Plate X., are found more suitable. The choice between straight wings and flaring ones, or between wings flush with the faces of the barrel of the arch, and those set back clear of the ring stones will depend much on the taste of the designer ; for small spans liable to catch driftwood the choice should rest on flush wings, with some flare to avoid contraction, but with larger spans, of say 15 feet or over, a wing set back so as to show the arch ring stones will have a better appearance, and give equally good or better bond between the wing and the abutment or parapet wall. The small parapet wall of a culvert with stepped wings is well but- tressed and very stable ; the wings themselves usually have a face batter of i in 12 to i in 24, and a section at any point suitable for a level retaining wall (i. e.) about ,^ height 4- batter, their length will be economically curtailed at a pjint where the steps are 2 feet or -^^ feet above the ground level. Stepped wings are preferaL e to those with inclined copings, as the latter are liable to become dislodged in time, and do not give an easy means of climbing the bank, and, also, the coping of a parapet wall of a brick arch culvert should preferably be a stone one, as bricks are liable to be displaced by ties, boulders, etc., rolling down the bank. (b) The form of the arch will depend on the depth of bank ; wherever headroom permits, a semi-circular arch is used, partly because the arch sheeting, stones are less expensive than those for any other than segmental arches. 96 Railway Engineering. being all cut from one template, and partly because the abutments need not be so heavy ; but as the quantity of cut arch sheeting is greatest in a semi-circular arch the saving Is not very great on the structure as a whole, but when the depth of bank is the limiting feature, a much greater waterway can be obtained by the use of arches of Plate IX '. ffnf t/trm/itt /7^. 36 6*gm»nfa/ /ircfi. fiS-ST Semi £://ifitical /frch small rise to span, elliptical, segmental, or basket-handled, at a slight increase in cost. In small arches, it is cheaper to use roughly cut or even rubble arch sheeting of a greater depth, than to build one of first-class cut stone of less depth ; but as the span increases, the economy of .' ■ ivi'ii^j B aji' ' Railway Engineering. 97 carefully cut and bedded arch sheeting will point to the use of the minimum depth. The workmansh'p on stone arch sheeting should be of the quality figured on, and if cut stone is called for, it should be as shown in the upper diagram of Fig. 40, because if left narrow at the back, (he mortar that fills up the discrepancy being weaker and PluU X /70^. Cani>-at far i/ar ArcM»t. ng.4i Ctnf>tt ■ftr ii £//tAri€^ ArcA more compressible than the stone tends to throw exces- sive loads on the inner faces of the stones , this is point over which too great an amount of inspection can hardly be given, especially if the stones a;'e of minimum depth. When deep rubble arch sheeting is used, the mortar will be strong enough to stand the pressures allowed. 7 98 Railway Enginekring. If arch sheeting is of brick a greater depth must be allowed usually than for stone, unless the brick is of very good quality and well bonded, and as bricks are not usually made bevelled unless for a very large contract, and are all of a uniform size, the bonding of the several rings of brick in arch sheeting of several bricks in depth is not possible except at arbitrary intervals, depending on the curvature, when the outer ring is one brirk thickness behind the ring inside it, at which point a header is in- serted; for a circular arch this is about once every 33*^ of arc and is independent of the span. Longitudinally both brick and stone arch sheeting should be well bonded also, and after the arch has been completed and the centres removed, a heavy coat of cement mortar (i to i) should be plastered over the back of the arch down over the haunches or spandrel filling so as to prevent percolation through the joints. In construction of the arch and span- drel masonry the two sides should be carried up at about equal rates, as a heavier load on one side will tend to push over the timber centres. (c) Arch abutments need not be made of such an expen- sive class of masonry as that of the arch sheeting. A rock- faced ashlar about equal to second-class bridge masonry is suitable, and in designing their dimensions due regard must be had to the character of the filling behind the abutments and the depth of filling over the crown. There cannot besaid to beany fixed law by which the dimensions can be determined. The various theories advanced disagree in vital points. Some take account of the horizontal thrusts tending to increase the stability of the abutments, and some do not ; some attempt to allow for roll- ing loads, and others use only a uniform quiescent load. It nay be said in g^\ /to' TTT III \ III I' >!' ii! II II II I] ii| lilt l|il ill! [Ill 11 1| iS ii t P/ar?. I02 Railway Engineering. be carefully laid with a thoroughly good bond lengthwise of the arch. The face ring stones shall be left rough on the face, except a i^ inch intrados draft, and no projection allowed of more than 3 inches from such draft. The spandrel filling shall be rough rubble similar to good box culvert masonry, but of pood "bed, bond and quality of stone. The abutments, wings or head walls, and parapet walls shall be either first-class or second-class bridge masonry as the engineer may direct. (See bridge masonry specifications. The cost of arch culvert masonry will vary with the price of stone cutting, price of brick and labor, but may be taken ordinarily at $6 per cubic yard for rubble arches ; $8 to $10 for second-class arch abutments ; $10 to $14 for cut arch sheeting ; $8 per cubic yard for ordinary brick arches. The quantity of masonry in arches of even the same span and rise will be so entirely dependent on the height of ab«rtments and depth of foundations that no table will be given. The tables given for purposes of approximate esti- mates in Trautwine " Engineer's Pocket Book," will be found very usef\il. ' ARTICLE 20. ARCHES. So much h^s been written on this subject and the design of large arches for rivers or roadways, or for carrying roads over railways, etc., has received such elaborate study, that it is outside the range of this work, but types ot such structures are given on Plate XI., and many of the remarks on arch culverts will apply to the larger structures with even greater emphasis, (e.g.), the importance of immovable foundations, and taking care of the line of pressures below the haunch and in the abut- ments, for this purpose the abutments are often built with the beds inclined to the horizontal and nearly at right angles to the pressure, see Fig. 36, and in any case should never be further from such a right angle than the angle of friction of stone on mortar. Whether in a given case an arch or two abutments and a plate girder span will be preferable, depends on the depth of the bank and width of stream, as far as economy Railway Engineering. 103 is concerned, but other considerations are the greater dura- bility and safety of an arch, its finer appearance and an absence of repairs. The use of concrete with steel rods or wire embedded in the tension side of the arch sheeting has lately come into use for arches of small rise, especially where rolling loads tend to distort the arch, the possibility of this form of construction lies in the fact that steel and concrete have almost identical co-efHcients of expansion. ARTICLE 21. — BRIDGE SUBSTRUCTURES. As the size of waterway increases, the cost of an arch soon becomes excessive, owing to the heavy abutments necessary for arches of long span and small height. On the other hand the cost of bridge abutments increases very rapidly with the depth of bank, so that we have two limiting features to guide us in the selection of the style of structure most suitable for a given small stream or creek, e.g., with a 30-foot span and embankment 30 feet hig) the costs about equal each other. But whenever the arch does not cost appreciably more than the open span it should be selected, owing to the absence of floor repairs and to increased safety given. It must be remembered that the addition of a solid buckleplate floor and ballast to a plate girder will, however, make it practii:ally safe and almost eliminate repairs. When the stream to be crossed is of considerable magnitude the question of span lengths will be the first one to decide upon, which must be done with due regard to the probable life of iron work and the cost of replacing and painting it, as well as to the total present minimum cost of structure. The approximate minimum cost of structure is ob- tained when the cost of the trusses, not including the floor system, is equal to the cost of the masonry, which should include the cost of foundations, etc., but exclude the cost of those portions of abutments of which the function is to retaiu the earthwork and not to support the bridge, i.e., the wings, etc. ; but it is usually safe to arrange the spans so that the masonry will cost slightly less than the iron, because the estimate of the latter can be made quite accurately, whereas ■ able. These conditions are, that it is to carry a deck truss, and that the stem of the abutment is stepped into an ascending hillside, thereby lessening the quantity of masonry in it considerably. See Plate XII, Fig. 46. Essential advantages of this abutment are that it is prac- tically in stable equilibrium from earth thrusts as the earth slopes run around the stem, and that water cannot lodge behind it. For through trusses needing wide piers, a *'T" abutment is not especially economical, unless the Railway Enginebring. 105 saving on the hillside steps is considerable. The masonry for the pier should be first or second-class bridge masonry, but the interior of the stem may be of heavy rubble, with a cut facing, thus reducing the cost of the abutment to an average price of $8 to $10 per cubic yard. The " U " abutment is similar to a " T," except that the stem is split into two parts and separated until con- siderable filling can be placed between the two parts. For deck spans up to 25 feet in height and through spans up to about 30 feet in height, the masonry in this abut- ment is less than in a " T " abutment, but above this height the quantities increase very rapi lly owing to the increased lateral dimensi. .s of the wings, which are designed as level retaining walls. The class of masonry necessary, however, is superior in the wings to that of the masonry in the stem of the ««T" abutment, and the average cost of masonry will range from $1 to $2 per cubic yard more, or, say, $9 to $12 per cubic yard, so that it is very seldom less expensive to build than the "T" abutment, but it is very much used, owing to an impression that the wmgs are not affected by the train vibration. It must be kept well back from a scouring stream, and the toe of the slope in both of these classes of abutments should be protected by rip-rap, if there is any running water. Another serious objection to a *' U " abutment is that it is liable to lodge water between the wings. This should always be provided for by weep holes. Whether this abutment is cheaper than a wing abutment will depend on the allowable slope of the earth, and also ou the economy that can be effected by stepping the wings into the hillside, see Fig. 48. Some engineers economize masonry in the stems of '* T " and wings of '• U " abutments by introducing semi-circular arches of 10 ft. to 20 ft. span, just back of the pier-portion of the abutments The wing abutment is usually used where the ground is level behind the abutment, and where the face is close to running water liable to scour, in which case the wmgs are flared back about 30° so as to prevent any contraction of the waterway. This abutment presents a neat appearance, and the backing may be made of rubble masonry, thus reducing the cost of the whole to about the price of "T" 8 i »; 1 i 1 06 Railway Enginbbring. abutment masonry, i.e., $8 to $10 per cubic yard, but it has several objectionable features : if the foundation below footings is deep, to good bottom, the quantity of masonry in the foundation is excessive. See table XV. (C). And _-^< 'Torver" "7" 't/' 'Cofniinat'»n' 'fy/^gi ...... r.- Bric/^e Ahutmenf Tyfies. ^^.^^y ?l, ,1 4**M^i(—' ' ' ' ^ I . c c ^ I t: -in -Tvrr 9... -*i fo-r: ^ Front £/tra/)cn -^ Back £U^otton. c A»'-»A»* r j:>»' D / •s.»' "3T= !^ .(x- ,lf isf^' / / ?- :/■ I » r— -V^r;» ^ii'ci'i;'* »>^ VAhutment It."*. . ■ ■ij .'■■■<■ t- iJ/i/*? £i/eifo//on. Railway Enginkering. 107 also, its design as a level retaining wall is always a ques- tion of more or less doubt. The ordinary rule of the width at base, being ^ of the height -f* ^'^^ '^i'""^ batter, is satis- factory if the filling behind is of average quality, but if made of heavy wet slippery clay, the structure may be in danger. Again, in designing the foundation it is necessary to know that it will always receive support in front or else the rule of -,^ must be carried down to the foundation bed. For these reasons, an abutment with a straight back and only a tapering to the wings is preferable to one with wings flared back, as it does not hold water behind it so readily and is not under so severe a strain tending to crack the wings from the body of the abutment. To increase the stability of a wing abutment the foundation pit in front should be always rammed solid with clay, or preferably concrete, up to the ground level, and in cold climates a frost batter given to the back of the parapet wall. See Fig. 45. This prevents the frost from dis- lodging it. There is a great diversity of opinion regarding the cor- rect cross-section of retaining walls in general, and in applying any rule or formula the utmost caution is neces- sary, because each design is a problem in itself ; items to be considered are : the material to be used for backing, the manner of placing it, the slope of the natural ground behind and in front of the abutment, the drainage of the area behind the abutment, the kind of masonry and mortar to be used, etc. So many complexities would thus be given to any theoretical formula that in such designs it is, in most cases, best to be guided by past successes and failures in structures that have been similarly situated. The actual design of an abutment is very simple, the depth from base of rail to bridge seat, and the length of truss will be given, and also the distance apart of the trusses, centre to centre. Thus, deck trusses will need a bridge seat about 16 ftet long and 3^ to 4^ feet wide, while through spans require bridge seats 22 to 25 feet long and 4 to 5 feet deep. The approximate quantities of masonry for different styles of abutments as given in table XV. and plotted in diagrams, will be understood as extending to a uniform foundation level, the quantity saved in " T " and •• U " abutments by stepping into the hillside must be '■^ B loH Haiiavay Knginkrking. deducted, and the quantity in foundation courses added, both of which will he so much less favorable for wing abutments in any comparison involving deep foundationn or steep hillsides. TABLE XV. Approximate Quantitiks op Masonry in Abutmrnts. (A) FOR DKCK PLATE GIKDBK SPANS, BRIDGE SEATS l6 KEST WIDE, CAL> CULATEI) FROM DESIGNS GIVEN IN FIGS. 44, 46, 48. Not including footing coursts. Style of abiitmenl. Depth from bate of rail to top of footlnitt, 10' m' ao' 3j' 30' 3}' 40' c. yds. c, ydi. c, ycli. c. yd*, c. yds, c. yds. c. yd*. Sirnlghi winK abuiinent 38 Ho iji aj; 40a 396 841 "T" abutment, earth slopes, it to I... 4} lao 327 366 338 74a 979 "T" " " " I to I... 37 77 ijo 344 361 500 66t "U litoi... 43 loi aio 358 58a 858 i,i9j "U" " " " I to I... 31 71 144 343 391 375 800 Tower " thickness 30 per cent. of height 37 49 79 119 166 aaa 383 ! ti (B.) FOR THROOGH SPANS, BRIDGE SEATS 22 FEET WIDE, CALCULATED FROM baker's "MASONRY CONSTRUCTION." Not including footing courses. Depth from base of rail to top of footinxa. Style of abutment. 10' 15' 30' 35 30' 35' 40' c. yds. cyds. c. yds. c. yds. c. yds. c. yds. c yds. Wing abutment 44 104 186 394 426 388 781 "T" abutment, earihslopes, iji toi 78 169 309 481 696 ••T" " ■' I to I 56 120 ai9 346 494 676 879 "U" " " ijitoi 47 107 306 386 650 '• U " " " I to I 36 80 149 371 453 713 1,033 (C.) AREA OF FIRST FOOTING COURSE FOR FOUNDATIONS OF ABUTMENTS AS ABC.-" 'N SECTION (A.), ALLOWING 6* PROJECTION ALL AROUND. Depth from base of rail to top of footings. , -. , Style of abutment. 10' 15' so' 35' 30' 35' 40' sq. ft. sq. ft. sq. it. sq. ft. sq. ft. sq. ft. sq. ft. Straight AVing Abutment 265 384 569 797 1,047 '.33° 1.673 " T " abutment slopes i| to 1 303 399 400 499 599 700 801 "T" " " I to 1 14a ao9 280 349 419 489 359 "U" " " i| to 1 193 311 477 670 917 1,076 1,330 "U" " " I lot 139 313 333 458 614 734 806 Tower " 114 Ug «96 243 29° 337 384 Railway ENciNiiKRiNo. IO ^ ' ui t»>wi. Railway Engineering. "3 in which case similar tests would determine what the necessary length of base should be. (3) Cutwater designs: — Wherever there is any appreci- able current in a river, it is necessary to construct the up-stream end of the pier of such a form that it will divide masses of driftwood, ice, logs, etc., as well as the current itself. Probably the simplest form is that shown in Fig. 52, which will not cost appreciably more to construct than a square pier, as the nose is a right angle and the faces of ordinary quarry-faced ashlar, but such a form is suitable only for streams carrying light ice or moderate jams of logs; in place of this the more ornamental forms shown in Figs. 51 and 53 would be equally satisfactory, especially the latter, but cost considerably more, and should therefore be used only on very important structures. Where piers are to be placed in swift currents, or in any stream carrying heavy jams of logs, or thick floes of ice, their cutwaters should be of designs similar co Figs. 49 or 50. The cutwater of the former hardly extends high enough and is not flat enough for Canadian rivers, and besides it lacks the valuable addition of a small pointed lower end, which is introduced to eliminate an eddy at that point in swift currents, which tends to undermine the end of the pier, unless on solid rock. Probably the St. Croix pier and cutwater are suitable for the conditions they were designed for, but the intention of the design on Fig. 50 is that the jams will rise on the nose and split in two, passing on harmlessly. Stone masonry bridge «piers will cost from $9 to $15 per cubic yard, depending on their height, size and tiie cost of quarrying, transporting and cutting suitable stone. If expensive cutwaters are needed this will add to the cost ; those used under severe conditions being of a first- class cut stone construction of large dimensions, clamped together and dowelled also, with a strip of boiler plate added to the nose to prevent dislodgement of stones. The following specification of first-class bridge masonry will apply to both abutment and pier construction, but in many cases a less severe specification has resulted in satisfactory and durable work. 114 Railway Engineering. ; Specification for First-Class Bridge Masonry. — " This class of masonry will be ranged rockwork of the best description, from stone of approved weathering quali- ties, and will be laid in suitable cement mortar (i to 2 natural, or i to 3 Portland). The face stones will be accurately squared, jointed and bedded, and laid in courses not less than 12 inches thick, decreasing in thick- ness from bottom to top of walls ; the joints and beds to be less than half-inch and joints well broken, no break to be less than nine inches. The stretchers to average at least 3^ feet in length with 3 feet as a minimum, to have at least 16 inches bed, and always at least as much bed as rise. The headers to have a width of not less than 18 inches, and to hold the size back into the heart of the wall that they show on the face ; they shall occupy at least one-fifth of the area of the face of the wall, and be practically evenly distributed over it, so that the headers in each course shall divide equally or nearly so, the spaces between the headers in the next course below. When the walls are not more than 3J feet thick, the headers shall run entirely through, and when between 3^ and 6 feet thick, there shall be as many headers of the same size in the rear as the front of the wall, and the front and rear headers must alternate and interlock at least 12 inches with each other. In walls over 6 feet thick, the headers shall be at least 3^ feet long, alternating front and back as just described, their binding effect being carried through the wall by inter- mediate headers of a similar character. The stretchers in the rear of the wall, and the stones in the heart of the wall shall be of the same general dimensions and propor- tions as the face stones with equally good bed and bond, but with less attention to vertical joints, and must be well fitted to their places, and carry the course evenly quite through the wall ; a header shall in no case have a joint directly above or below it, but rest entirely on a stretcher at the face ; any small interstices that may remain in the heart of the wall shall be carefully filled «vith mortar and spauls. The face stones shall be left rough on the face, with no projection of more than three inches from pitch lines, and two-inch drafts will, in general, be carried up and around all projecting angles. Railway Engineering. "5 In the construction of piers, it is understood that the description above given for face work shall apply to both ends and both sides of the pier. Copings are to be cut and dowelhed or clamped according to coping plans fur- nished, the top shall be crandalled and pean- hammered, or otherwise brought to a smooth surface, and so arranged as to bring the pedestal plates of the trusses exactly on the centre of especially large coping stones of dimensions given on the plans." ARTICLE 24. — METAL OR METAL AND CONCRETE PIERS. On Plate XV. are shown several applications of meta and concrete for bridge piers. The method by screw piles founded in mud is quite unique, and has not been attempted in America for railway bridge pierSj but the sttel cylinders filled with concrete and founded either in mud on piles or anchored to the rock by iron dowels are more familiar. For light highway bridges this method is quite suitable, but it is probable thai, except in the form of one large cylinder, as a cofferdam to a pneumatic cais- son, both filled with concrete and sunk in waters not needing cutwaters, their use for railway bridge piers will be exceptional, as the more massive forms shown on Plate XIV. will be better able to withstand the vibrations of trains and impacts of ice, etc. ARTICLE 25. — IRON VIADUCTS OR TRESTLES. The features usually under the control of the railway engineer are the general lay-out, the design and construc- tion of masonry, and the erection of iron work ; the detail designing of the iron being essentially a branch of bridge- work. [a) General lay-out. — This has resolved itself in America to be, in general, a systern of braced independent towers and suspended spans (see Fig. 54) ; the towers are usually about 30 feet spans, with posts vertical in side elevation ; and, in end elevation, the girders are spaced 8 to 10 fe«^t centres, and the posts battered at 2 to 3 mches per foot, depending on the allowance for wind, the aim being to avoid tension in the windward pedestals at the most unfavorable instant. The suspended spans are usually also plate girders of 30 feet to 60 feet span, depending on i ii6 Railway Engineering. the height, the greatest economy being claimed when the cost of girders and longitudinal bracing is equal to the cost of towers and pedestal masonry. The usual design - ««■•«•/■ «iM/«« 9^^i*^. PlattXV Afeto/ofTt/ tt»tvtt»n /6.<»/« Siriita Brtt/gs P/er ^ 9/eit>T/en -^ Secf/an, ■SunZ/Ay Ojf»n effmt/g/ffg «tt/C0/n/bretM^ffsn SMCf/inkm ^>/«r. Railway Engineering. 117 is with diagonal rods acting in tension and the girders resting on top of the posts, with slotted holes for expan- sion, but some late designs are for rigid, riveted bracing and posts extending to the tops of the girders, 'which are riveted to the webs of the posts, temperature changes being taken up in expansion pockets 'jvery 100 to 200 feet. This system is theoretically more rigid, but costs more and demands a perfect system of pedestals, any settlement being dangerous to a proper distribution of stress. In estimating the weight of iron for approximate work, the following rule may be useful : The weight of metal in the towers and bracings, in pounds, is equal to about 8^ times the longitudinal section area in square feet of the ravine below the line of girders and between the faces of abutments ; this is based on a loo-ton consolidation engine and a high viaduct, say 100 feet, this will be changed to say 9^ times for a viaduct 50 feet high, and io| for a viaduct 35 feet high with the same weight of engine. The weight of girders, in pounds, may be estimated at (9/ + 100) pounds per foot run of a span, where / = length of span. The price of iron varies con- siderably, with cost of erecting falsework, if any, and cost of erection and freight in general, but is about four cents per pound, in place, as a minimum. The floors of viaducts usually consist of say 8-inch by lo-inch oak ties about 12 feet long on their edge, boxed one-inch over the girders, and fastened to them by hooked bolts which pass through the guard rails and hook under the upper girder flanges ; the spacing should be not more than six inches clear, and guard rails either double or with an inner guard rail of ordinary flanged rail. Some recent designs, how- ever, call for solid floors of steel troughs filled with bal- last and with ordinary track ties, which, certainly, would lessen vibration and increase safety in case of slight derailments. (6) Pedestal Masonry. — The greatest care must be exercised in laying out and building the abutments and pedestals, as any error in position or appreciable one in height is very serious, because the iron work, being manu- factured at a distance contemporaneously with the masonry, is shipped to the spot partially assembled, and cannot be afterwards altered except by a slight shimming ii8 Railway Engineering. \t up of pedestals built too low. The shoes of the columns are always bolted down to the copings, and in high struc- tures these bults should be built into the pedestals 5 or 6 feet, by passing through the stones as they are laid in place (see Fig. 54), the bolt holes are afterwards fill* d tight with sulphur, lead, or neat cement grout, while if the structure is not very high or subject to heavy winds, the anchor bolts are only sunk into the coping stones, dove- tailed by wedges and cemented as before. Pedestal masonry is sometimes built of well burnt brick covered by a stone coping, and the use of monolithic concrete is especially adapted to this class of work, as it permits of the anchor bolts being buried in the concrete to any depth during construction. In any case the best class of work must be done, as the strains and thrusts acting are of higher intensity than in ordinary masonry, and the pedestal is not only under considerable vibration for so small a mass, but may be put in tension on the windward side of high structures. The cost of stone pedestal masonry will vary with the conveniences for handHng small quantities of large stones at each spot, and with the amount of cuttmg required, from $10 to $15 per cubic yard, whereas a very high class of concrete may be done for at the most $8 per yard as there is nothing to move from place to place but the plank moulds and mortar box. The coping of concrete pedestals should be made very strong, say, i cement, i^ sand, 3 stone, with a layer of i to I mortar for i^ or 2 inches thick on the top and sides, put on at the same time as the rest is being built, and incorporated with it by vigorous trowelling and ram- ming, etc. ARTICLE 26. — WOODEN TRESTLES. In America where timber is plentiful, cheap and widely distributed, where capital is often limited and con- struction hurried, and in inaccessible regions, the use of wooden trestles has been of great economic value. It is yet a factor not to despised ; and although their design is apparently not very difficult, yet it should be thoroughly understood by the young railway engineer in its many phases at an early date in his practice. We have prob- ably 100 feet per mile of railway in Canada, or about 300 Railway Enginekring. 119 miles altogether, and we may safely figure on a continual renewal of at least half of this every seven or eight years, which represents an annual drain on our forests for this purposeof perhaps 40,000,000 F.B M., while the other half Plate XVI alcf» 9/»tf»fi»n erott-ttefi'ort. "/jp S4: iron Tr^^tU «r Vfacfuct Ouff/'/res. *€•/• f 'ta/f: tmtf PUu XVII D • 9 Xi (It 7wn»lt % (it ami/eff'^n^'Mii^ '.:3 mmnlf- Raiiavay Enginrkking. 123 :, I (c) Trestle Bents and Systems. — The ordinary styles of bents are with four posts, which are increased to six posts it) very hif,'h trestles, each story or deck being braced by one or twi> pairs of cross or sway braces — the plumb posts being five feet apart, and butter posts sloping at from two to three inches per foot. The longitudinal braces consist of diagonal braces and horizontal ties. The former are so grouped as to form towers and spans alternately, but the hori/otital ties run the entire length of the structure. Speaking generally, low trestles on tangents need very little longitudinal bracing, while high ones on sharp curves need very much ; between these two, the extent, disposition and si/.es of such bracing will be a matter for the judgment of the designer, but all such braces should be bolted and not spiked, as vibration from trains will soon loosen the latter, and even bolts from the same cause and from shrinkage of timber need to have their nuts tightened two or three times before the rust locks them into place. Sway braces may, however, be partially bolted and partially spiked with pressed spikes. The posts, caps and sills are usually of solid timbers 10 inches by 10 inches, 10 inches by 12 inches or 12 inches by 12 inches in section, the latter being most com- mon. (See Fig. 57.) And such timbers make the best structures ; but large timbers are often hard to obtain at reasonable prices, and in such cases, the style shown in Fig. 58 is found satisfactory and is easy to repair and renew. The split caps, sills and posts are usually 6 inches by 12 inches well bolted together; but the cost of such bolting, and danger of some of the bolts working loose are objections to the system. On the other hand, water is not so apt to lodge or rot where timbers are so narrow. An extension of this system is the " cluster bent " trestle, the posts being of four pieces of 6 inches by 6 inches, breaking joint and bolted to split caps and sill, with the cross braces acting also as separators. This style is advisable only in localities where timber is obtain- able only in small dimensions, and of poor quality, its advantage being facility of repair ; while the trestle itself is not so stable or durable as if made with larger timbers. "4 Railway Engineering. I I-! L ' (d) Joints and Fastenings. — Fig. 59 shows the best methods in use. The advantage of mortise and tenon work is the easiness with which repairs can be effected^ but it is a favorite lodging place for water and one of the first points to rot in a trestle — a drip hole partly obviates this ; mortise and tenon work costs about $1 per M.B.M., more to frame than other methods shown. The drift bolt and dowel method is superior to the first one in rigidity, durability and easiness of erection, but is hard work to tear down, while the third method, although not in com- mon use, appears to be a very sensible joint ; the fourth method is for temporary work only, and is fastened with 6-inch pressed spike which would work loose very soon ; it is an expensive and clumsy joint, but saves timber from mutilation for a second using. Probably the best com- bination is a tenon at the top of posts and 2 dowels 8 inches by i inch diameter at the bottom, such a system avoids rot and enables pests to be easily renewed and replaced. (e) High Trestles. — When trestles are higher than 20 to 25 feet more than one story or deck will be needed (see Fig. 57), these may be either in separate bents locked by deck stringers, or they may be in a continuous bent in which the sill of one bent becomes the cap of the one below, etc. ; in the former case the four lines of deck stringers, about 8 inches by 12 inches, overlap and are boxed onto the caps and sills and gained into them, giving a lock joint. The structure is very rigid, is simple of erection and easy to repair, but needs more materj?.l than the latter method, in which the longitudinal bracing consists of four lines of girts or walings a^out 6 inches by 8 inches, which are butt-jointed and boxed about 3 inches on to the caps or posts and also bolted ; this method saves one cap and some timber in the longitudinals also, c^nd the upper and lower sway braces may be fastened by the same bolt at the cap-sill, but the trestle is a little harder to erect and much harder to repair, it is, however, on the whole prob- ably the preferable method of the two. (/) Floor Systems of Trestles, — The floor consists of stringers, ties and guard rails, and should be completed by adding some form of bridge guard like that shown on Fig. " I Railway Engineering. 135 >i 60, by which trucks not too far off centre may be brou^^ht back to direction and probably placed again on the rails, or, at any rate, carried safely across the structure. In Canada the wide-decked trestle, with two main nests of stringers and two jack stringers supporting ties 12 feet to 14 feet long, is generally used on standard gauge roads, partly to give room for snowplows inside the guard rails and partly for additional safety ; this is nowadays further supplemented by two lines of guard rails, of which the inner ones are faced with angle iron fastened by countersunk screws. The sizes of guard rails and ties are shown in Figs. 61 to 65 ; but it is a growing feeling that ties cannot be spaced too close for safety to prevent bunching in case of derailment. They should not be more than 6 ins. apart clear, at most, and preferably 4 ins., and every fourth or fifth tie should be spiked to the stringers, and all boxed from ^ in. to i in. on to them. There are some, however, who claim that if ties are kept spaced by the guard rail, and are boxed down on to the stringers, that any further fastening is unnecessary ; ties should be of oak or some durable hardwood, which will hold track spikes. The guard rails should be of pine, or some durable wood that will not warp, and boxed down about i^ inches on to the ties, so as to hold them apart, as well as to act as guard rails. They should be bolted on outer ones and spiked on inner ones to about every fifth tie. There are various styles of stringers ; that shown on Fig. 61 is now almost standard for Canada. It consists of alternate groups of two and three stringers in two nests, one under each rail. These stringers are long enough to lap one foot and rest twelve inches on the caps, and are bolted together, but separated by cast washers to prevent rot, and each nest is drift bolted down to the caps. The outer or jack stringers carry very little of the load and are butt jointed, and also drift-bolted to the caps. The style shown in Fig. 62 is practically obsolete, being con- sidered rather top heavy and demanding too heavy tim- bers ; the corbels also give a very uncertain aid to the strength of the stringers. The style shown in Fig. 63 is used considerably in the United States. The stringers are 32 feet long, alternating with butt joints, and make ■1 wmm 126 Railway Engineering. a very stiff floor ; but such large timbers are hard to obtain and harder to take in and out during renewals. One advantage, however, is that all ties will have the same boxings, while in Fig. 6i, the length of boxing /^/afe XVIII ^pieces V»l6'n l6'/ong apieers a'*'6''/6'/»^- a-. /♦■■/.^ '^'"{'X i \ Sett /f cen^s. F,g62. *»vtV/<>' mtf f^f't v'trt j}-4ifr^ tr^e/ tSfftg/e sAee-^/>i/.'rr^. /^Jf: €8 Co/^ar -e/o/fra f»r .fAo/^nr /roi^r. i*ft/. N '^' U).,r»'lt>" ' >'V»'»»>'rti>" ' »" ""J"--'""' ^;g. TO f/oatt!^ Co/^»rc/om On /»*/«e Cat'sson. Railway Enc.ineering. »35 in general, consist of vertical hand-driven sheet piles and horizontal rings of timbers and braces to sustain them at five or six foot intervals, as shown Fig. 67, Plate XIX., and in planning such work it is well to remember : (i) To allow for extra room more than is apparently required, in order to give freedom of movement, extra timbers, etc. ; (2) To be sure to find out how deep it is to good bottom before digging is begun, in order to see whether piling might not be less expensive, and chiefly so as to be able to say definitely how many rings of timber there will be, and how much extra room will, therefore, be needed to step in all around about 15 inches every 10 or 12 feet in depth ; this is a very important consideration. See Fig 67. lOUNDATIONS IN WATER. When masonry work is to be built in water, the con- siderations which determine the method to be adopted are : (i) The depth of water and its fluctuation in level. (2) The depth of soft material underlying the water which must be penetrated to secure good foundation. (3) The velocity of the current. (4) The money and materials available. Of these considerations Nos. i and 2 are most import- ant, and the total depth from water surface to bottom of structure will determine whether the foundation should be obtained by : (A) Fixed cofferdams ; (fi), floating coflferdams, with solid timber bottoms ; (C), bottomless cofferdams or caissons ; (D), compressed air ; (£), open dredging. Fixed Cojfferdams. — These are used where there is shallow water, at most only a moderate current, and where the bottom is of such a nature as to admit of sheet piles being driven in and the foundation suitably excavated to a firm foundation bed. This rray be accomplished in various ways. Where the structure s near shore and waste exca- vation is available, it will pay to make an embankment above water level, and carry down hand-driven sheet pilet; kept in position by rings of timber, the excavation being always kept about level with the bottom of the sheet piles. This method is illustrated in Fig. 67. If, however, the structure is not thus situated, the sheet piles are either driven in a double layer, as in Fig. 68, 136 Railway Knginbbring. 1: or a single row of Wakefield sheet piling is used (this is an artificially made sheet pile composed of three planks spiked together to form a tongue and groove). If any of these methods are employed, a centrifugal pump will be kept busy keeping down the water while the founda- tion courses are being laid, but in case such pump- ing power is not advisable or available a more expensive form of cofferdam can be used, as in Fig. 68. Rows of guide piles are driven at considerable distances apart, then walings are bolted on, and a double row of sheet piles is driven around the area to be unwatered, between which is rammed clay puddle, making a very watertight, but expensive, cofferdam. This is generally employed in extensive works where the area is to be unwatered for some lengili of time. Floaiinq; Cofferdams ivith Solid Timber Bottoms — It is moderately certain that as long as timber is covered with running fresh water it will never decay, and it is even contended that in any fresh water it is practically safe also ; this has led to the adoption of methods o*" foundation building which do not involve the unwaterin of the bottom. If the bottom is bare and moderately level, or can be dredged to a good bottom and levelled up with broken stone, it is manifestly easy to build a water- tight box with either a solid timber (Fig. 69) or stone- filled crib, or only a plank layer, as a bottom (Fig. 69), and, after floating it into position, sink it, by building in it or by external loading, and after the structure has been built up above water level tear off the sides of the water- tight box, leaving the bottom as a permanent part of the structure. If, on the other hand, the foundation is soft and good bottom can be reached by piling, the piles are driven to a firm bearing, sawed off under water close to the bed of the river, and the same operation as just described is gone through, the structure being landed on top of the piles as a foundation, as in Fig. 70. These methods are cheap and satisfactory in situations where the current is not excessive, but in very cwift currents such constructions are not as manageable as the bottomless cofferdams to be described, and e^'en where used, it is found advisable to build the timber work and footing courses of masonry considerably (i to 2 feet) larger than HAir.wAY ICn(;inhering. «37 the neat work, which is laid out after the crib is in its final position. This providrs for sotnt; permissible inac- curacy in sinking. The cribs arc well drift-bolted together and the boxes caulked with oakum and dove-tailed or bolted down to the bottom, so as to prevent them liftitig when the sinking process is going on. /iottomless Caissons or Cofferdnitis. — Where no timber is desired under the masonry, or where the current is very swift, the method shown in I'ig. 71 has been found best, but is only admissible where good foundations are easily obtainable. The bottomless box is lloated into place, loaded until it sinks to the bottom, and then is eith»'r unwatereil by having a large canvas flap around the out- side of the bottom, held down by bags of concrete, thus nearly sealing the bottom, the caisson being then pumped out and the bottom excavated or levelled off with con- crete, or else, if the bottom is already firm, as is usually the case in swift currents, there is no necessity for un watering untd a great depth of concrete has been put in, forming a watertiglit bottom ; in tin; latter case, if there is an irregular rock bottom, the caisson cannot be made to fit it, and in order to keep the undertow from carrying away the con- crete as fast as deposited, or at least dissolving out the cement, it is found necessary to fasten a canvas flap around the inside of the bottom and load it down with bags of concrete, pea straw, etc., until a bottom has been formed And in depositing the concrete it is done by lowering an iron box, with a hinged bottom, containing about one cubic yard down to the bottom ; the box is tripped, allow- ing the concrete to slide gently out, whereas it would become dissolved if allowed to fall any distance through water. After such a bed of concrete has been formed as is considered sufficient, the caisson may be pumped out and construction continued in open air. Compressed Air, — Where a great depth of water and soft foundations are encountered the methods previously described must be abandoned. Early in this century the vacuum air process was tried, by which the excess of outside pressure forced soft materials up inside a vacuum chamber, this material being excavated, air was again extracted, and each time the hollow chamber of wood or iron sank down by its own or added weight ; but this 10 138 Railway Engineering. M method was found uncertain in its means of directing the sinking, was capable of only limited application and failed entirely on encountering stiff clay or boulders, besides it did not enable the bottom to be personally examined and properly prepared for the foundation layers. Very soon the plenum or compressed air process was tried, and to-day it is recognized as being in every way TAOst satisfactory until greater depths than about loo feet below water level are to be obtained, when open dredging through wells must be resorted to. Figs. 72, 73 and 74 show common forms of the same process. The drawings are almost self-explanatory, the pressure of air in the working chamber is constantly maintained, and the extent of the pressure must always be sufficient to keep out water ; the tendency being for compressed air to be con- tinually escaping around the working edges, and bubbling up to the surface outside the chamber. Where pneu- matic cylinders are used, they are in pair?, sometimes braced together, the two supporting one end of a truss, and being completely filled with concrete after bottom is reached. See Plate XVI. One larger cylinder, as in the Hawkesbury bridge, with elliptical ends will, however, be mucii more stable. Where large timber working chambers are used they must be very strong, as the whole weight of the pier will be carried on their backs until the working chamber is filled in, which is not until firm bottom is reached. It may be shod with iron or merely with timber, depending on the materials to be met with, and on top of this cham- ber may first be constructed a timber crib as in Fig. 74, extending up to the ground surface and filled with alter- nate pockets of concrete or broken stone sufficient to sink the chamber, which crib is built up gradually as the process goes on. Or, if advisable, the masonry may be commenced immediately on top of the working chamber as in Fig. 73, this will usuLslly be done where the founda- tion is not a very deep one. The support which a deep caisson sunk by this method, or by open dredging gives to a pier and bridge, is partly by the bearing on .he bottom and partly by friction on the sides, which is jstimated at from 300 to 600 lbs. per square foot of surface, and is an Railway Engineering. 139 enormous item in such a structure as that of Fig. 74, amounting to 2,000 or 3,000 tons. Of course, this resist- ance is not all to be overcome while sinking, for the con- tinual movement and escape of a film of compressed air tends to aid sinking by lessening friction. r/a/e XX K fi -mi/teL. , r^fff^^ ^a V7* •^ ^ II tit-"*'' Hit^£^ ^ tfze/ i-ert/ OMd , }^^ '/.■-■ f/g 72 Pffumefic f'f» ^^S- ^^ /^ntumofie Co/'sson. 3BEIiE3B P/OfOlTlb/t. HoHx. •S9ct/en. /^ig. 74- F/>eumet/G Ca/ssen f/g 75 0/>er? Otee/^/n^ Cr/A ^^Co/yer^om Caisson % P^er The material to be excavated is forced out of the dis- charge pipes by the compressed air, if it is finely divisible, by opening valves at the mouths of flexible pipes, but boulders, gravel, logs, etc., must be laboriously taken out 140 Railway Engineering. of the air lock in small quantities, making the operation costly. The air shaft and lock form the means of ingress and egress, and it is a question whether it is safer and more convenient to have the air lock near the top or bot- tom of the shaft, the former, however, being safer for the men. The process of working the lock is to open one door, pass in, close the door, open a valve so as to raise or lower the pressure as the case may be, and then open the other door and pass on, some time being necessary to prevent injury to the lungs and ear drums ; men can work in about 4 atmospheres pressure as a safe maximum, and then only for three or four hours for healthy men ; with less pressure the period of labor may be lengthened, but on coming out to the open air the depressing effect of a lowered pressure must be connteracted by a strong stimulant like coffee, to prevent injurious consequences; and for reasons of safety the compressed air is taken from a receiver and not direct from the compressor. So that an accident to the machinery might not have an immediately disastrous eflfect by per- mitting an inrush of water before the men could escape. The supply shafts marked are only used at the last, where concrete is passed in through them, to fill up the working chamber. The shafts themselves are also all filled with concrete, and the whole structure is a solid mass of timber, concrete and stone. Sinking foundations by compressed air has many advantages — the sinking can usually be quite accurately directed ; it enables all the pier construction and excavation to proceed together ; it enables all kinds of materials to be removed, and it permits of a careful examination and preparation of the bottom before concrete is put into place. An example of such construction is detailed in Pat- ton's *' Foundations," at a cost of $16.82 per cubic yard for the caisson material ; $10.76 " " crib •• $7.83 " •' sinking " making an average of about $20 per cubic yard. This was for a depth of 68 feet below water and in 56 feet of mud — evidently the cost would vary with the depth and the materials encountered, in this case the sinking was at the rate of i^ to 2 vertical feet per day. Railway Enginhkring. 141 Open Dredging. — This method has been long practiced in India, where circular brick wells are built with heavy walls, and gradually lowered through soft soils by exca- vating and undermining, the material being raised in some primitive manner. This is improved upon now by using steel cylinders and excavating by clam-shell or other dredges. There is usually difficulty in controlling the direction of movement, and large logs and boulders are troublesome, so that open dredging is usually used only where the depth is too great to admit of using compressed air and where the materials can be freely dredged (in India, submarine blasting of boulders, etc., tended to crack the cast iron cylinders, but would, prob- ably, not have a bad effect on timber cribs). A striking example of this process is that of the foundations for the Poughkeepsie bridge, which were sunk through a depth of 50 to 60 feet of water and 75 to 80 feet of mud, clay, sand and gravel, or a total distance of 140 feet below high water. (See Fig. 75.) The cribs, 100 feet by 60 feet, had 31 gravel pockets, extending from top to bottom, which afforded enough load to sink the cribs when undermined; there were 14 dredging wells extending from top to bottom 10 feet by 12 feet, in cross M'ction, through which the dredging was done by a clain-shell dredge. The walls were 2 feet thick of ilid timbers, laid in alternate lapping courses, well dni: -bolted together, and after the cribs arrived at good bottom the wells and pockets were filled with concrete, and a floating caisson simil ir to Fig. 6g was brought out into position and built into until it sank on to the top of the crib. The chief difficult, es in carrying out thi? process, aside from anrlioring such a huge mass of timber in a swift current, preparatory to dredging, are that it is difficult to guide the crib in direction as it settles down, and that logs, houli rs, etc., under the cutting edges, cause delay and jcessitate, often, sending down divers.' A combination of compressed air and open dredging has been used in Europe, in which several working chambers surround an open well, the men force the material out under the inner edges of the working chambers from which it is removed by a clam-shell dredge ; the process is cheaper in handling the material, but uses an enormous quantity of compressed air. V,-- 142 Railway Engineering, article 28. — laying out and measuring work. Cross-sections should be taken at such intervals that the prismoid between two adjacent ones will have planes as boundaries or a top surface with longitudinal convolu- tions only, extending in straight lines from one section to the other ; to do this quickly and without unnecessary sections is a matter of experience and visual judgment, requiring the personal attention of the engineer. The jP/aUXXI ■StAA* ,'SSAiAt F/g. 7T Ore/t '/nary yAr !Y *y£' 76 Sectr'on on uneven ifrcune^. ^ r1^---X Sec/zons. Railway Engineering. H3 slope stakes should be marked on one side with the cut or fill and on the other with the distance from the centre line ; some engineers also write the station (chainage) on the slope stakes. These stakes are put in at every loo feet for light work and on tangents, but on curves and heavy work they should be put in every 25 or 50 feet, depending on circumstances, and on all side-hill work, liable to slip, the sections should be carried up the hillside 200 or 300 feet to points beyond any danger of movement, and should be taken before excavation has been com- menced. I There are two methods of keeping notes in use in Can- ada ; in the first, each rod reading is entered in a separate line and the corresponding cut or fill reduced from the grade elevation ; in the second method the difference between height of instrument and grade is called "grade rod," and the rod readings are subtracted mentally from it, and the corresponding cuts or fills are recorded, consecu- tively, on one line of the book in the form of fractions, with the distances from centre line as denominators. It is evident that the first method is more laborious and fills much more space in a note book, and is not so convenient for plotting, but, on the other hand, the reductions can be checked afterwards, and are legal documentary evidence, whereas the second method is entirely one of convenience and leaves great chances for error by careless mental subtraction, which cannot be duplicated, and the note books are, therefore, not very strong evidence in a law court. • _ ■ . • The following are notes of surface levels of Figure 79 taken by both methods : • Station. 102 . . . 2 R.. 8 R.. 20 R.. 3L . 22 L. . B. S. (I) English Method. H. of I. F. s. Int. S. Ground. Grade. Cut, Fill. Remarks 311.20 10.2 301.0 293.0 8.0 .. • ■ . . 10.7 300.5 7-5 .. , , • ■ • • 12.2 299.0 6.0 .. . . » 1 . 2 3 ^0 . 70 .. s. s. . . 9-7 ;^oi.5 8.5 .. • • ■ . 10.2 3 )i .0 8.0 .. s.'s. (/} n o X 311.20 00 fa (II) United States Method. 0) u o 293.0 •a 02 Lpft. Right. u -fS.o -»-S,5 +8.0 +7^5 ^o 7.0 18.2 vS.S.1 2^^ - ^ ^ ^^ ^ ^ ^ g^ + — ^ (8.S.) 144 Railway Engineering. 1 The greater simplicity and convenience of the second method commend it to general use in spite of its deficiencies. On some roads it is customary- to take sections after the work is done, and pay for the actual quantities exca- vated ; in others, the slope lines are adhered to and every endeavor is toward having the full section taken out. It is probable, however, that the former method is more satisfactory to all concerned, although giving a little extra work to the engineering staff. Structures need to be staked out twice, once for the foundation pit and again for the laying out of masonry, and of course, on all important structures, measurements and levels are given very frequently as the work pro- gresses, both as an aid and a check to the contractors. A separate note book called a "structure book " should be used, and in it recorded, from day to day, notes of actual sizes, heights and measurements of all structures, and a duplicate office copy also kept up to date for fear of losing the field book. This structure book should include notes on all timber, stone and iron structural work, and will be a valuable aid in case of disputes involving quantities, it will also enable a large scaled profile being made for the maintenance department showing the exact chainage and elevation of each foundation and portion of structure. The necessity for absolute accuracy m laying out, measuring and calculating the quantities in all structures and grading cannot be too firmly imprtssed on the young engineer ; all office calculations should be made in duplicate and prefer- ably by different persons, as one cannot be very sure of a check on one's own work. ^^055 Section Areas may be calculated in at least three or four ways, (i) where only a three-level section is taken, as in Fig. 77, the area of the section is evidently made up of triangles and is : Area=(.><^4-«^)+(|x'Zi-ti'«) (.) (2) On rougher ground where more than three surface readings are necessary this method fails and must be replaced by more tedious ones, quite ordinarily Fig. 78 illustrates the one adopted, and consists in taking out the Railway Engineering. 145 sum of all the trapezoidal areas, A.A.^D.^D.E.F.G.H.A. and deducting the area of the two triangles A.A.^B. and D.D.^C. (3) By careful plotting, irregular areas can be taken out quite accurately with a polar planimeter. (4) By Eckel's formula, which can be used without plotting the sections, and is equally adapted to the easiest or most difficult rectilinear areas. This formula, which is mathematically correct, is : "If the corners of any rec- tilinear polygon be referenced by rectangular co ordinates to any origin, then if the ordinate of every corner be multi- plied by the abscissa of the next corner, and so on around the polygon, and these products added together; and if the ordinate of every corner be again taken and multiplied by the abscissa of the next corner, passin<^ around the polygon in the reverse direction, and these products added together, then the area of the polygon is equal to one-half of the difference of these two sums." As an example, in Fig. 79 the area of the polygon is i { [(rt X d) + {c X f)+ i-ex- h) 4. (-«• X _ /) + (* X b)] — {{ax -/) + (* K - A) 4- (-,^ x/) + (-. xd) ■¥{c^b)]] (2) or, ^{ (a X rf) 4- {c Xf) 4-(6' X h) + (g xl)+{kxb) + {a x I) + {kxh)^{gx/+{exd)-{cyb)} (3) In which great care must be taken to use the correct plus and minus signs. In railway work, this is much simplified by having all the area above the axis A'X., and in very irregular areas, which are met with in cuts that have slipped in as in Fig. 79, the area can be quickly taken out, thus, as follows : — + 8.0 +85 4-8.0 +7.5 +6.0 +7.0 bection = • I — , u '• , ~22.0 ""3-0 00 +2.0 4-0.0 -f20.0 4- 3.0 4-0.0 4-0.0 4-0.0 + 2.0 + 4.0 4- 8.0 + 13.0 -fg.o 0.0 —9.0 -14.0 —16.0 —22.0 Area = ^ { — 24.0 4- 16 o -f- 60.0 4- 120.0 4- 9i'0 -f- 27 o — 32.0 — 88.0 4- 128.0 4- 56.0 4- iS-o — 6o-o - 56.0 - 12.0 + 24.04- 187.0} = 227.5 square feet. Thus arriving at a correct result without plotting sections, and by a mechanical sort of process, which is a safe one 146 Railway Enginebring. i to place in the hands of a comparatively unintelligent rod- man ; for the purpose of checking calculations, it is not appreciably more or less rapid than by taking out areas by method. (2) QUANTITIES. The use of tables and diagrams is a great aid in taking out approximate quantities, so that in various handbooks may be found the volume of 100 foot prisinoids of level sections, of various heights, slopes and widths of road-bed, and this has been extended in Wellington's earthwork diagrams, etc., by giving the volumes of 100 foot prismoids where the sections, although not level, are of the three- level type, having a separate height at the centre and each slope stake, and as in easy sections this is all that is taken the diagrams are very useful. More accurate calculations of volumes of excavation or embankment may be made in three ways: (i) The prismoidal formula, which is the only one that is mathematically correct, is as follows : — Volume = L x > ' (4) Where L = length of prismoid A and A^ = end areas and yi , = middle area (which must be calculated by inter- polating the middle heights). A proof of this formula may be found in any mathe- matical text book, but a neat adaptation of the formula for three-level sections is given by Mr. G. H. White in Engineering News, April, 1895 (see Fig. 80). Volume = ^ L I ^ -f 4^ J +/1 3 f = iL bH^4.h, + 4 [i 4^ 2\ 2 2 K W.d W.d W.d, -f- + ■ H J W„d„ W^d 2^2^ (5) W'd, ] .(6) (7) Railway Engineering. H7 and if we have a definite si>pe which we call s. (say i^ to I for earth, or i^ to i for rock), we will have ^^3-26 («) and the volume equation becomes {W+\V,-2b) ] (9) from which it will be seen that the volume may be obtained by having the slope stake distances of the two end sections {W and W^), the centre cuts (rf and d^) the roadbed width {b), and slopes (5), thus eliminating the determination of the middle area from the calculation. (2) Mean areas, which custom has established as the one to be ordinarily used, because of its simplicity, is M merely, volume = L where A and A^ are the two end areas, the error involved in this formula is + ^L {h —h^Y s. Where h and h,j are the two centre heights, and 5 = slope of earth work, it is evidently = zero when li = h^ and increases with their difference. (3) Middle area volume is given by Volume = LxA^ (11) Where A , = area of section midway between the ends of the prismoid. The error involved in this formula is +y^ L{h — h^)^s, being one-half as much as in the formula for mean areas, and also disappearing, when h = h^ — and although equation (11) is more accurate than equation (10), it is not used, be- cause once the middle area has been determined, the pris- moidal formula is easily applied and still more accurate. There is another reason why formula (10) is not objection- able, that, in general, the profile of a line is convex in cuts, and concave in fills, and any system of sections, no matter how carefully taken will, as an average, need a little allowance for this rotundity between sections. At points where the cut changes to a fill there should be two grade pegs determined (see Fig. 76) and cross- sections taken at these points, this makes the first volumes I 148 Railway Enginekring. in cut and fill always pyramidal, there is no necessity for a centre (?rade peg, unless the distance from one grade peg to the other is excessive. Borrow pits should bo carefully cross-sectioned from some well defined base line before excavation is permitted, and, if at all possible, it should be made imperative that these pits before being abandoned should be left in good shape for final cross-sections and for drainage ; undrained borrow pits are unsightly, a menace to health, and diffi- cult, often, of measurement. There is another matter in this connection which should be well attended to, i e., proper referencing of alignment hubs ; this may be done by cross lines fixed by hubs, trees, etc., or by right-angled lines and steel tape measurements, but in whatever way accomplished, considerable judgment is required to place the references out of harm's way and at the same time reasonably available ; in side-hill cross-sections made after excavation great piecision is required in this respect to prevent serious error. ARTICLE 29. — METHODS OF PAYMENT AND CLASSIFICATION OF MATERIALS, ETC There are occasional instances of railway companies of some financial strength and progressive growth carry- ing on construction under their own management, with their own plant and by day labor, but such instances are not frequent, and in general we may look to responsible contractors for the rapid execution of this kind of work requiring experience, undertaking risk, and with consider- able capital as plant continually wearing out. Occasion- aliy such work is taken by contractors at so much per mile, within limits of curvature, grades, style and locality, but as the element of risk is great the price is correspond- ingly high. Only approximate estimates are furnished, and the experienced judgment of the contractor to size up the class of material to be met with is his chief reliance. Such contracts are apt to be made when the railway company and the contracto. are more or less identical. Again, at times, contracts are taken in which such as timber, stone and iron are specified as to quality and price pro rata, but the excavation is unclassified and an $ KaIIWAV liNGINEERING. 149 average price per cubic yard is Riven, the contractor again taking chances, and being, by this method, unable to alter the location, his risk is great and price high enough, on the whole, to cover the risk ; this has led up to what is, at pre- sent, the general method of letting contracts for excavation, namely, to define certain classes of material as rigidly as possible and fix prices for each class, the usual divisions are solid rock, loose rock, hard-pan and other cemented material, and earth. As the dividing lines between these classes are purely arbitrary they need to be defined for all possible contingencies, which is a difficult matter. An engineer is always, although in the employ of the railway company, more or less an arbitrator, and he should endeavor to be just to all ; theoretically he should always live up to the strict letter of the contract, and ordinarily this is the only course to pursue, but there are casf.s in which contractors, in their eagerness to obtain contracts, take them at too low prices, or they may strike some very difficult cuts which will not classify very highly if the specifications are adhered to, and in such cases it is usual to allow percentage classifications based on a fair cost of doing the work, e.[![., a heavy cutting comp ised of a mass of small boulders cK sely cemented together would only classify as hard par t often must be excavated entirely by drilling and blasLiag, and in such a case percentages, at least, of rock would be quite justifiable. This idea of helping out a contractor, however, is a very pernicious one, and should only be done for good cause, where the recipient is worthy of it by his economi- cal handling of the work, and with full knowledge and consent of the railway company. The vigilant watch and full knowledge of the various classes of material met with in excavation and the most economical methods of handling them, form one of the most important duties that a railway engineer has to perform, needing, more- over, a knowledge of men as well as ways and means. The calculation of quantities in structures should be made very minutely and in detail, as the prices are so much higher per unit than those of excavation ; but the method to be used will depend on the terms of the contract and the individuality of the engineer. In some cases payment is made on bills of timber furnished, and on general plans of 150 Kailway Enginbkking. I masonry, while in others the actual timber used and the masonry as built are the basis of payment. In the case of timber this latter method should include payment, as tim- ber delivered, for all pieces cut off either from piles or tim- ber, so long as the material used was' as per bill given. Quantities of earthwork should always be measured in excavation, for no one can determine accurately the shrink- age of fills, especially as only a portion of it takes place while construction is in progress, and continues for a year or two depending on the method of forming the bank. The total shrinkage is fairly well known, being about 5 percent, for sarid, 10 per cent, for clay, and 15 or 20 per cent, for loam ; while rock expands 50 to 75 per cent., depending on the size of the pieces, and such figures modified according to the age of the bank will be sufficiently accurate for monthly estimates, but not for final ones. It is more labo- rious, often, to measure irregular borrow pits, but by insisting on these pits being shaped up before being left, the extra labor is not so very great and is the only really reliable way, the chief value of embankment quantities being to aid in a proper dis- tribution of material from cuts, to enable overhaul calculations being made, and for approximate estimates where errors of 5 per cent, or even more are not objecti )n- able, as the company, in its monthly payments to con- tractors, reserves 10 or 15 per cent, for just such exigen- cies. In taking monthly estimates, the only certain method is to make each one a total estimate in fact as well as in name, and derive the current estimate by deducting the total one for the month previous from it, that is, never take notes only of what is thought to have been done during the month, for nothing is more difficult or more apt to lead to error — whereas if the total work done or material delivered at each point is noted, the errors of each month are eliminated in the next one — the extra labor involved in this is usually insignificant. Specification for Excavation. — Materials excavated will be classified as earth, quicksand or dry hard-pan, loose rock and solid rock. Earth includes everything except the other classes mentioned. Hard-pan includes all cemented clay or gravel, or any combination of these Ram.wav ICn(;inkkrin(;. »5i that it is not practicable to plow with a four-horse team. Loose rock includes all stone containing not less than one cubic foot, and masses of detached rock containing not over one cubic yard ; also all slate, shale or other soft rock which can be removed without blasting, although blasting may be resorted to. Solid rock includes all loose rocks containing over one cubic yard, and all rock in place which retjuires drilling and blasting. (N.B — .The earth and hard-pan are sometimes placed in one class as earth, at a higher rate, thus saving much contention.) ARTICr.R 30. — SUKTACK DKAINAC.E. In addition to the provision .for How ok water under or through the track, there is yet the question of track and slope protection which is of almost equal importance. Where, on side-hills, the surface flow toward the top of the cut slopes and toe of the embankment slopes is con- siderable, ample provision should be made to intercept it. In general, catch water ditches three or four feet wide, and one to one and one-half feet deep, should be dug so as to run in a continuous line along the upper side of the cuttings and embankments from each lateral watershed to the nearest culvert or stream — which should set back five or six feet, generally, from the edge of the slopes leaving a solid berm ; the material from these ditches, cast on the lower side will form an additional protection. In very porous soils, these ditches may need to be lined with pitch or planked ; but in any case will prevent that heavy washing down of cut slopes which, otherwise, hlls up the track ditches and floats the track, making the roadbed soft. The track (cut) ditches themselves should be turned into these catchwater ditches at the upper grade points, so as not to empty down along the toe of the embankment, eating it away ; and in very wet cuttings, it may be neces- sary to run a farm tile about three feet under the track ditches and parallel to them to aid the drainage. In case of quicksand, which will soon fill up tiles, the tile must be covered with straw and laid with collars, or longitudinal round pole drains may be substituted for the tiles. I'52 Railway Engineering. The slopes of cuttings themselves also need protection lO prevent erosion ; in ordinary cases the sowing of fjrass seed on the slopoii of cuts and fills will answer the purpose, but where the cut slopes are wet and springy it may be necessary, in addition, to cut ^ series of diagonal ditches on the slopes to bring the water to the cut ditches by easy grades ; in extreme cases the construction of a network of tiles on the slopes may be necessary to effect complete pro- tection. Perhaps the most imperative matter of all is to have the ordinary cut ditches always cleaned out — free from boulders, ties, ballast, etc., which tend to accumulate during maintenance. The form which such ditches assume is of a wedge shape, with a slope from the track of about 3 to I and an wuter slope the continuation < *■ the cut slope. This form will tetid to maintain itself better than one with a flat botton) and steeper slopes. Railway Engineering. 153 CHAPTER VI. Raiuvvav Law. Railroads being recognized as public necessities have had great powers conferred on them by legislatures, which have also necessitated many legal restrictions to prevent the abuse of these powers. All of which in Canada has in time become formulated in the " Railw.ay Act." This Act defines, amongst other things necessary for a railway engineer to be familiar with : — I. The powers conferred on the Railway Committee of the Privy Council for regulating traffic, tolls, returns, methods of operation, of construction, capital stock, and distribution pf gross revenue obtained. II. The privileges and powers granted to railway com- panies. III. The duties of a railway company to the Govern- ment and to the Privy Council. IV. The duties of the railway company to the indi- vidual, and the rights of the private individual. Much of the matter contained is rarely needed by the engineer, and the following extracts cover the main inform- ation which he is likely to need in the course of construc- tion and maintenance. I. — POWERS CONFERRED ON THE RAILWAY COMMITTEE. (a) To regulate the speed through various classes of cities, towns and villages — which is not to exceed six miles per hour in any case. (6) To regulate the use of steam whistles in towns cities, etc. (c) To regulate the means for passing from one car to another, for the safety of employees, and the methods of coupUng cars. {d) To impose fines for offences under these clauses. II Il'f 154 Railway Engineering. I! (e) To enquire into, hear and determine applications, disputes or complaints regarding right of way and location questions, constructing branch lines, the crossing of one railway company's tracks by those of another railway company, the construction of railways along or across highways or navigable waters, tolls, rates, running powers, trafRc arrangements, unjust preferences, discriminations, distortions and the carrying of highways, streets, ditches, sewers, etc., over or across the lands of a railway company. (/) By itself or agents, it has full legal power to enter on to the property of a railway company to examine books, plans, etc., to summon witnesses and in general it has the same powers as a law court. (g) The inspecting engineers of the Privy Council are to have every desired information, in reason, supplied to them on demand. They are to be carried free while on inspection trips, and to have the services of all company telegraph operators free while on Government business — penalties for obstruction of the inspecting engineers are also defined. II. — THE PRIVILEGES AND POWERS OF A RAILWAY COMPANY. These are given with the view of assisting the com- pany in overcoming any obstructive measures of a corpora- tion or individual, where it is evident that the public would be best served by the construction and operation of a railway. These powers should be thoroughly considered by a company's engineer before taking any steps likely to incur the ill-will of the public, to whom the company must ulti- mately look for its income. (a) The company or its agent may enter on crown lands or the lands of any person or corporation whatever for the purpose of survey and location. (6) It may purchase land for the use of the railway, and may sell what it does not need. (c) It may build anywhere within one mile of the first located filed line, or within any further distance prescribed by the special Act. Railway Engineering. 155 ■V, % it (In the Act a railway is said to be near to another when some part of one is within one mile of some part of the other railway.) (d) It may fell trees within 99 feet of either side of ihe railway, when they are liable to fall across the track. (e) It may cross or join any other railway, and enter on its lands. (/) It may divert temporarily or permanently streams, highways, water or gas pipes, sewers, drains or telegraph or telephone poles, but must restore them to their former state, if possible, or put them in a state not materially altering their usefulness. (Note this with reference to keep- ing them usable during the construction of the roadbed). (g) It may construct, operate and keep in repair its road, together with the accessories commonly belonging to a railway, and may carry traffic and collect tolls, and may, in general, do everything necessary to a successful ope- ration of its enterprise and the accommodation of the public, but in the exercise of these or other powers the company shall do as little damage as possible, and make full compensation for damage done or loss inflicted, in a manner prescribed in the Railway or a special Act. The essence of these general powers is compensation. It is the limitation of what would otherwise be absolute, arbitrary powers. II. — (a) POWERS WITH LIMITATIONS. (a) No person who holds a contract for work with a railway company can be a director on its board, nor can a director or officer of a company even go surety for a con- tractor. (6) The first charges on the income of a railway com- pany are the penalties, if any, arising from this Act. The next are the working expenses of the road, and the third are the bonds — the latter, however, all having equal claims in proportion to remaining assets. (c) The consent of the Governors-in-Council is neces- sary before Crown or Indian lands can be entered on, and in the case of Crown lands the right of way only, i.e., an easement, is all that can be obtained, and not ownership or full possession. 156 Railway Engineering. I; f i li .; II i! (d) The consent and approval of the Railway Com- mittee must be obtained before possession or use of the land or property of another railway company can be effected. (e) The ordinary amount of land obtainable without the consent of the owner is 99 feet, while exceptions are authorized by the Minister in case of deep cuts or fills and depot ground^ which is in general limited to a tract of land 1,950 feet long by 300 feet wide, but any extent of land may be purchased with the consent of the owner. Extra land is to be shown on the maps or plans filed with the Government. (/) After fihng plans (to be afterwards explained) the company may take possession as shown on those plans, and settle afterwards, amicably or by arbitration. This is a very necessary power, for otherwise contractors would be kept off the land for indefinite periods, the progress of the work impeded and a good chance given the contractors for suits for damages caused by delay, or for excuses for slow progress. (g) The company -may enter on lands not more than 600 feet from the located line, for purposes of construction or repairs, without consent of the owner, provided a sum of money, fixed by a judge of the Superior Court, is deposited with that court, pending the award for damages. (h) Power of surveying and arbitrating in the usual way is also given whenever the company desires extra land for stone, gravel, water or earth, or on which to construct sidings or branches, or on which to convey water to the company's works. (i) The company may occupy "land between ist November and isfr April, with snow fences, subject always to damages as a court may decide. (j) No lateral deviation of more than one mile shall be made from the original location, except under pro- visions of a special Act. (k) Error in name or omission of the same from plans and txjoks of reference does not prevent tlie company from entering on land so affected. Railway Engineering. 157 III. -DUTIES OF A RAILWAY COMPANY TO THE GOVERNMENT. (u) On completion of location surveys, plans and books of reference showing all properties asked for, must be forwarded in triplicate to the Minister, who after ten days' notice to all interested parties, hears all counter claims and representations, and the plans, as finally decided on, are signed by the Minister, alter which one copy is retained at the department, another is deposited by the company in the office of each municipality affected, while a third one is given into the hands of the company itself. After these proceedings following the action as described in Art. /, powers with limitations. (b) All extra widths desired must be shown on the plans filed. (c) Any change from the original plans or profiles must have separate plans, etc., submitted and deposited in the usual way before the alteration can be made. (d) Ten days after plans have been filed in the offices of the municipalities (registry offices) and notice published in a newspaper, a notice may be served on the interested parties owning land, giving 1. Description of land required. 2. Amount offered by the company for land or damages. 3. Name of company's arbitrator if the offer is not accepted. Such notice to be accompanied by a sworn statement of a surveyor or engineer (not an arbitrator) stating 1. That the land is needed as described for the pur- poses of the railway. 2. That he knows the land, or damages likely to result, from the railway being built and operated. 3. That the sum offered ic, in his opinion, fair com- pensation. (e) Should the offer not be accepted, arbitration is resorted to. This is usually outside the province of the engineer, except in giving evidence and preparing plans, but it may be useful to remember that, in considering the value of land taken or amount of damages done, the increase of values of lands adjacent (i. e., of same plot) not taken by the company, which is created by the construction of the ^s; is i It I PI t '■ 1 S 158 Railway Engineering. railway, is to be taken into account and offset against any damage inflicted. (/) Before a company can unite with or cross over any railway with its roadbed or track, it must submit plans and full details of proposed mode of crossing to the Railway Committee, and give ten days' notice of applica- tion to the other company affected. The committee may make such changes or regulations as appear necessary for public safety, and apportion the cost of constructing the necessary works to the different companies, and may also, in case of level crossings, on application of either com- pany, direct such 'nter-locking signal system or device to be used as, in their opinion, renders it safe for engines to pass over such crossing without coming to a full stop. This clause also applies to electric and other street rail- ways. (g) When the railway is finished, plans and profiles in tripHcate of the completed work, showing land taken, names of owners, etc., must be filed as in the original survey or alterations within six months after completion of the railway, undev penalty of $200 fine per month. (h) The scales of plans and profiles are to be as pre- scribed by the Minister ; they are usually : Plans, 400 feet to one inch ; profiles, 400 feet to one inch horizontal, and 20 feet to one inch vertical, and are to be all signed by the chief engineer or president of the railway. (i) Within 48 hours at furthest, after any accident has occurred on a railway line, involving personal injury, or the damage or destruction of any structure, the railway company must notify the Minister of the same under $200 per day penalty. And, if necessary, the Privy Council may appoint a commissioner to enquire into the causes, etc,, of the same. (j) Annual returns from ist July to ist July must be forwarded in duplicate to the Minister within three months after the expiration of such financial year by each railway company, of its capital, traffic, working expenditure, and any other information shown on the blank forms furnished. (k) Weekly returns of traffic shall also be furnished the Government within one month after the period quoted, and a copy of the same must be posted for public view in the head office of the company. Railway Engineering. 159 (/) Twice a year accidents and casualties must be similarly reported within one month after each six months' period has elapsed, giving, (i) Causes and natures, (2) locality and time of day, (3) extent and particulars. IV. — GENERAL DUTIES OF A RAILWAY COMPANY TO THE PEOPLE AND THE RIGHTS OF INDIVIDUALS. (rt) A company may not obstruct the entrance to a mine, open or about to be opened. (6) A company shall not impede navigation in a navigable river. (c) In Constructing drawbridges, bridge-piers or wharves, the manner of construction as it affects navig- able waters shall be fully and entirely decided upon and directed by the Railway Committee, under heavy penal- ties for disobedience. (rf) Highway crossings. I. A railway shall not be carried along a highway, but shall merely cross it, unless permission has been ob- tained from the Railway Committee, and, in crossing a highway, a good safe passage for vehicles must be kept open continually and no obstruction offered to travel. II. In a level crossing, the surface of the rail must not be more than one inch above or below the general surface of the crossmg. III. When a highway passes under a railway, it must have at least 20 feet clear width and 12 feet clear height, and the gradient of the highway shall not exceed one in twenty, unless originally greater and left undisturbed. IV. When a highway passes over a railway, the approaches shall not have a gradient of more than one in twenty, and must be fenced at least four feet liigh, and the bridges by which these highways are carried over the railway shall have a clear height of seven feet above the highest freight car hauled over the road, and over 14 feet clear width shall be given on approaches and biridge. V. The company shall present to the Railway Com- mittee (which notifies the municipality interested in order that they may oppose by a delegation) a plan and profile of every proposed highway crossing, and the committee will I i6o Railway Engineering. I I i 1; 5 1 then decide whether it is to be changed in any way, or if a level crossing is approved of, whether a gate and watchmen are necessary to public safety, and the decision of the committee regarding details of construction, and also as to apportionment of costs between the company and other parties interested, is to be final, and followed out within a prescribed time under penalty. VI. Sign-boards with letters six inches high shall be placed at every highway level crossing. (e) Farm crossings. One, at least, shall be made for every separate por- tion of land and for each disconnected portion thereof, so located as to be difficult of access otherwise than by means of a crossing of the railway. (/) Bridges and tunnels. • Shall be built, maintained (and raised if necessary, whenever repaired or reconstructed), so as to maintain a clear height of seven feet between the top of the highest freight car used and lowest beam or obstruction of the bridge or tunnel. N. B. — The Governor-in- Council may except from this clause any railway on which air brakes are used exclusively. No company shall run cars over any bridge unless constructed and maintained with safeguards, and of strength approved of by the Minister. (g') lences and cattle-guards. Whenever municipalities are surveyed or settlement exists, fences and cattle-guards shall be built and main- tained, and in case of adjacent land being occupied, this must be done as fast as rails are laid, and the company shall provide gates having proper fastenings or hurdles at all farm crossings. When this is done, it is the duty of the landowner to keep the gates closed when not in use. If left open accidentally, no action for damages against the company can be sustained, and if left open purposely, a counter-claim for damage may be entered in addition to inability of recovering for loss of animals, etc., resulting from such leaving open of gates, etc. (Fences must be turned in to the cattle-guards). (/t) Opening of the railway for traffic. . ; - L^ IM T ( H C4 A-t , I ii t 'V A ' Kailway Enginkkring. if.T No company shall open its road for passenger traffic until one month after giving notice in writing to the Min- ister, and after an inspecting engineer sent by the Govern- ment shall have reported favorably as to thf; safety of the road, strength of structures, and adequacy of rolling stock. (i) Repairs. Upon complaint of the officers of any mtinicipality, the Government shall send an inspecting engineer to examine the condition of the road, and the company shall at once make such repairs as he considers necessary fjr public safety. Until such repairs are made the engineer may limit the number, speed or weight of trains and engines passing the point under repair. [j) No discrimination in tolls between diflferent per- sons or companies for the same service shall be allowed ; any special rate allowed to one must be allowed to all. {k) No secret special rebate or toll shall be allowed, and any company shall on demand make known to any- one any special rate, toll or rebate. (/) No discrimination between places shall be allowed, unless a lesser rate is necessary to secure freight at a com- peting point. (This, therefore, protects local points only against one another, and not against railway centres). (m) Every company shall afford full and equal advan- tages to all persons wishing to ship or travel over their railway, and shall afford equal facilities to each and every connecting line or lines of railway for transfer of traffic. (;/) Every company afllordmg facilities to any express company shall grant the same to any other express com- pany demanding it. (o) Every agent of the company shall receive freight or any allowable traffic when offered for shipment, under penalty. (/>) Every train before crossing a draw or swing bridge shall stop at least one minute to ascertain from the bridge tender that the bridge is closed and safe to cross. {q) At least 80 rods before crossing every highway (on level) a bell must be rung or whistle sounded, and this must be continued at short intervals until the crossing is passed. >^!j 1 62 Railway Enginekring. \ 1 ! :i (r) An officer shall be stationed at every level crossing of two railways, and no train shall pass over it until a signal lias been made to the conductor that the way is clear. (s) Every train shall stop one minute at a level rail- way crossing as in No. i6, unless there is an interlocking system, when they may pass at such speed as the commit- tee may allow. (/) No train shall pass through thickly populated towns, etc., at more than six miles per hour, unless the track is fenced. Ah'^I^ ^<^*'i ^i^fi .- <^^ c^ ui (m) No train or car shall be allowed to stand on a highway crossing more than five minutes at a time. (v) All frogs, wing rails, guard rails, etc., shall be packed up to the underside of the rail wherever less than five inches space exists. cf'tC^i^C' U.^ r«if,'ttti k- '• (w) Sections (/>), (r) and (s) 1 e been recently modi- fied so as to permit of interlocking signals being intro- duced at junctions and railway crossings, in which case the Privy Council may permit trains to pass in or across at specified rates of speed without stopping, whenever the signals give the right to do so, but if the signals are not satisfactorily worked the council may revoke the per- mission. V • ■U Raiiavay Engineering. i6s PART II— CHAPTER I. Track. ARTICLE I. — FORM OF ROADBED. The first essential of a good track is proper drainage ; there can hardly be good track without it, from which it naturally follows that too much care cannot be taken in forming a roadbed at the completion of its construction, which will have good drainage in itself; even with abundant and good ballast, drainage is necessary, while it may be the saving feature of a track surfaced with inferior or scanty ballast. Plate XXII. shows types of road- beds in use in America, and it will be seen that most of them have a slight slope each way from thect tre, forming a rounded surface onto which the ballast is laid ; the crown at sub-grade should be 3 to 4 inches for a single track in cutting, but may be partially omitted on embankments, as future settlement tends to round off the corners and aid drainage. Should low spots exist in the centre of the roadbed beneath the ballast, water will lodge there and soften up the earth so that the ties will sink under the churning action of car and engine wheels. Although not essential or always done, it is an advantage and an economy of ballast to elevate the roadbed on curves parallel to the expected plane of the ties and rails ; this practice also gives an elevated track before ballasting is commenced. Widths of roadbed vary with the climate and materials. Embankments vary from 10 feet for cheaply built roads in the Southern U.S.A. to an ordinary standard of 16 feet for Canadian and Northern US. A. first-class roads ; cuttinr'" vary similarly, but are usually about 6 feet wider tha. -! embankments for making ditches ; for purposes of uandling snow it is not found advisable to make cuttings less than 22 feet in Canada, 13 f^ ':• ^ ! 164 Railway Enoinerring. although rock cuts with narrow ditches are sometimes made 20 feet. To all of these, 12 to 14 feet are added for each additional track, and in case of very wet cuttings extra width may be needed for proper drainage (see Fig. 8, Plate XXII.), or a tile may be laid beneath the cut ditches to drain the subsoil (see Fig. 5, Plate XXII.). Ordi- nary cut ditches are about three feet wide and one foot deep, and may be wedge-shaped (Fig. 7) or trough-shaped (Fig. 8), but although the latter is often dug in the first place, the weight of evidence is in favor of the former, which is formed by a flat slope of from 2 to i to 6 to i, starting from near the edge of the ballast and meeting the cut slope at an angle. The tendency of such a ditch is to direct the water well away from the track and thus pre- vent undermining of the ballast. Cut ditches should be led well away from the mouth of the cuttings to avoid scouring the foot of the adjacent bank, indeed, the cut ditch on the upper side should join the catchwater ditch and contitiue down to the entrance of the nearest culvert as a berme ditch placed five or six feet away from the foot of the bank. By a thorough system of ditching at the con- clusion of constru' lion much trouble and expense can be avoided and the energies of the track gangs during early maintenance may then be devoted to other things. To make the ditching system complete, catchwater ditches should be dug along the upper side of every cut, placed six or eight feet back from the top of the slope, the earth from them being placed inside ; these ditches should collect all those small trickling streams and general hillside wash that would otherwise run down the cut slopes, carrying sediment into the cut ditches. These cut ditches are often soon neglected during early maintenance, and extra ties, heaps of unused ballast and stray boulders block the drain- age, while in later years rotten ties and weeds need watch- ing. Too great stress cannot be laid on having clean, r,traight cut ditches with a uniform fall. Of late years construction has been usually very rapid, and embankments, if made of earth, will rarely have com- pleted more than half of their shrinkage ; this will vary in amount with the method used in building the bank, being greatest when built with wheelbarrows or machine graders from side ditches, and least when flat or wheel-scraper I i': '4 ', Railway Enoinkkking. 165 r "*f''t ■,■'■"<>' ■-•■f-- -^ •'••^ _. ki^.i:ir' i, TTrir a 155 I u*4 m r»Mm»i*r > /«* 6ror»/ on Cufvrs V ^••••-f" •■«■■+•-« e"-»-*o:< PiafeXXII Cro J J • Sec tio ns 0/ ffr. /foac/6ec/6 1 66 Railway Engineering. |:7 1 1 ^ ■ |!i \i t ! I ii!f li! I ii!' work has trampled it in thin layers by the horses' feet, etc. For these reasons all banks made of earth ought to be left full width and a certain per cent, of height at each point above the theoretical grade line. Of course, abrupt changes in track surface are not desirable, even for a short time, and such allowance for shrinkage should be made with judgment according to the merits of the case in hand at each point, bearing in mind what the ballast is costing, ihe expense of re-lifting sunken track and the large amounts of extra high- priced material needed if this allowance for shrinkage is not made before grading is completed ; on page 150 the per cent, of shrinkage of different materials is given, which will serve as a basis for estimating how much extra height should be given to the banks ; if construction has been completed in one season at least one-half these amounts are necessary. ARTICLE 2 — BALLAST. The quantity of ballast used is a purely financial question, and up to a usual limit of 12 inches underneath the ties, the more the better can track be maintained for the same cost ; 12 inches under ties takes about 3,000 cubic yards per mile; 6 inches under ties takes about 1,800 cubic yards, including filling around ties as in Fig. 8, Plate XXII., but with no allowance for sunken banks and extra material. The functions of ballast are : (i) To afford lateral, longitudinal and vertical sup- port to the ties sufficient to keep the track in line and surface without incessant track labor. (2) To carry off all wat'^r as rapidly and thoroughly as possible after rain storms or thaws. (3) By drainage to lessen the action of frost in heaving track during the winter and spring. (4) To give elasticity to the roadbed. The following materials are used more or less exten- sively for ballasting and are given in order of merit as nearly as may be : 't) Broken stone to a 2-inch ring ; coarser underneath. (2) Furnace slag and cmder. (3) Coarse, clean gravel. (4) Broken bricks or any form of very hard burnt clay. It Railway Engineering. 167 (5) Sand not so light as to be easily blown away. (6) Earth, usually compact clay, -eldom loam. Broken stone ballast, although expensive and hard to tamp and surface with, erives the mtost tltorable and satisfactory track with least labor for maintenance ; only roads with heavy tr iffic can afford to have it, as it costs from 75 cents to $1.25 per cubic yard in place. When used, it is generally flush w'th the top of the ties for about i foot beyond their ends, thus giving lateral sup- port, and side slopes rather steep (about i to i). A very finished appearance can be given by laying a margin of stones to line by h-nd, and keeping the rest of tha road- bed, outside, free oi ballast and grass. The slag from blast furnaces, if properly cooled and broken, makes a very good and durable ballast, but its use is eviden'^y limited in area, and the price will vary according to circumstances ; cinder also is a valuable ballast, but limited in quantities. Pro- bably gravel may be looked on as the ballast more gener- ally used in America than all other forms combined, because of its wide distribution and general utility. When clean and fairly free from sand and large boulders, it drains well, surfaces easily, and holds track from all but lateral movement ; in this it is deficient as it will not stand steep enough to admit of the ends of the ties being fully submerged, unless a very wide roadbed is used. (See Figs. 3, 7 and 8, Plate XXII.). The cost of gravel ballast in place varying with length of haul, may be put at 15 cents to 20 cents per cubic yard if loaded with steam shovels from a good pit and unloaded by ploughs, but will run as high as 40 cents when material is manually handled from pits with heavy stripping. In all cases the stripping of pits should be attended to, and all inferior material wasted or put on low or narrow banks. The ballast material should be of a uniform quality, as any patches of loam or clay mean just so many sunken spots in the track. Sand ballast creates dust in summer v/hich injures the rolling stock, does not hold a track well to surface or in line under heavy traffic, and has a tendency to hold water and heave track in the spring ; unless very coarse it is not at all a good investment if other ballast can be obtained. In such situations many roads have resorted to burnt clay 1i« m m i68 Railway Engineering. 1^ f ;iii |i i: or broken brick, but unless well and uniformly burnt, almost to vitrilaction, it is not a very durable material. In mild climates, such as Southern U.S.A., many railways have ballasted with clay taken from ordinary cuts, either from the cut slopes or hauled by train from the nearest point. If the clay is of a compact nature, and such a cross- section as one of those in Fig. 6, Plate XXII. is used, it will soon get beaten down and shed ordinary rains without any water permeating the roadbed. It is evidently a very ;,li;j.'?' way to ballast, and in the absence of other cheap ;na trials may be very justifiably used in such climates by roads of light traffic and meagre resources. Except in the case of broken stone, laid with teams, from adjacent fields, the ballast is put on, after the track is laid, by train loads, and, in so doing, unless the newly laid track is at once roughly surfaced, and trains run very slowly over it until a light •* lift " is first put on and the track fairly well lined and surfaced before the ballast trains are allowed to run at a high speed, we may expect permanent injury in the form of bent rails and cracked angle bars, especially as the track is often not fully tied, spiked or bolted. In surfacing and lining track it is well to remember some general principles applicable to all materials and at all times. (a) The coarser material available ought to be put underneath, i.e., on the first lift. (6) When the supply of ballast is limited and sub- grade sunken on the banks, it is better to be satisfied with a trark having local depressions below the theoretical grade line, rather than to rob the sides by building up a high, narrow track to the true grade, as such a track will soon sink .«nd get out of line — bemg deficient in lateral support. (c) Karh tie should be tamped equally well, because even otie tie, without support, acts like a force pump ; each passi/?// truck, by suddenly depressing it, compresses the air atilii i it, forces out more ballast, until there is a cavity ^ofmed, a lodging place for water and a permanent sag in ^he taii. (d) Ballast should be tamped more firmly under the rails than under the centre of the track, because a centre Railway Engineering. 169 bearing will cause a rocking motion which will increase rapidly, especially on banks, where the sides are apt to sink more than the centre anyway. (e) Surface is rather more important than alignment, although not so easily obtained or seen by a track foreman. ARTICLE 3. TIES. Ultimately we may expect metal ties to take the pkce of wooden ones. In Europe, with dear wood and heavy traffic, substantial progress has already been made. In America experimental pieces of track have proven satis- factory in cheapening maintenance, and for many reasons, to be enumerated, we may expect progress to be consider- able in the near future, but for many years wooden ties will continue, oj this continent, to be the rule, and metal ones the exception, although their use constitutes a heavy drain on our forests, which probably amounts to six or seven million ties per year for Canada alone. Wooden Ties. — Wooden ties are in general use because they are cheap, and simple in use or renewal, and by the use of preservatives thtir life may be increased consider- ably. In Belgium and adjacent countries where mild steel ties are in use, wooden ties are being abandoned in favor of steel ones on the following grounds: (i) That their price will gradually rise owing to the devastation of forests. (2) The quality of even the best varieties of wood is variable and an unknown factor, being affected by time of felling, place of growth, seasoning, etc. (3) Preservative methods fail to produce a uniform material for use. (4) No timber merchant will guarantee ties of wood, while two-year guarantees can be obtained for steel ties. (5) There is a loss of interest, due to stacking wooden ties for seasoning, whereas steel ties may be in use, legiti- mately, even before being paid for. (6) The difficulty of obtaining a good fastening of the rail to wooden ties, and the constant rc-spiking necessary. (7) The selling price of old wooden ties is less than metal ones even in proportion to their first cost. All of these objections are more ar less valid, even in America, lyo Railway it^NGiNEERiNt. ( ■ r ! i; ■ - V ik iji, 'i hut the lasting and holding qualities are most MpwflMF/ Ties are ordinarily 8 ft. to 8 ft. 6 inches long, 6 to y inches thick, and 6 to 9 inches wide ^ Co ^ \ 's \ ^* "^ ts ;i |:.i i> I Ji ' n\ . 1 » • 1 ; ■ 174 Railway Engineering. tie at the present time. The increase in the life of ties in irack is greatest amongst soft woods according to the following table : Duration in track. Timber. Untreated. Creosoted. Oak 13 ig Pine 7 15 Fir (Spruce) 5 y Beech 3 16 Creosoted ties will not resist the cutting of rails more, nor are they stronger than untreated ones, but, especially in thickly settled countries, discarded ones will be more valuable as fence posts or fuel, being worth from ^ to ^^ of first cost. Creosoting does not assist ties to hold spikes, and in this respect wooden ties are deficient. Spikes with hard- wood ties on roads of moderate traffic are one thing, with soft-wood ties or with any tie on heavy traffic roads are another. As they are continually being pulled loose by the action of passing trains, and have to be redriven, in the future, with heavier traffic, rails and engines, some- thing must be done to remedy this weakness of American track, the solution of which will lie along two lines, either metal ties and appropriate fastenings, or oak or other durable ties along with tie plates, and fang bolts or wood screws as fastenings — either method will allow deeper rails to be used, or ties spaced farther apart. Metal Ties. — Three types of metal rail-supports are used : (i) Longitudinal flanged sleepers giving a continuous support to the rail, and held to gauge transversely by rods ; sections of these are shown on Plate XXV. (a) and (b) ; they have never come into anything like general use. (2) A succession of cast iron inverted pots, filled inside with ballast and connected, transversely by rods, as in class (i) ; this method has been used in regions of brackish soils where cast iron rusts less than steel, and can be made heavier, as it is a cheaper material ; this method is also only in limited use. (3) Metal cross ties of inverted trough sections are steadil)' increasing in favor and are likely to obtain, in the future, general adoption. Railway Engineering. 175 The tendency of metal cross-ties is to decrease mainten- ance charges year by year, while with wooden ones, especially on curves, the reverse is the case. Of these the Post tie seems to be the favorite in Europe ; on the Netherlands railway, maintenance with metal ties was about one half of what it was with oak ones, with thirty trains per day and engines of fifty tons, and no ties reported broken. A sketch of this tie is given on Plate XXV. (c) ; it is of mild steel, weighing no to 120 lbs. each, and costing a few years ago .$22 to $26 per short ton, with two-year guarantee. It is closed at the ends, narrow and deep at the middle, with thickness varying, being greatest at rail seats ; the bottom edges are in the form of ribs ^ inch thick, projecting i inch. The general thickness is |^ to ^ inch. The narrowing in and deepening at middle gives transverse strength, and prevents the track from creeping longitudinally, or forming a hog back at the centre. The rails are fastened by bolts with T heads and eccentric necks. These bolts pass through the tie from underneath, and into a crab washer which bears on the rail flange and tie ; a Verona nut-lock and a nut complete the fastening, and an oblong hole through the ties allows adjustment on curves. This tie presents economy of material and main- tenance and general efficiency. It has been in long, extensive use in Belgium, Holland and France, and is probably the best metal tie yet devised for flanged rails. In the United States the Hartford tie has been used with good results on the New York Central, and it appears in general to be an imitation of the Post tie, with an endeavor to simplify manufacture, see (d) Plate XXV. Other forms of less tried qualities are the Standard, an inverted channel beam, and the International, having a section like an elongated bracket . '^^ ., which would appear to be deficient in vertical stiffness. It is probable that persistent attempts at improvement will have a tendency to cheapen manufacture, and hasten the introduction of metal ties on many progressive railways having heavy traffic. V. ARTICLE 4. — RAILS. The progressive history of rails from the first longitu- dinal wooden sleepers up to the present would be interest - m |l-! 176 Railway liNciiNEERiNc. ing but not in place here. We have arrived at two types, one used in England and Scotland, and in some British colonies and dependencies, etc.,, ie, the bullhead or double-headed rail, resting in cast-iron chairs, the other used in the world generally, otherwise, (i.e)., the Viguoles or flanged rail, which is self-supporting. (A) Plate XXIII. gives sections of bullhead rails, and on Plate XXV. is shown a cast-iron chair for fastening the rail to the ties, and which adds $1,500 to $2,000 per mile to the cost of the track. The original idea involved in the use of this section was to obtain a reversible rail which would double the wearing value if it could be turned over and used again after one head had worn down, but when it was found that the chairs damaged the rail so that they could not be reversed advantageously, this idea was abandoned, and the section now used has a much larger per cent, of metal in the head than in the base of the rail. The British railways use rather heavy rails considering the light rolling stock, but space their ties 2 feet 6 inches apart, centres, due to the superior supporting quali- ties of the cast-iron chairs ; and, in general, the tracks are very solid and first-class, the rails being held to the chair- seats by long tapering oak keys which are tightened occasionally, while the chairs themselves are fastened to the ties with wood screws and bolts, and even those few British or Irish roads which use flanged rails use the same fastenings with tie plates, not trusting to spikes except at every other tie at the most. A special advantage in using rail chairs is that creosoted pine ties become available, and they are probably the most durable and economical tie in use, where it becomes possible to fasten the track securely to them. {B) Flanged Rails. — The objections urged against flanged rails, that they cut into the ties, and that they cannot be held properly for heavy traffic with spikes, are overcome by adopting tie plates and screws or bolts for fastenings, and the 'dea that they are not rigid on curves is shown to be erroneous, as witness the very heavy engines of America running at high speed around much sharper curves than are used in England. Ka I LVVAV Esc, I N l; KU I Nd. 177 Sfee/ 7/os f6t Caritf^ ont/ ^a// rasteninps etc ^ "«// scat ^^^ _ ^ecno,, I..- I.. I Srifisff f^oi/C/io/f oftd ^»y fd) /^ortford T/e 7'y/aea o-f Stw/ /lo/'/tvoy 7"/>* lii:!! :.!l «F IMAGE EVALUATION TEST TARGET (MT-3) /y ^^ ^ ^ 1.0 I.I m ■■■ "• 1*0 IIO IL25 iu M I 1.6 6" FhoiQgFaphic Sdeices Corparation 23 WBT MAM STRHT WnsnR,N.Y. 14310 (716)t79-49U3 f ^ 178 Railway Engineering. .'*! ( Plates XXIII. and XXIV. give sections of flanged rails of various designs and origins. In detail they will be found to vary widely, but with the exception of the. New York Central rail, which has a narrower base for use with tie plates or steel ties, the height is usually equal to the width of base. The first difference noticeable is the per cent, of metal in the head. Other things equal, the more metal in the head the more wear will be obtained, but rails with relatively heavy heads never cool equally, causing initial strains in the section, and a deep heavy head will not get well rolled, and being spongy will wear rapidly when the top byer is gone. The endeavor now is to get a rail as hard as possible, chemically, that will stand drop tests, with a wide, moderately deep head, but not so deep as to induce sponginess in the centre of the head. A wide head is necessary with modern heavy engines to prevent undue crushing of the top surface, due to heavy concentrated wheel loads, and this forces a small propor- tionate depth of head to keep the per cent, of metal in the rail head from being excessive. Striking differences in rail design occur in the radius of the top of the head, the upper head corners, and in the side slopes of the head. The tendency in America is toward a flat top, shaip corners, and vertical sides, which is the reverse of English practice of round tops, easy corners and sloping sides, while fishing angles are getting flatter and tend to become standard at 13°. Plate XXV. gives a standard U. S. wheel tread — rails after eleven years' wear on curves, and two drawings which contrast the fit of a wheel on a rail head of sharp corner radii with that on one of larger radii. It will be seen by the dotted lines that normal wear is upward and outward, thereby increasing the arc of contact between wheel and rail, thus also increasing the resistance and wear, so that the longer this can be deferred by starting with a sharp corner radius and vertical sides, the better, as the contact is then a roUing one only, and the wear and resistance small. Note that the radii of worn rail corners is still about i inch, and investigation has shown that sharp radii of upper corners of rail heads do not cause sharp flanges on wheels, which has been the chief objection raised against them in the past. Railway Engineering. 179 Composition of Rails. — When steel began to replace iron as a material for rails it was found necessary to remove the notches in the flanges from the centre to the ends, and even omit them altogether to prevent breakage^ the notches being put in the flanges of the angle bars instead, so as to prevent creeping of the track. Rails were made hard to stand wear. Then drop tests were introduced to detect brittleness, and soon forced soft rails to be used, but going to the other extreme the rail heads wore out very quickly, especially as the demand for cheap- ness produced insufficiently rolled rails. Now there is a gradual tendency to get as hard a rail, chemically, as will just stand the drop tests. specifications for Chemical Composition of Rails : (i) Sand berg (Sweden) — Carbon, if alone, |*|yp.c.,but only ^jf p.c. in presence of y\f p.c. phosphorus ; silicon, at least ^\f p.c. to give sound ingot and make rail wear. (2) G. T. R. (Canada) — Carbon, ^^ to ^jf p.c, sulphur, j^jf p.c. or less, phosphorus, ^^^ or less, silicon, ^\f p.c, manganese, ^jg p.c. (3) New York Central Railway (Dudley) — 60 to 70 lb. rail : Carbon, ^jf to y^ p.c, manganese, -^ to 1 p.c, silicon, iV to iVV V-^-' sulphur, ^^^ p.c. or less, phos- phorus j^u p.c. or less ; 70 to 80 lb. rail : Carbon, -^ to ^ p.c, manganese, -^^ to i p.c, silicon, ^^ to fVir P'^'> sulphur, ^^ p.c or less, phosphorus, yg^ p.c. or less ; 100 lb. rail: Carbon, j^^to j^^ p.c, manganese, -^^if to I p.c, silicon, -fV ^^ tott P'^-> sulphur, ^^ p.c. or less, phosphorus, |^ p.c. or less. Dudley, also regarding different constituents that affect the quality of rails, says : Manganese takes up the oxide of iron, and prevents red shortness, but over i p.c. makes rails not only hard but coarsely crystalline, with a tendency to brittleness, flowing easily under wear and oxidizing rapidly in tunnels. Silicon produces solid ingots, free from blow holes in columnar structure, with small compact crystallization. Sulphur causes red shortness and seamy heads ; it also tends to check welding of blow holes and ingot pipes. Phosphorus increases the size of crystals and produces brittleness ; it must therefore be very low in high carbon rails, which make prices higher, as most ores have phosphorus.in them. 14 i8o Railway Engineering. !;;. Physical Drop Tests for Rails : (i) Intercolonial Railway of Canada — Supports 3 ft. 6 inches apart ; a rail 12 ft. long is to stand one blow of 2,000 lbs. falling 18 ft., and three blows falling 6 feet for 67 lb. rail, with a deflection of 3 to 3^ inches for first, and 2i to 3^ inches for second case. (Drop tests for U. S. roads about the same.) (2) Irish Flange Rails.— (a) Supports 3 ft. 6 inches apart, a rail not to deflect more than finch with permanent set not more than | inch for 30,000 lbs. at centre for 30 minutes, (b) Same supports, rail to stand 2 blows without breaking, and not to deflect more than i inch for 2,000 lbs. falling 8 feet. Under wear the top surface of a rail head gets more or less cold-rolled and brittle for about 7*7 inch, which is the cause of heads breaking downwards (e.g.) a broken wheel may hammer and cause the brittle layer at top to crack, and the crack will continue on down until the rail breaks. High stiff rails with a broad head are more needed as the wheel loads on drivers get greater, so fts to keep a decent track and prevent cold rolling. (Large drivers are not so hard as small ones on track.) The endeavor is to get a high carbon rail and work it until it is tough and compact in texture in the head. ARTICLE «;. — RAIL JOINTS. While great progress ha$ beeti made in the strength and rigidity of rail joints, they can hardly be cofisideted yet equal to the critedoKt of simplicity, and of beiftg as Stroi^ as the rail it^f, and as stiff laterally. Sandberg» by watching the effect of trains on itairow notches cut in the heads of B6lid rails, concluded that the l^ipping down was du^ to lack of support of the fibres, and that we may, therefore, not expett to ever obtain a joint so perfect as to prevent this wear entirely. Various joiiats are shown on Pkte XXVI., and kino special ones ftttmched to rails on Plates XXIII. an^ XXIV. Of these the simple fish plates were considered sufhv^.iettt in early railroad da^, whan Wheel loads were light and speeds not excessive, bat, as these increased, the joints could not be kept in swfatce, and a l^wer flange was added, giving <06 «fae aiig*le baa:. If Railway Engineering. i8[ Stcft'enc-tf Sue; ^n^/eBorj /of^m. See C.£ ^/ateXXVJ ftallJo/nts Conf/nuout '^ot/-^nt -mn ':\'' i; I i ■3 Hi i ,l82 Railway Engineering. which is the ordinary standard form to-day. It is simple, easily attached, etc., and may be used as a suspended joint on two ties with four bolts, or a longer one (44 inches), with 6 bolts, is often used, resting on three ties, and although more expensive, gives better results. A comparison was made in Sweden between : (i) Fish plates with Ellsworth base plate. (2) Angle bars. (3) Double deep angle bars with 2-inch extension downward between the ties. The renewals for flattened ends in five years were (i) 6-1^ p.c, (2) i4j*, p.c, (3) xy^jf p.c, but as for stiffness they were (i) ^, (2) J, (3) i. So that Nos. (2) and (3) were considered superior, particularly owing to their simplicity, but as No. 3 was easily heaved by frost and snow it was considered suitable for milder climates, and the choice rested on the angle bars. The Fisher bridge joint has been tested quite exten- sively, and is found to be very stiff vertically, but weak laterally, and its various parts are rather expensive and more complicated than the angle bars. For these reasons it is not likely to find extensive favor. The Churchill joint of N. & W. R. R. is probably the most efficient joint yet designed as far as stiffness, etc., and is ' intended for use with 60 ft. rails. Otherwise it would be too expensive and complicated for ordinary use. The other joints shown appear to have good points, but are of less tried merit. (Also see Engineering News, page 178, Vol. I., 1891, for Paterson rail joint.) We may expect, ultimately, to obtain a joint as strong as the rail itself, but how simple it can be made is for the future to show. ARTICLE 6. — RAIL FIXTURES, ETC. The weak spot of our track is its attachment to the ties by ordinary track spikes. Their heads are often cracked by excessive driving, re-spiking is frequent, and the ties get split and rotten much sooner than they would naturally, and while Greer, Goldie, curved, interlocking and other special spikes are improvements on the dog spike, yet the final solution would seem to be in some Railway Engineering. 183 positive fastening such as wood screws or fang bolts, such as are used to hold rail chairs to the ties on British roads, and while tie plates and selected oak ties are keeping off the evil day, yet as speeds get higher and engines heavier, demanding a high stiff rail, this must be done by heavy traffic roads sooner or later, either with wooden ties and tie-plates, or with steel ties and bolts. Tie plates (such as Goldie,,Servis, Standard, Sand- berg, etc.) will enable roads even with heavy traffic to use soft wood ties and a high stiff rail with narrow base (see N. Y. C. & H. R. R. R. section), and will prolong the life of ties. They are being adopted rapidly, some roads using them on curves only, others for the whole track. Wood screws for holding track are of steel, seven inches long, with thread for 4^ inches, f inch diameter, and have a pulling resistance of about six tons. Fang bolts are attached by boring holes through the ties, and screwing the bolts, which have heads on them suitable for holding down a rail, into a nut, with a fang on it. This fang grips into the wood on the under side of the tie, which prevents it turning or loosening. The vibration caused by passing trains would soon loosen the ordinary nut on the bolts which fasten the angle bar joint to the rails, and, in order to prevent this, many devices have been tried. The double nut is not effective. A gravity lock outside the ordinary nut in the form of an eccentric nut is much better, and Young's patent has been used quite extensively, but the spring nut lock, which consists of one turn or a little more, of a strong steel spiral, with two cutting lips taking hold of angle bar and nut as the nut is screwed on, on top of the nut-lock, is the kind generally used, and being simple, cheap and effective, is likely to remain the favorite kind in use. '•\i ARTICLE 7. — SWITCHES AND FROGS. Outlines of various designs for passing a train from one track to another are given on plate XXVII., but of course there are various forms of attachments differing in detail only. (i) The Stub switch consists of two movable rails, A B, with the ends B supported, and free to slide on i84 Railway Engineering, plates for a lateral distance of five inches, called *' throw." These switch rails or points are from lo to 25 feet long, depending on the frog distance, B C, and the angle of the frog C. The guard rails, D D, prevent derailment at the throat of the frog. The stub switch works for a three- throw as easily as for a two-throw turnout, and can be made into a safety switch (see Cook Switch, Plate XXVII., and Dunn Switch, Engineering News, Vol. II., 1890, page 1 74), and is considered to he more durable and easily kept in working order with snow and ic3 than are the many forms of split rail switches. (2) Dooley's stub switch is a modification which makes easier riding by having one point longer than the other, substituting two jolts for one severer one, but it is not as rigid as the ordinary stub switch. (3) Nicoll half-safety switch is a compromise between the stub switch and a split or Lorenz switch. It is not at all a strong or secure switch, as the two rails are not opposite each other. Its advantages are not very obvious (4) Lorenz safety switch is the model of various split switches. Both rails are feathered down so as to fit close up against solid rails. One is a main line rail, the other for the siding, connected so as to act together. This switch is adapted to position where the traffic is consider- able on the branch line, or turnout, and in climates not troubled with ice or snow, but the split rails or points wear out rapidly, and it is more complicated when applied to three-throw turnouts, necessitating two sets of switch rails, stands, etc., set one ahead of the other, in which case neither of the main line rails are solid. The Stewart switch {Engineering News, Vol. I., 1895, page 59) has a special feature in making the switch rails by bending over solid-headed rails, instead of planing them down to a point. It is claimed this will give durability and rigidity. (5) Ainsworth safety switch is made by giving the solid siding rail a sharp bend or recess, and the corre- sponding switch rail is left square ended, thus providing a more solid track for the main line, and a more durable switch rail. This form is adapted to branch lines having little traffic. Railway Engineering. 185 /^/aFe XX\// TurnouA :S) /f/>?j/»-o/-//> 03 Se*/"*^ h \ 111 m 1 86 Railway Engineering. (6) Wharton safety switch is used for heavy main Hne traffic. It gives a solid main track. The siding rails lead the wheels onto blocks (a.b.) higher than the main line rails, and fall down on to the main line, while in facing the switch the wheels are first lifted by the blocks (a.b.) and then carried over the main line rails by the wheel tread riding on the high rail D. The Macpherson switch (Plate XXVIII.) is a modified Wharton coming into use on the Can. Pac. Ry. The main line is solid, ana the train is thrown onto the siding by having the outside provable rail higher than the main line, and a movable guard rail which is also higher than the main line, but which is thrown into position only when the switch is set for the siding. This design also includes a special form of frog, which is a sliding plate brought into position by means of bell-crank levers and rods operated from the switch stand, when set for siding ; when set for main line the plate is clear of the main line, leaving the main line solid at this point also. This design has been in use since 1892, and it has proven itself very satisfactory and durable. (7) The Themeyer safety switch has one movable split rail, and a stationary split rail or half-frog and guard rail. The movable rail and guard rail guide the wheels onto the siding when set for it. It is successfully used on the B. & O. R. R. The main object of safety switches is to make it safe for a train to trail through a switch from the siding, when it is set for the main line, or vice versa, and this is accom- plished, with split switches, by using springs which allow the movable rails to be forced aside just enough to pass the wheel flanges through. The springs then force the switch points back to the position for which the stand and signal are set. Other special switches of tried merit are the cam automatic, in which the split rails are fixed, and the solid ones move horizontally (see Eng. News, vol. I., 1890, page 489), and the Duggan switch, which has two knuckle- jointed vertical moving split rails. (See Eng. News, vol. I., 1893. page 390.) ys i Railway Engineering. 187 Frogs. — Formerly cast steel solid frogs were common, but as they were more liable to crack, and when worn in one part were unfit for use, they were soon supplanted by frogs made up of pieces of steel rail fitted and bolted together onto a flat steel base plate — any worn part can be easily replaced. Such solid or stiff frogs are in most gen- eral use, but on main lines having heavy traffic, those turnouts with light trafBc are now generally fitted with spring frogs (see Plate XXVIII.) in which either the " point " or the guard rail are movable, and the main line is normally a solid track. A train to or from the siding forces the frog open momentarily, and a spring brings it back again as soon as the train has passed, leav- ing the main line again solid. I'he defect in many of these spring frogs is the tendency to derail wheels with worn treads and flanges, by forcing open the spring frog when a train is on the main line. It is claimed that the Vaughan spring frog, used on the Penn. R. R., overcomes this difHculty by blocking up the tread. Other spring frogs of special features of merit are the Monarch, Ramapo and Pegram, described in the Engineering News since i8go. Turnout Calculations. — The " lead " is the distance KD (Plate XXVIII.) from the switch stand to the frog point. The fixed end of switch rails is the ** heel," and the movable one the •• toe." The " throw " is the amount which the switch stand rod moves the •' toe " of the switch. It is 5 inches for stubs and 3 inches for split switches. ED To designate a frog angle E D F the ratio j^ is called ED the frog number (i.e.) if -pp = 6, then the frog is called a No. 6, the ordinary numbers in use are 8, 9, and 10 for main lines, and 5, 6 and 7 for crowded yards and sidings. The middle frog is a special one, derived from the others by calculation or from a large-scaled plan : (i) To calculate the lead from the frog number we have (see Wicksteed, Trans. C. Soc. C. E.) D M gauge _ . . ., . _. 2 X gauge (Fig. i.) = sin « or approximately A D = sin a but, for small angles sm « frog number = N and gauge = g = 4'75 ft., approximately, then frog distance ss 2.g.N = 9-5 JV (A). n i8H Railway Enginbkking. (a) To find th$ Itugth of the mopohU rails, — Offsets to a circle from a tangent vary as the square ol the distance from tangent point, and taking gauge aa 57 iache^i and throw as 5 inches we have shde rails |_5_ j^ .^. frog dislance * N57 lo '^ ' ^ ' also, for stub switch, lead ■ — frog distance (C) which equations give all necessary data for a simple turnout for a stub switch. The frog for a very short distance is straight, and the slide rail is often practically straight, but by using a long rail and spiking the fixed portion, the movable part will bend to a curve. If split switches are used Fig. 2 will apply, and the movable rail being, necessarily, straight, is from B to C only, is tangent to the circle at B, and is half as long as a stub switch movable rail, also in this case the switch stand is at a different place K. C. and we have Switch rail = i X ,^0 « ,'<, ^^^S distance (D). Lead a frog distance — A C » \l frug distance (£). EXAMPLES. (a) Stub switch No. 8 frog — Frog distance = 8 x 9*5 = 76 feet by {A). Slide rail = ^ x 76 = 22 ,V feet by (B). Lead = 76 - 22-8 = 53 ,»^ feet by (C). (6) Split switch No. 9 frog — Frog distance = 9 x 9*5 =s 85.5 feet by (A). Lead = 4o x 85.5 = 72.6 feet by (E). Slide rail = ,», x 85.5 « 12.9 feet by (D). Note. — These distances can be varied by a small percentage without affecting the running of the trains. (3) Middle frog calculations, Fig. 3, Plate XXVIIL First let the two turnouts AE AF be of same degree of curve a^ start from same switch stand, then AD \i Ti • — -^ a I — or i4 D = -i— i4 C, which gives us the middle AC -^2 100 ^ frog distance from the frog distance AC, which ' ^ jation (^ ) determines. 3S Railway Enginkuring. 189 Piate XXVIII •rr*tltm»-» ««rA«o «•« I go Railway Engineering. *iH Also for small angles the angle of the middle frog will be 2 X -/o^o frog angle at C := 1.42 frog angle C, and the number of the frog will be — x frog number C = 703 1 142 frog number C. Second let the turnouts be of different sharpness, and let one begin say 6 feet ahead of the other, let the right hand turnout start first and be a No. 8 frog, and the left hand one a No. 10 frog. Call the middle frog distance x . The two turnout frog distances are 8 X 9"5 = 76 feet, and 6 + 10 x 9*5 = loi feet. Offset from one tangent to B = [ — X 475 ft. lx-6\9 " " other tangent to B = — x 475 ft. But both offsets added = gauge = 4.75 ft., therefore 475 = 475 and solving this quadratic equation we get x = 61 '6 ft. Also we can determine its lateral position by substituting in either of the above equations this value of ;«;, in this case these are 3.13 ft. and 1.62 ft. The angle of the middle frog, in this case, can be calculated thus : Middle frog angle = — ^ angle of No. 8 frog + :^^ angle of No. 10 frog. 95 ^ In crowded yards and with split switches these con- ditions prevail, and many much more intricate calculations ore often needed when the turnouts are from curves, and cross other tracks which are also curving, but these can often be best obtained by carefully drawn plans to large scale. Railway Engineering. 191 192 Railway Engineering. I;' Railway Enginebring. 193. 194 Railway Engineering. /o /J- so Railway Engineering. 195 0/»£Af Sr-OAfe Ct/i.\/rs De/»/A,tn /»«if Su6-grat!/e 7^ /ou^ttt/cn. 15 196 Railway Engineering. DMemMM or Ct/a.^Td's in SroNe Sox O4/LVTS "fo so 30 ^t-o so O^ptft. in feet ^tM6-grad» /b -foundofi'on. Railway Engineering. 197 so 00 -40 so OepiJi, in feet ^•jh-^r-at/e ^ founefatfoo / > INDEX. ITKM I'A(;KS A Abutments 99, loi, 104, 105 Quantities in 108 I )iagra is of 109 Acreage of watcr.Mieils 75, 76 Adhesion 39 Angle bars i8a Angle bar renewals iHa Arch abutments 98 Arch centres 97, 100 Arch thrusts 98 Areas .75. 76, 144, 145 B Ballast 163, 166, 167 Quantity of 166 Function of 166 Materials 166 Cost of 167 Ballasting 167, 168 Barometer 63, 64 Batter 107, 1 1 1 Bench marks 7? Bents 121, 133 Bogie trucks 4 Bunds 14. 19. 20 Bonuses 14, 20, 21 Borrow pits 148 Braces 123 Brakes 38 Branches 13 Bridges 65, 103 Bridge abutments 104 Bridge piers no, 112 Caissons 136, 137, 139 Capitalization 14, 18, 20, 22 Centre bearing 168 Chairs 176, 177 Cinder ballast 167 Classification 71, 148 Clay ballast 168 Copings 1 10 Corbells 86, 90 Cofferdams 136, 137 Compressed air . . 137, 138, 139, 168 Creosoting 171 , 176 Cross sections 74, 142, 143 Crown of roadbed 163 Culverts — Arch 92, 93, 94. 95 Arch specification 100 Cost of 91 Open 80, 83, 85 ITKM I'A<;ks Stone box 86, 88, 90 Specifications for 90 'linilwr box 84, 87 (Juaiitities in 196, 197 ( ulvert well 86 Curves 47, 176 Curvature 4, 7. 33 Curve compensation 36, 37 ' ' elevation 163 ' ' fornmla* 56 ' ' notes 48 " resistances . .25, 33, 34. 37 178 C!urves, transition 49, 50 " vertical 44 Cuts 163 (!ut ditches 164 Cut waters 113 Composition of rails 179 Cihemical rail composition 179 Churchhill joint 173, 182 Deflections 48, 57, 59, 180 Ditches — Berm 151, 164 Catchwater 151, 164 Clearing of 164 Cut 151, 164 Drainage 75, 151, 163, 164 Dredging, open 141 Drop tests 180 Dudley 179 Earnings 14, 20 Earth ballast 168 Eckel's formula 145 Elevation, track 32, 50 Of roadbed 163 Of trestle floors 126, 127 Elevations 64, 65 Embankments 163 Building of 164, 166 Engines 4, 38 Weight of 38, 40 Mileage of 40 Engine Divisions 9 Engineers i, 44, 46, 51, 65, 66 Estimates 6, 71, 150 Excavations 150 Exploration 63 Fang boks 171. 174, 183 Feeders 13 Indkx. ITKM HA(Jl;s Finances 6 I'isli plates iHo, iHi , i8a l''islier joint iHa Fixed charges 14 Floor systems 134 Foundations. .71, 78, 79, 89, 100, [lao, ia8, 141 Freight 14 Freight rates 5, 14 l-oads 5, 14 Friction " . 35 Frogs 1H4, 187 Solid 187 Spring 187 Middle 1H8 Frog numl)ers 187 (irade line i66 (Jr.ade resistances ... .25, a8, 32 37 Grades 8, 29, 30, 38 44 Diurnid 64 In yards 31 Maximum 4a (iravel 167 (Juard rails 125 H Hartford tie 175, 177 Headwalls 79 Hubs 70, 73 I Iron Viaducts- Weight of 117 Lay out 117 K Keys, oak 176 L Laying out work 14a Lead 187 Levels ' 67, 74 Leveller 69, 72 Lift 168 Loads 38, 129 Long rails 182 M Maps 65 Metal ties 174 Middle frog 188 M Narrow gauge 8 Nutlocks 183 Offsets 48, 56, 73 Open dredging 141 P Parabola 4''> 49> 54 Passengers 13 IIKM I'Ac;ks I'edestaU 1 17, 119 I'icketman 66, 70 Piers, masonry , . 1 10, 112 Metal and concrete 115, 1 16 Piles 81, 120,132, 133 I'ile driving iji, 132 Pipe trenches 78, 70 •''!'«» 77. 79 ( ,'ost of 80 Plank boxes 79 Post tie 175, 177 Preservatives 171 Prismoidal formula 146 '•rejects 5 (Quantities. .108, 138, 146, t92 to 197 Railheads 178 Rail joints 180, 182 Railwear 177, 178 Rails 8, 32, 175 Bullhead 172, 176 Broken 179, 180 Bent 168, 180 Composition of 179 Chairs 176, 177 Flanged 176 Long i8a Impurities in 179 Railway crossings 158 Railway Law 153 Railways, Canadian4, 14,18,24, 191 Rates 14, 10 Freipht 5, 14 Passenger 14 Receipts 18, 42 Rivers 65 Roadbed 163, 165 Width of 163, 164 Routes 9. 42» 63 Ruling grades 41 Sags in grade 31, 168 Sandberg 179, 180 Sand ballast 167 Shrinkage 71,150, 166 Sills 1 19, lao Slag ballast 166, 167 Slopes 142, 152 Slippage 35 Specifications, 90, 100, 1 14, 133, 1 50, 179 Speed 27; 29, 31 , 32, 153, 176 Spikes 170, 174, i8a Spirals 51, 5a Spongy railheads 178 Statistics 10, 11, r4, 191 Stiction 26 Stock 14, 19, 20 Stone ballast 167 Stringers 125 Strippings 167 Substructure 42 Subtangent 47, 49 IT KM Sii|mly shafts Surfiteinj; . , . . Sui vt'vs . . In PA(ii;s Kwonnaissiince , . Isa Tiia Location Switch points Switches StuI) I .orenz . . . Wharton . .6a, .6a, 71 140 16H 6a 66 '57 1H4 «H3 '83 i>44 184 .'|>"K!'"«s la, 48, SQ lerniinnls ;';!« Pliit'-s ■■■'■'■iji'.'iis. lies - Metal Sunken '....!!.. W'ooilen _ _ 'riml)er construction ". Topography 67, 68,' 69' I rack- Moves ... 7, Double ■.■;;. ''' "™vinK '.'.'.'.'.166, Narrow ):P^^^^. "i.'."." '170.' 174,' lainpini- Transit . . . . . .48.' 59, 66V67,' 69, Iransitions .g ''"•■affic 8, 12, 14',' 42' (irowth of o Vohitne of ... . 60 '3 '«3 «74 168 169 .S7 73 79 164 167 1 68 1H2 16H 72 59 191 17 16 "^^ III. • "•'•'^' I'A.JKS I rain loads -o Train resistances . , . ". as 17 Transportation ' , Trestle floors .' ." 8o." i aV. i36 . ''"'^''''''i^'" ia8, i„a ( ost of ' ,jj^ Tnnik lines ...... la 11 Turnouts ' i^e Turnout calculations .!.!.,!] 1 1 187 V Velocity head 7, ao. „ \ laducts , , : , ,_ \'irtual prohlc .........,' 30 W VV'aterwnvs -, ••'ornuiliu for '.'.'.','.'.' -o Wheel treads ... 177 i-h Wlu-el loads •.■.•.■.■.•.•.•.,7'^; \'Z Wind resistance 3- ^^ VVork, laying nut '..'.'.'.'...' ,ja Wooden ties ,^ (Qualities of ,^, Life of .■.■..■.■.',■." ,70 IVescrvation of ' ' ,-3 Kinds of ' ' ^-^ ^y/eoi .'.'.'.'.'" 170 Wood screw ,7,, ,74, ,76 .g Worn rails ,-7 ,„j^ Working chaniljcr ' ,^q Working expenses ..6. y. 14, 17 20