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 ENGINEERING 
 ECONOMICS 
 
 By 
 
 J. A. L. WADDELL. D.Sc..D.E.,LL.D. 
 Consulting Engineer 
 
 ENGINEERING ALUMNI ASSOCIATION 
 
 SCHOOL OP ENGINEERING 
 
 UNIVERSITY OF KANSAS 
 
 LAWRENCE 
 
 1917 
 
 (DISTRIBUTED FROM THE DEAN'S OFFICE) 
 
ENGINEERING 
 ECONOMICS 
 
 A Series of Lectures Delivered Before the 
 
 Students of the University of Kansas, 
 
 School of Engineering 
 
 FEBRUARY 9, 1917 
 
 In Three Parts: 
 
 I. THE GENERAL PROBLEM 
 II. ECONOMICS OF BRIDGES 
 
 III. ECONOMICS OF OTHER ENGINEERING 
 SPECIALTIES 
 
TA 153 
 
 ENGINEERING ECONOMICS 
 LECTURE I 
 
 The subject^of these lectures was not chosen by the speaker, but was 
 allotted to him by your worthy dean of engineering, Prof. P. F. Walker. 
 It is a topic that very few engineers would care to undertake to cover in 
 three short lectures, not only because of its complication but also on 
 account of its vast extent, permeating, as it does, every branch and 
 division of engineering, great and small, and all work that is either directly 
 or indirectly connected with the profession. On that account the speaker 
 debated for some time before accepting the invitation to address you on 
 the specified theme; for he would greatly have preferred to take some 
 subject in which he has really specialized, primarily because he could do 
 himself more credit thereby, but, it must be confessed, also because he 
 rather dreaded the immense amount of preliminary study and research 
 requisite to a proper presentation of the matter. As far as his specialty 
 of bridges is concerned, he is able to treat the question of economics quite 
 readily, because he has been dealing with it and writing about it for more 
 than three decades; but when it comes to discussing economics in other 
 lines of engineering, he feels very much at sea so much so that he im- 
 mediately decided that he would have to divide his discourse under two 
 main headings, viz., general features which pertain to engineering of all 
 kinds, and detailed features relating to the numerous specialties into 
 which during the last half century the profession has been segregated, 
 and also that he would have to seek assistance on the latter. Any engineer 
 of years and wide experience in one or more lines of activity should be 
 capable of handling the first division, but no man, unaided, could ade- 
 quately treat the second division in more than two or three specialties. 
 
 Recognizing this to be the case, the speaker took the liberty of calling 
 to his aid some of the leading specialists and authorities of America so as 
 to supply him with the salient features of economics in design and con- 
 struction in the numerous divisions and subdivisions of engineering prac- 
 tice. Acknowledgment of such aid received is made throughout the text 
 of these addresses, usually by means of foot-notes; but the speaker deems 
 it advisable to state collectively at the outset the names of the gentlemen 
 who have so favored him and their special lines of work. They are as 
 follows, the arrangement of the list being alphabetical in relation to the 
 specialties: 
 
 SPECIALTY AUTHORITY 
 
 City Planning CHAS. MULFORD ROBINSON 
 
 Dams ALFRED D. FLINN 
 
 Electric Railways E. P. ROBERTS 
 
 3 
 
 371590 
 
SPECIALTY AUTHORITY 
 
 Engineering Teaching GEO. F. SWAIN 
 
 Harbors WM. P. ANDERSON 
 
 Highways W. G. HARGER 
 
 Inspection P. S. HILDRETH 
 
 Mining JAS. W. MALCOLMSON 
 
 RaHroadin* 
 
 Water Supply ALFRED D. FLINN 
 
 To all these gentlemen, individually and collectively, the speaker 
 desires herewith to tender his hearty thanks and deep appreciation. 
 Without their valuable aid these lectures on the lines adopted would have 
 been impossible. 
 
 It should be noted that the preceding list of subjects is by no means 
 complete. It is limited by the responses from the "authorities" to the 
 speaker's appeal for aid. On the whole, the profession has been very 
 generous; and while there is evidently a lack of correlation and uniformity 
 in the various treatments, this is unavoidable. Moreover, it should not 
 be objectionable, indicating, as it does very clearly, the personal equations 
 of the donors of the information, notwithstanding the fact that occasion- 
 ally the speaker has taken the liberty of materially modifying the diction. 
 
 Again, the incompleteness of the list of subjects is not a blemish; 
 because, if it had been made even approximately complete, there would 
 not have been sufficient time in the set limit to discuss all the topics with 
 adequate fullness. 
 
 In one sense the subject of economics in engineering is a new one, 
 because it is only of late years that it has been given much attention by 
 designers, builders, and technical writers; but as far as the speaker's task 
 is concerned it may be said to be an old one, for the reason that the said 
 subject has been systematically and elegantly treated by Prof. J. C. L. 
 Fish, of Leland Stanford University, in his excellent little work, which 
 bears the same title as that of these lectures, viz., "Engineering Eco- 
 nomics". Although that work covers the ground in a satisfactory manner, 
 it will not be necessary for the speaker to crib from it; because the subject 
 is such a broad one that it will bear treatment from more than one point 
 of view. 
 
 As far as relates to engineering, the term "Economics" has been defined 
 thus in the "Glossary of Terms" of the speaker's new book on "Bridge 
 Engineering"*, "The science of obtaining a desired result with the 
 ultimate minimum expenditure of effort, money, or material". It is upon 
 the basis of this definition that these lectures are predicated. 
 
 GENERAL FEATURES OP ECONOMICS 
 When determining, from the standpoint of economy, which is the best 
 
 *J. A. L. Waddell, 1916, "Bridge Engineering", Wiley & Sons. 
 
 4 
 
of a number of proposed constructions or machines, one should compute 
 for each case the four following quantities, and their sums: 
 
 A. The annual expense for operation. 
 
 B. The average annual cost of repairs. 
 
 C. The average annual cost of renewals. 
 
 D. The annual interest on the money invested. 
 
 That one for which this sum is least is the most economic of all the 
 proposed constructions or machines; but this statement is truly correct 
 only when the costs of operation, repairs, and renewals are averaged over 
 a long term of years; or else, for a comparatively short period of time, 
 when the conditions in respect to wear and deterioration at the end of 
 that period are practically the same for all cases. 
 
 The principal economic investigation that occurs in engineering practice 
 is that of determining the financial excellence of a proposed enterprise. 
 It consists in showing by proper calculations its first cost, the probable 
 total annual expense of maintenance, repairs, operation, and interest, the 
 advisable allowance for deterioration or ultimate replacement, the prob- 
 able gross income, and the resulting net income that can be used in paying 
 dividends on the stock or other profits to the promoters. Whether any 
 proposed enterprise, after being thus figured, will prove profitable will 
 depend greatly on the state of the money market, the size of the project, 
 the probabilities of future changes in governing conditions, and the per- 
 sonal equation of the investor. Generally speaking, if the computed net 
 annual profits on the total cost of the investment (over and above all 
 expenses of every kind, including maintenance, repairs, operation, sinking 
 fund, and interest on all borrowed capital) do not exceed five (5) per cent 
 of the said total cost, the project is not attractive; if it be as high as ten 
 (10) per cent, the enterprise is deemed ordinarily good; and if it be fifteen 
 (15) per cent or more the scheme is termed "gilt-edged". Small projects 
 necessitate greater probable percentages of net earnings than do large 
 ones; and any possibility of a future reduction of income will call for a high 
 estimate of net earning capacity. Finally, the measure of individual 
 greed on the part of the investor will be found to be an important factor 
 in the determination of the attractiveness of any suggested enterprise. 
 
 Such investigations as the economics of an important project should 
 generally be entrusted only to engineers experienced in the line of activity 
 to which the said project properly belongs; for if they be left to inexper- 
 ienced investigators, it is more than likely that mistakes will be made and 
 money lost in consequence. The professional men who generally do such 
 work are the independent consulting engineers; certain specialists retained 
 on salary solely for this purpose by important organizations, such as rail- 
 road companies; and engineers who are regularly in the employ of large 
 banking houses. The work involved is of such importance that it usually 
 commands large compensation as, indeed, it should; because to do it 
 effectively demands not only long experience but also good judgment and 
 a vast amount of mental labor, both in order to make oneself capable in 
 general and so as to consider thoroughly all the points embraced by the 
 special problem in hand. 
 
 This fundamental economic problem is often one of extreme com plica- 
 
tion, involving, perhaps, a determination of the character of the proposed 
 improvement, a choice of sites or routes, a selection of uses, a considera- 
 tion of aesthetics, an option on type or style of construction, a question of 
 ultimate durability, a study of greatest possible convenience, a prevision 
 of serious opposition, a prognostication of future conditions, an anticipa- 
 tion of prospective structural modifications, and a safe estimate of cost. 
 The best way to illustrate such complication is by presenting a few exam- 
 ples of actual cases, either pending or already solved; and in so doing the 
 speaker hopes that he will be pardoned for selecting them mainly from 
 his own specialty of bridgework and his own personal experience, because 
 he can thus enter more fully into detail and can vouch for the information's 
 being correct. 
 
 CASE I 
 
 There is in contemplation a project for building a long, high, and ex- 
 ceedingly expensive bridge across San Francisco Harbor so as to connect 
 the great city of San Francisco with the cities of Oakland, Berkeley, and 
 its other suburbs. This project has been a dream for at least a decade; 
 but it is not a pipe-dream, because some day in some manner or other it 
 is certain to be realized. Some eight years ago the speaker prepared a 
 report for a banker on the feasibility of the project, the necessity for the 
 structure, the possible revenue from its use, and its approximate cost; 
 and since then several other engineers have made independent studies of 
 the problem. The communities interested, however, have taken as yet 
 no sensible step towards making a thorough study of the question. 
 
 How short sighted most promoters of important projects can be! They 
 imagine they can obtain expert opinion of real value without paying for 
 it; consequently they collect a mass of scattered and divergent information, 
 which, in most cases, is of no earthly use. Any project of importance is, 
 of necessity, a great economic problem, and ought to be solved at the very 
 outset by special engineering talent of the highest order. 
 
 A glaring example of the utter folly of a community in proceeding with 
 important engineering construction without first having a thorough 
 economic study of the problem made by a competent specialist is given 
 in Engineering News of November 30, 1916. It relates to the municipal 
 water-power enterprise on which the city of Montreal has been busy for 
 some years. Feeling that the work was being sadly mismanaged, certain 
 prominent Canadian engineers "butted in", investigated, and reported 
 upon the incomplete project. They showed that the $12,000,000 enter- 
 prise which the city had about half finished will fall so far short of returning 
 a profit on its cost, and that it has so many serious defects, that it will be 
 far better for the community to lose all it has thus far expended than to 
 incur the additional outlay necessary to complete the work. A thorough 
 investigation to determine beforehand whether the scheme would be profit- 
 able would certainly have indicated the futility of constructing on the 
 lines that were adopted. 
 
 But to return to the case of the proposed San Francisco Harbor bridge 
 practically none of the governing conditions are satisfactorily known; 
 and, judging by present indications, it is likely to be a long time before 
 
they will be, unless, perchance, the leading citizens of the various commu- 
 nities concerned bestir themselves and prevail on their ruling bodies to 
 join forces, raise the requisite funds, choose an engineer of national repu- 
 tation (or, preferably, a board of three such engineers), arrange to allow 
 him or them adequate compensation for expert services and all the money 
 necessary for borings and other investigations, accord ample time for the 
 entire work, and thus obtain a report that will settle finally all the import- 
 ant economic and technical points involved in the proposition. 
 
 The main features to determine are as follows, the listing being done 
 according to relative importance: 
 
 FIRST. The probable gross incomes from all practicabl combinations 
 of the various sources, year by year for a long term of years, and the pro- 
 portion thereof that is likely to prove net in each combination. 
 
 SECOND. Based upon the result of this investigation, the determina- 
 tion of the extreme superior limit of cost for the structure for each combi- 
 nation of the different kinds of traffic. 
 
 THIRD. In view of the great depths of water in the harbor, what one 
 or more of the several proposed or possible sites might be utilized for 
 building a bridge within the several ascertained limits of cost. 
 
 FOURTH. Of what kind of traffic it is advisable that the proposed 
 bridge should take care. 
 
 FIFTH. The character of the foundation soil as determined beyond all 
 doubt by making proper borings, and the settlement of best depths for 
 all pier foundations. 
 
 SIXTH. The various requirements of the U. S. Government in respect 
 to minimum span-lengths, vertical clearances, and temporary obstruction 
 of waterway for each proposed crossing. 
 
 SEVENTH. The minimum clear headway which, for a combination of 
 all reasons, it is expedient to adopt for each proposed crossing; and the 
 choice between a bridge with and a bridge without an opening span or 
 opening spans. 
 
 EIGHTH. A safe estimate of total cost of structure for each layout 
 that proves to be feasible, and the corresponding estimates of cost of 
 operation, maintenance, repairs, etc. 
 
 NINTH. The time required for completion of construction of the 
 structure for each feasible layout. 
 
 After all these points have been settled and embodied in a report, it 
 will be easy to determine finally whether, either at the present time or 
 within a certain number of years, it will be feasible or advisable to build 
 the proposed structure; where it should be located; what traffic it should 
 carry; how long it will take to build it; what it will cost for construction, 
 maintenance, and operation; and how the necessary funds are to be 
 provided. 
 
 The actual conditions for the proposed San Francisco Harbor bridge, 
 as well as they can be stated at present, are as follows: 
 
 A. There is a large possible income from passenger traffic, mainly 
 from commuters who now use the ferry, most of which traffic would soon 
 be diverted to the structure, provided that truly-rapid transit thereon 
 
be furnished at all times; and the said income, under present conditions, 
 would be large enough to warrant the building of an open-decked, double- 
 track, electric-railway bridge which would carry no other kind of traffic. 
 
 B. There is a rapidly increasing amount of automobile traffic now cared 
 for by the ferry; and this, undoubtedly, would be augmented materially 
 by the superior and, possibly, cheaper service of the bridge; nevertheless 
 it is doubtful whether it would be large enough to warrant the building 
 of separate passageways with paved floor and the necessarily greater 
 carrying capacity of the trusses. It would be out of the question to let 
 the automobiles use the same space as the electric trains; for such an 
 arrangement would prevent the rapid transit of the latter. 
 
 C. There is an immense amount of freight crossing the water; but, 
 for two reasons, it does not appear probable that it would ever be econom- 
 ical to transport it over a bridge. The first reason is the great height to 
 which both it and its containing vehicles would have to be lifted, and the 
 consequent expense of such lifting. The second is the greatly augmented 
 cost of structure, due to the far larger live loads for both the floor system 
 and the trusses, that the carrying of such freight would necessitate. It 
 would probably be more economical either to transfer the freight by ferry 
 as is done at present, or to carry it by rail around the south end of the Bay. 
 
 D. There is at certain seasons a large amount of passenger traffic to 
 and from San Francisco by certain trans-continental railroads; hence the 
 question arises whether the passengers should be carried across in the 
 steam-railway cars on which they travel or whether they should go over 
 in the electric-railway cars. The objection to the latter method is the 
 individual trouble, inconvenience, and loss of time for each passenger; 
 while the objection to the former is the increased cost of structure due to 
 the difference in the live loads between steam-railway cars and electric- 
 railway cars. Of course, the former would have to be hauled in short 
 trains by electric motors so as to avoid the excessive concentrated loading 
 from the heavy steam-locomotives. 
 
 E. The most direct route for the crossing is from Telegraph Hill to the 
 outer end of Goat Island, and thence to near the Oakland Pier; and this 
 is the one to which, until quite lately, most attention has been paid. The 
 main objections to it are as follows: 
 
 FIRST. The depth of water between the city and Goat Island is ex- 
 cessive, thus making the pier foundations very expensive. 
 
 SECOND. A large proportion of the steamers using the harbor would 
 have to pass under the structure. 
 
 THIRD. The War-Department requirements in respect to both hori- 
 zontal and vertical clearances would be excessive for this location because 
 of the large number of vessels passing; and, in consequence, the cost of 
 structure would be greatly augmented. 
 
 F. By locating further inside the Bay, the depth of water would be 
 reduced to a reasonable amount, and the number of vessels passing the 
 structure would be comparatively small. In fact, the farther back from 
 the harbor-entrance the structure is located, the smaller will be the depth 
 of water and the fewer will be the passing vessels. On the other hand, 
 
 8 
 
though, the greater will be the total length of structure, the farther from 
 the centre of population will be its city end, and the greater will be the 
 distance which the passengers will have to travel. 
 
 G. Practically nothing is known about the characters of foundations 
 that would be encountered at the various proposed locations; and no pro- 
 vision has been made for money to make the necessary borings. 
 
 H. It is impracticable to obtain a final decision concerning required 
 span-lengths until a bonafide design, properly backed, has been presented 
 to the War Department for approval. 
 
 I. In regard to minimum clear-headway, it is probable that the farther 
 inside the harbor the location the less the requirement, because the 
 smaller and less important would be the passing craft, and the fewer the 
 number thereof. Some of them might be forced to lower topgallant 
 masts in order to pass beneath the structure. 
 
 J. There would be a serious objection to any opening span because 
 of the delay which would be involved by its operation. The real raison 
 d'etre of the structure is rapid transit, hence to interfere with it in any 
 way would be highly objectionable. 
 
 K. The total cost of structure would decrease to a certain point as 
 the location is moved up the harbor, because of cheaper foundations and 
 the consequently shorter spans; but beyond the said point it would in- 
 crease because of the greater length of bridge. 
 
 L. The more expensive the structure the longer will be the time re- 
 quired to build it; hence it may be concluded that one of the inner harbor 
 locations would need much less time for completion of bridge than the 
 Goat-Island layout. This matter of time for completion of structure 
 possesses a double importance, because any delay increases the item of 
 cost due to interest during construction; and by postponing the inception 
 of operation it involves a loss of income from use. 
 
 From the preceding it is evident that the solution of the initial economic 
 problem in connection with the proposed San Francisco Harbor bridge 
 is one of considerable complication. 
 
 CASE II 
 
 The City of New Orleans for many years has had under consideration 
 the building of a combined railway and highway bridge across the Missis- 
 sippi River; and within the last year the project has been seriously con- 
 templated. 
 
 Nearly two decades ago the late Collis P. Huntington, President of the 
 Southern Pacific Railway Company, and his consulting engineer, the late 
 Dr. Elmer L. Corthell, made an investigation of the scheme of building 
 at that place a double-track railway bridge; and they called in as advisory 
 engineers the speaker and his brother, Montgomery, to estimate upon the 
 cost of a low bridge. The death of Mr. Huntington, which occurred 
 shortly afterwards, caused the project to be dropped; and it was never 
 revived. The speaker's study was made with considerable thoroughness. 
 It involved the solution of two or three problems of great magnitude 
 which were new to the engineering profession, the principal economic one 
 
 9 
 
being a comparison of costs of a high bridge and a low bridge. The result 
 was decidedly in favor of the latter. 
 
 The problem now facing the City, however, is much more complicated, 
 involving, as it does, a combination of steam-railway, electric-railway, 
 vehicular, and pedestrian traffics. There is a choice between two locations, 
 one near the centre of the city and the other several miles further up- 
 stream in fact, some intermediate locations might have to be considered. 
 There is a sentiment among certain prominent citizens favoring a tunnel 
 rather than a bridge; and, on that account, the question of bridge versus 
 tunnel will have to be considered, notwithstanding the fact that the diffi- 
 culties presented by the tunnel proposition are almost insurmountable 
 in view of the present status of engineering knowledge and experience. 
 
 The question of high-bridge versus low-bridge will have to be thoroughly 
 thrashed out in order to please the populace, although any truly-exper- 
 ienced engineer would determine very quickly in favor of the latter, 
 irrespective of the possible opposition of the river interests and even that 
 of the War Department. 
 
 The economic method of handling the combination of the various 
 kinds of traffic would require some study to determine; and the best 
 method might vary with the location of the structure. 
 
 The style and dimensions of the moving span whether swing, bascule, 
 or vertical lift and the sizes of the clear opening or openings are mooted 
 points involving a consideration of economics and other important matters. 
 This question is complicated by the fact that the requirements ought to 
 be dependent on the location; because at the upper one there would be 
 very few vessels passing, while at the lower one there would be many. 
 
 The unprecedented depth for the pier foundations involves an economic 
 study in order to ascertain the best method of sinking and founding. 
 
 The facilities for freight, passenger, and vehicular traffic afforded by 
 the several proposed crossings would affect the total earnings of the struc- 
 ture; hence this feature should receive special attention. 
 
 The grade and alignment for any proposed crossing are factors that 
 must be included in the economic study, because they affect the cost of 
 handling the traffic; and the matter of right-of-way may prove an import- 
 ant consideration. 
 
 The property damages involved by the approaches to the structure and 
 the shifting of existing tracks would differ materially in cost at the various 
 possible crossings, hence this feature is one involving economics. 
 
 The choice between single-deck and double-deck spans entails a con- 
 sideration of economics that may prove to be of some importance. 
 
 After determining the various kinds of traffic to take care of, there 
 remains the economic problem of deciding upon the live loads for the 
 various parts of the structure. If these are made too high, there is a 
 waste of material involved, and the bridge enterprise will forever after be 
 burdened with an unnecessarily large annual interest to be paid on that 
 account; but if they are made much too low, the life of the structure will be 
 curtailed. The saving clause, however, in respect to this adjustment is 
 that, ordinarily, a steel bridge does not have to be removed because of 
 
 10 
 
overloading until the metal thereof is actually stressed at least fifty (50) 
 per cent more than the permissible intensities of working stresses given 
 in standard specifications for design. 
 
 This general problem of the proposed New Orleans bridge, while not 
 so complicated as that of the proposed San Francisco-Harbor structure, 
 is of an intricate nature, and will demand for its solution engineering 
 ability and experience of the highest order. 
 
 CASE III 
 
 There is given in the speaker's treatise on "Bridge Engineering" in 
 the Chapter on "Reports", on pp. 1575 to 1581, inclusive, an economic 
 study for the replacement of a bridge over the Mississippi River, which 
 illustrates some of the economic questions that arise in a consulting bridge 
 engineer's practice. In that case the point at issue was whether it would be 
 best to build a single-track or a double-track bridge or to arrange for the 
 conversion at some future time of a single-track structure into a double- 
 track one. Five methods of doing the latter were suggested, and the esti- 
 mates of their total first cost were made; then, at an assumed rate of in- 
 terest, a table was prepared showing the total cost of each structure plus 
 interest thereon for periods of five years, up to the limit of forty years. 
 That table indicates at a glance the comparative economics of all five 
 methods at any of the five-year periods. A diagram prepared from the 
 said table, of course, would be preferable, as it would show more readily 
 the comparison at any intermediate period. 
 
 CASE IV 
 
 As stated by Lavis, "The application of economics to railroad location 
 and construction consists in the proper adjustment and balance between 
 the first cost as exemplified by the straight line of uniform rate of gradient 
 and the first cost of a line or a series of lines which deviates from it in 
 more or less degree, and the difference in cost of operation due to this 
 deviation (whether lateral or vertical), and the consequent introduction 
 of added resistance and, therefore, added cost of operation". In railroad 
 engineering there are, certainly, quite complicated preliminary economic 
 problems to solve, among which may be mentioned the following: 
 
 A. A location of the road which will ensure that the net earnings shall 
 be as large as possible; and to do this it will be necessary to run the line 
 to or through all important traffic-points which can reasonably be reached. 
 
 B. An adjustment between the character of the construction and the 
 probable gross income from traffic. If the latter be large, it will pay to 
 build a first-class road with heavy rails, light grades, easy curves, com- 
 paratively expensive station buildings, and permanent structures; but if 
 it be small, the original rails may be light, the grades comparatively 
 heavy, the curves rather sharp, the station buildings cheap, and the 
 structures temporary. 
 
 C. An adjustment between the total length of line between termini 
 and the amount of money available for construction. Under ordinary 
 conditions and within certain limits, a railway line can often be cheapened 
 by lengthening it. This, of course, is done by increasing the total amount 
 
 11 
 
of curvature, and, consequently, the cost of operation. Holbrook states 
 that for each degree of curvature there is an added train-resistance 
 equivalent to a lift of four or five hundredths of a foot, so that a complete 
 circular curvature is equivalent to a lift of about sixteen feet, or to a haul 
 of one mile on straight, level track. The energy required to overcome the 
 resistance to curvature is furnished by the engine; and the work performed 
 by the said energy is the destruction of both the equipment and the track. 
 It is difficult to determine the amount of wear of wheels due to curvature, 
 as apart from that due to straight line; but it is not so difficult to locate 
 the extra wear on the rails. From the investigations which have been 
 made on this subject, it has been found that the cost of repairs for the 
 damage done is as great as the cost of the energy expended by the engine in 
 doing it, so that the total cost of curvature, from an operating standpoint, 
 is at least twice as great as the cost of the energy necessary to overcome 
 the added resistance due thereto. 
 
 Apropos of rail-wear, it is pertinent to call attention to the ultra-con- 
 servatism of most American railroad authorities in adhering to the use of 
 rails that have their webs perpendicular to the upper faces of the ties 
 instead of perpendicular to the coned faces of the wheels. This divergence 
 from the normal, which is only one in twenty, can best be secured by using 
 beveled tie-plates. The effect of it on tangent is to reduce the rotating 
 bending-moment on the rail to zero and to bring the wear on both rails 
 and wheels to a minimum, also to make the said wear regular, uniform, 
 and parallel to the top normal plane of the rails and to the coned surfaces 
 of the wheels. In turn, this effect makes the trucks ride more easily and 
 smoothly, and thus reduces the rack on the locomotives and cars. 
 
 Again, many railroad officials object to the widening of gauge on curves, 
 in spite of the glaringly-evident fact that, unless this be done, the rigid 
 trucks will cause the wheels to grind against the inner faces of the rail- 
 heads. The necessity for this widening is so obvious that the speaker 
 cannot comprehend the obstinacy of any railroad man in adhering to the 
 maintenance of a constant gauge for both tangents and curves. Nor can 
 he appreciate the reasoning of those who refuse to incline the rail-webs 
 so as to be normal to the wheel-coning. Both of these changes in American 
 current practice are so obviously beneficial that any scientifically-thinking 
 man must concede their desirability. 
 
 Returning to the matter of curvature, there are other somewhat intan- 
 gible factors which enter into its cost-effect principally those due to the 
 limited field of view on curves. An examination into the cause of wrecks 
 and of injury and death to trackmen and others on the track discloses the 
 fact that most of these would not have happened, had there not been a 
 curve in the vicinity. The extra strain upon the track and the equipment 
 due to curves also leads to accidents which would not otherwise occur. 
 
 It is evident, therefore, that this particular economic problem involves 
 not merely first-cost of construction but also cost of operation. 
 
 D. A proper determination of the ruling grade in reference to both the 
 present and the prospective traffic. By reducing the ruling grade we make 
 it possible to handle heavier trains; and, therefore, fewer trains are neces- 
 
 12 
 
sary. This results in a saving (possibly a very large one) in the operating 
 expenses. 
 
 E. An adjustment between the total rise and fall of grades and the 
 first cost of grading. Of course, the maximum height to be surmounted 
 can very seldom be controlled to any appreciable extent, unless resort be 
 made to tunnelling in the vicinity of the summit; but the minor apices and 
 depressions can be reduced by increasing the quantities in the cuts and 
 fills. As in the last case, this economic feature is by no means one of first 
 cost only, because the total amount of rise and the cost of energy expended 
 increase and decrease together. Although it is true that some of the energy 
 stored in the train on a down grade can be utilized for climbing the next 
 rise, the amount thereof is generally small. 
 
 F. The time allowed for completing the road. This is always an 
 economic feature because of the question of interest during construction. 
 The longer the time required to finish the line and to put it in operation 
 the greater .will be the amount of the interest on the capital borrowed to 
 pay for construction; consequently it will sometimes be truly economical 
 to expend extra money on first cost in order to shorten the time for com- 
 pletion. There is another economic feature that is sometimes involved by 
 the time element, and which often becomes temporarily of paramount 
 importance, viz., the offering by communities of large bonuses in cash 
 or realty for the finishing of the road so as to bring trains to certain places 
 at or before certain times. Under such conditions, it often happens, and 
 very properly too, that every nerve is stressed to the highest tension in 
 order to accomplish the desired purpose, regardless of the amount of ex- 
 penditure of money and effort. 
 
 CASE V 
 
 In 1914 there was prepared (but never published) by Robert C. Bar- 
 nett, Esq., consulting engineer, and now associate engineer in the speaker's 
 firm, a paper entitled "A Comprehensive Policy for River Improvement". 
 This essay is a masterpiece of engineering economics; and as it relates to 
 generalities rather than to details, it is reproduced here nearly verbatim, 
 as follows, with the kind permission of its writer: 
 
 The need for a broad, comprehensive policy in dealing with our rivers 
 is again forced home on us by the recent reports of the Army Engineers, 
 the Geological Survey, and several private engineering firms. These 
 reports, emanating from different sources and inspired by different view 
 points, serve to emphasize the existing lack of correlation of purpose, of 
 coordination of plan, of cooperation in execution. 
 
 We have today various separated and unrelated organizations striving 
 to promote some form or other of river improvement. For example, 
 there are the Board of Army Engineers, the National Rivers and Harbors 
 Congress, the Geological Survey, the Mississippi River Commission, the 
 Mississippi River Levee Association, the National Drainage Congress, the 
 Interstate Levee Association, and others. There is no correlation of pur- 
 pose no coordination of effort; but each organization is seeing only its 
 own special problem and is overlooking the big fundamental problem 
 underlying the whole subject. There is so much at stake, so many in- 
 
 13 
 
terests are affected, such large investments are called for, such far reaching 
 economic benefits are possible, that it is well worth our while to pause and 
 consider what this fundamental problem is. By such consideration we 
 shall come to a better realization of what we might attain; of the inade- 
 quacy of our present system and methods; of the inefficiency of the many 
 detached and unrelated organizations now promoting river improvements; 
 and of the great need for a policy broad enough, fundamental enough, to 
 enable us to accomplish a permanent solution. 
 
 Such a policy must be based on sound economics; for the general problem 
 is essentially an economic one. What economic principle should form the 
 basis of such a policy? Let us consider a little more in detail, and perhaps 
 in an elementary way, the first principles involved. 
 
 The economic problem underlying the improvement of our streams and 
 rivers is a most fundamental one. It is but a phase of the general economic 
 problem which confronts mankind. This problem reduced to its lowest 
 terms is that of satisfying human wants. A very large part of our activi- 
 ties has this fundamental object in view. Obviously, we are directly and 
 seriously concerned with the satisfying of the maximum amount of want 
 not only the maximum amount of individual want, but of collective want; 
 for the interests of the individual are so inter-related, inter-laced, and 
 connected, so dove-tailed into each other, that the individual's maximum 
 does not obtain until the maximum for the social organism obtains. This 
 is a prerequisite for economic equilibrium. 
 
 Should our efforts fall short of producing this maximum satisfaction, 
 there remains an unattained potential increment. This unattained in- 
 crement, measured by the difference between possible attainment and 
 actual attainment, is an incentive for further effort in the future to disturb 
 conditions, to re-arrange relations, to re-adjust conflicting interests. Such 
 disturbance, such re-arrangement, such re-adjustment means an undoing 
 of the things we are doing today, a throwing away of improvements made 
 yesterday, a backing up and taking a fresh start, a wasting of time and of 
 resources. Such an unattained increment produces a corresponding in- 
 centive which is a continuous and persistent menace to our stability. It, 
 therefore, behooves us, while formulating a policy for any development, 
 to take into consideration the kind and the amount of development which 
 will ultimately produce this maximum satisfaction. Previous failure to 
 recognize this principle is today causing us to undo, or to do over, the 
 things of yesterday. Had yesterday's planning been done on a broader, 
 a more, comprehensive, a more fundamental basis, today's efforts would 
 have been in harmony therewith; and, instead of tearing out and replac- 
 ing, we should simply have to add to our former achievements, and there- 
 by get the benefit of a cumulative process of development. It is this 
 fundamental principle of producing a maximum satisfaction, or its cor- 
 relative maximum utility, that we should bear in mind when approaching 
 the problem of establishing a general policy for the improvement of our 
 rivers and streams. 
 
 What is this maximum utility which can be produced by river improve- 
 ment? If we are to formulate a policy based on maximum utility, we 
 
 14 
 
must have some conception of what that maximum utility is and how it 
 may be obtained. Heretofore, we have been prone to regard our rivers 
 as available only for one or two purposes. One such purpose, discovered 
 early in the career of mankind, is that of navigation. This continued 
 along for years, until navigation, which originally was a mere incident, 
 has come to bo regarded as the sole and primary purpose of our rivers and 
 streams. To such an extent has this view obsessed the minds of our leg- 
 islative bodies and the official heads of departments that, until recently, 
 little or no regard has been given to the other possible uses to which our 
 river systems can be put. Note, for instance, how the War Department 
 through the Army Engineers has considered navigation to be the para- 
 mount utility. These engineers have, in most cases, confined their work 
 to improvement of the channel solely for navigation purposes, ignoring 
 the adjacent flood plains and their need for protection. Note also how 
 the power development at Keokuk was penalized to the extent of $2,000,- 
 000 in order to construct a lock, a dry dock, buildings, and other improve- 
 ments, while at the same time the benefit to navigation rendered by such 
 power installation is said by river men to be worth at least $5,000,000. 
 
 THE PRIMARY AND FUNDAMENTAL PURPOSE OF OUR RIVERS AND 
 STREAMS is THAT OF DRAINING THE WATERSHEDS. This purpose obtained 
 long before the advent of man, and still continues to be the essential 
 function. Therefore, our first consideration should be to increase the 
 efficiency of these drainage channels for their respective watersheds. 
 Hence our comprehensive policy should start from this basis. To increase 
 the efficiency of a drainage channel is an engineering problem; and hence 
 it will not be considered further at this time. We might note in passing 
 that it will be found that in planning for an increased efficiency of drainage 
 channel, we may obtain other incidental but very desirable results, in- 
 cluding an augmented discharge capacity. 
 
 As the country becomes settled and land values augment because of the 
 increasing density of population and the production of wealth, the pro- 
 tection of river lands and of the property and lives of the people living 
 thereon becomes a matter of great importance. The erosion of these rich, 
 fertile, bottom lands, the destruction of crops and other property, the 
 jeopardizing of human life and often the loss thereof, all contribute to a 
 far-reaching loss which becomes a burden to the rest of the country as 
 well as to the afflicted districts; hence our comprehensive policy should 
 recognize this very important element of the general problem. How to 
 secure flood protection is purely an engineering question, and will be passed 
 over for the present. 
 
 The need for transportation becomes more urgent as the country settles 
 up and as population concentrates at certain points. Water transporta- 
 tion is more economic for certain classes of freight than rail transportation, 
 hence it is to the general interest of the country to facilitate the former, 
 consequently the navigability of our rivers should receive consideration 
 in our comprehensive policy. How to improve navigation is another 
 engineering problem; and, as such, it will be passed over for the present. 
 
 As the river towns expand into large cities, the need for a municipal 
 water supply becomes of corresponding importance, and, hence, should 
 
 15 
 
receive attention in the formulation of our comprehensive policy. The 
 securing of a water supply is likewise an engineering problem. 
 
 In certain arid and semi-arid sections of the country the needs of irri- 
 gation are paramount; and, as a matter of fact, in other sections favored 
 ordinarily with abundant rainfall there may come a drought at the critical 
 growing time, so that irrigation is much needed even there. Hence our 
 comprehensive policy must recognize the demand for irrigation. How to 
 provide and divert water for irrigation is also an engineering problem. 
 
 The development of the country's resources is making a larger and 
 larger demand for cheap power. Statistics show that the utilization of 
 power has increased from 2,346,142 H. P. in 1870 to 14,641,544 H. P. in 
 1905. This shows an increase in the per capita consumption of from 
 0.060 H. P. to 0.177 H. P. We must be prepared for an increasing number 
 of power installations to meet the growing demands of an increasing pop- 
 ulation and an increasing per capita consumption. Many of our rivers 
 and streams have power possibilities; and the utilization of these is of the 
 greatest economic concern to the entire country, hence our comprehensive 
 policy should provide encouragement for water power development. The 
 actual planning for power and the development thereof from our rivers 
 and streams constitute an engineering problem; and, therefore, will be 
 passed over for future consideration. 
 
 From the foregoing, we see that a comprehensive policy for river devel- 
 opment seeking to obtain the maximum utility should provide for the 
 following: 
 
 (a). An efficient drainage channel and an increased discharge capacity. 
 
 (b). Protection from floods, together with reclamation of low lands, 
 drainage, and prevention of erosion. 
 
 (c). Improved navigation facilities. 
 
 (d). Municipal water supply and incidental storage of flood waters. 
 
 (e). Irrigation, with its incident diversion-canals and its storage of 
 flood waters. 
 
 (f). Water power development and its storage of flood waters. 
 
 While it is recognized that each stream presents its own special problem 
 and requires a specific solution to meet actual conditions, yet it is readily 
 seen that should we fail to plan for the ultimate development of all its 
 utilities, we fall short by that much of reaching a maximum. Likewise, 
 if we develop one utility at the expense of another, we fail to reach the 
 maximum. What is needed is a plan or program that will permit of a 
 balanced development. A comprehensive policy embracing these features 
 will make it possible in many cases to obtain a number of them with one 
 investment. 
 
 For example, if it be desired to provide a more efficient drainage channel 
 in order to discharge floods for some watershed, it may be found possible 
 to provide at the same time levees that will protect the lowlands from 
 overflow and also give an increased efficiency to the channel. The matter 
 of bank protection and the prevention of erosion could be taken care of in 
 the same improvement. By the careful selection of a suitable channel- 
 cross-section and the maintenance thereof, navigation facilities could be 
 
 16 
 
improved during low water, and yet at high water the discharge capacity 
 of the channel would not be interfered with. If at the same time our plan 
 of development include diversion canals and storage reservoirs, we can 
 relieve somewhat the peak of the flood-flow while storing up water for 
 irrigation, municipal supply, or power purposes. Such an adjustment of 
 related interests and conditions could be obtained that a maximum 
 utility would result. 
 
 In contrast with this, consider some of the actual conditions confront- 
 ing us today. We find cases where levees have been built for flood pro- 
 tection to the detriment of the channel. That is the levees on opposite 
 sides of the river approach and recede from each other over a wide range, 
 thereby forming an irregularly varying channel-cross-section of changing 
 area and differing hydraulic radius with a consequent variation in velocity, 
 so that, during floods, silt is being picked up at one stretch of the river and 
 deposited in another; and we get the effect in places of raising the river 
 bed above the elevation of the adjoining bottom lands. We find cases 
 where dams and locks have been built to improve navigation but no 
 attempt has been made to utilize the resulting head for power development. 
 
 Again, consider the case of a constructively navigable stream that will 
 hardly float a motor boat a large part of the year and yet is rich in power 
 possibilities. Under our comprehensive policy, power development 
 would be encouraged. The building of one or more dams would provide 
 slack-water navigation for certain reaches, while at the same time storing 
 water for power purposes. The storage of flood waters and their subse- 
 quent gradual release through the power plant would equalize the flow 
 below the dam so that navigation would be greatly benefited thereby. The 
 development of cheap power would bring in its wake more industries, more 
 population, more need for water transportation, and a great building up of 
 the community, all of which leads towards the production of maximum 
 utility. 
 
 Other examples could readily be cited; but it is believed that enough 
 has been said to show the possibilities to be obtained by the formulation 
 of a comprehensive policy and to indicate the economic basis upon which 
 such a policy should rest. 
 
 However, the excessive floods of last spring have forced home the urgent 
 need for protection; and in our anxiety to provide such protection we are 
 apt to overlook the fact that the protection problem is but a phase of a 
 larger and more fundamental problem. Unless this fundamental problem 
 of obtaining the maximum utility is kept before the minds of our legisla- 
 tors and departmental heads, we are apt to get only a partial solution of 
 it because of the desire to provide immediate protection and relief. The 
 investment that we may now make for partial relief will very likely have 
 to be discarded later on, unless it is made with the view of fitting into the 
 final development. It would be better and, in the long run, more econom- 
 ical to conform to a comprehensive plan looking toward ultimate develop- 
 ment, even though it take years to carry out such a program. We should 
 have a very material advantage in pursuing a definite general policy, such 
 that the work done in the early period of development would not have to 
 be undone at some later stage and a costly investment discarded. 
 
 17 
 
Under a general comprehensive policy, our work could be planned in 
 such a way that we should continually be building up and strengthening 
 all investments and improvements. The desirability and efficiency of 
 such a policy must be recognized by all students of the situation. 
 
 How to impress the great need of such a policy on the minds of our 
 public men, legislators, and officials of various departments, on various 
 state and local organizations now aiming at some one detail in improve- 
 ment, is the serious question. 
 
 It has been seen that each feature to be covered by the general compre- 
 hensive policy required for its attainment involves the solution of an 
 engineering problem. This being the case, the formulation of such a 
 general comprehensive policy could best be done by engineers who are 
 experts in the several lines involved. It is here that our National Engi- 
 neering Societies could perform a service for the country in general and 
 for the profession at large by appointing a joint committee to outline such 
 a policy and a tentative program for securing its adoption and execution. 
 After the joint committee had recommended for adoption a comprehensive 
 policy embracing the idea of a balanced development of our river systems 
 so that a maximum utility would result, local engineering societies and 
 individual engineers could well assist the National Societies by taking up 
 the work of presenting such a policy to their respective congressmen. 
 
 As the primary purpose of this communication is to emphasize the need 
 for a comprehensive policy and to impress on the minds of all engineers 
 the importance of the engineering profession's taking a hand in formulating 
 such a policy and in outlining a skeleton program, the writer will only 
 attempt at this time to mention briefly some salient features thereof, 
 leaving for a future article the presentation of a more developed program. 
 It is believed that the salient features of such a preliminary program 
 should be the following: 
 
 An act of Congress adopting the comprehensive policy, to be recom- 
 mended by the Joint Committee of the National Engineering Societies, 
 and providing for a Coordinating Board of Engineers, the manner of select- 
 ing them, and their compensation. 
 
 The cooperation of the States with the National Government. 
 
 A division of affected territory based on watersheds of convenient size. 
 
 The appointment by each interested State of a State Board of Engineers 
 for this particular work, and to provide for their compensation by the 
 State. 
 
 Each State Board to work out tentative plans for developing the 
 utilities .of its own rivers and streams. 
 
 Where a watershed embraces more than one state, the several State 
 Boards interested to select from their own membership a member of the 
 Watershed Board, so that each State would be represented on the said 
 Watershed Board. 
 
 The Watershed Board to harmonize the plans of the several State 
 Boards under it. 
 
 The various Watershed Boards to meet with the Board of Army Engi- 
 neers and Federal authorities from time to time and cooperate in perfect- 
 ing plans. 
 
 18 
 
The various Watershed Boards, the Board of Army Engineers, and the 
 Federal authorities to select an even number of members to form the 
 Coordinating Board of Engineers, as provided by act of Congress. These 
 members in turn to select from the country at large an additional odd 
 number of engineers to complete this Board. 
 
 The purpose of the Coordinating Board should be to perfect the details 
 of the program for carrying out the purposes of the general comprehensive 
 policy, to harmonize general plans for execution, and to apportion the 
 expense of any improvement to those interests receiving the benefit of 
 such improvement, whether these be individuals, cities, counties, states, 
 or the general government. 
 
 While all this seems like a very large undertaking, yet the benefits to 
 be derived by it are of the same magnitude; and they will eventually 
 justify such a program and the investments made in accordance therewith. 
 
 The general features of economics in respect to the inception and finan- 
 cing of engineering projects have now been described at some length for 
 bridges, railroads, and river improvement; and this treatment of the sub- 
 ject should suffice for an example of how to handle the preliminary eco- 
 nomic questions in all other lines of technical activity. 
 
 We can now pass to the second division of these lectures, viz., the 
 economics of design and construction; and in so doing it is practicable 
 to enter much more into detail than we have previously; but before dealing 
 with certain of the numerous specialties into which engineering is divided, 
 we shall touch lightly upon a few general matters pertaining to the eco- 
 nomics thereof. 
 
 Anticipating The Future 
 
 In all engineering work of both designing and construction, true economy 
 necessitates a thorough consideration of future requirements and possible 
 eventualities, also a provision for meeting the same. For instance, in 
 designing a structure one should consider possible future additions of 
 loading and how to accommodate them; and in construction one should 
 anticipate delays, floods, storms, and other possible difficulties, and should 
 prepare his programme so as to meet them effectively and without any 
 unnecessary expenditure of time, labor, or money. Foresight of this kind 
 is an important element of success in the career of every engineer. 
 
 Systemi? ation 
 
 Quoting from the speaker's treatise on "Bridge Engineering", "The 
 systemization of all that one does in connection with his professional work 
 is one of the most important steps that can be taken towards the attain- 
 ment of success". Moreover, it is one of the fundamental elements of 
 economics in all lines of work. 
 
 Time Versus Material 
 
 Some designers in their endeavor to save a small amount of material 
 expend a large amount of time, not only of their own but also of other 
 people's, which time when properly evaluated is often greatly in excess 
 of the cost of the material saved. Such economy as this is false; and its 
 practice is unscientific. 
 
 19 
 
Labor Versus Material 
 
 Similarly some designers in an endeavor to cut down quantities in their 
 structures increase the labor thereon to such an extent that the material 
 saved is worth only a small portion of the value of the extra labor expended. 
 For instance, if one were to make a small pier hollow, the concrete thus 
 saved would not be worth anything like as much as the cost of the forms 
 required to construct the hollow space. 
 
 Recording Diagrams 
 
 The study of economics is greatly facilitated by the use of diagrams 
 that record quantities of materials, costs of construction, times of opera- 
 tion, etc., for varying conditions. In general, it may be stated that 
 American engineers do not use graphics for studying economics to the 
 extent which is advisable; and that in this they might learn something 
 from their European brethren. 
 
 Economics of Mental Effort 
 
 Almost nothing concerning this important subject is taught in our 
 technical schools; and but little is known about it by practicing engineers. 
 To be a truly successful engineer, one has need to study deeply the matter 
 of how best and most economically to utilize his mental forces; how to 
 accomplish the greatest amount of work with the smallest expenditure of 
 effort; how many hours of work per day for long-continued labor will 
 effect the largest accomplishment; to what extent men in various lines of 
 activity should take vacations, and how these should be spent; what are 
 the effects upon one's working capacity from the use of liquor and tobacco 
 in both small and large quantities; etc. All these are ecomonic questions 
 of great importance; and they need to be given proper attention by every 
 engineer who aspires to efficiency in both himself and his employees. 
 
 Again, the development of the faculty of concentration is an economic 
 consideration of much importance. 
 
 Economics In Office Practice 
 
 There are many conditions in ordinary office practice that are suscepti- 
 ble of considerable improvement from the economic point of view for 
 instance, unnecessary conversation, useless duplication of labor, and lack 
 of proper checking; but this matter is too complicated and lengthy to 
 warrant more than mere mention in a lecture of this kind. The subject 
 will be found very thoroughly treated in Chapter LVIII of the before- 
 mentioned treatise on "Bridge Engineering". 
 
 Economics Of Manufacture 
 
 This is a subject of such complication and extent that it can merely be 
 mentioned here; for upon it a large treatise might readily be written. It 
 will suffice to say that the prime requisites are the prompt furnishing at 
 all times of materials and tools; the keeping on hand of spare parts of 
 machinery which are liable to breakage or wear; the proper upkeep of all 
 machinery and apparatus; the systematic arrangement for carrying work 
 through the shops, preferably always in one direction; the avoidance of 
 duplication of labor; the prevention of errors, and the speedy correction 
 
 20 
 
of those which unavoidably occur; the development of individual efficiency 
 in all employees; the maintenance of a contented spirit among the work- 
 men; and the constant and intelligent supervision of all work. 
 
 Economics Of Construction 
 
 This subject like the one last discussed is of great complication, and in 
 general principles the two have much in common. For instance, there 
 should be prepared for each piece of construction an elaborate programme, 
 indicating the various steps to be taken and how the work should be 
 carried out. Diagrams in this connection are most useful. Again, there 
 should be prepared a time-schedule for the completion of the various 
 divisions of the work; and this should invariably be lived up to when it is 
 
 There should be a pre-arranged schedule for the furnishing of all mater- 
 ials and supplies; adequate means for the transportation thereof should be 
 provided; the workmen should be well housed and fed; and should be made 
 comfortable and contented; disagreements between heads of departments 
 should be prevented; all possible difficulties should be anticipated, and 
 means should be at hand to meet and overcome them; ample funds should 
 be provided for paying promptly all bills for labor and materials; liquor 
 should be kept away from the workmen; and strike organizers and other 
 troublesome people should be run off the job. 
 
 All these matters are directly concerned with the economics of construc- 
 tion. 
 
 Labor 
 
 The scientific handling of labor is an economic problem of the utmost 
 importance, and a treatise could well be written on the subject. The 
 principal desideratum is to keep the workmen well, happy, and contented; 
 and the best ways to do this are to treat them kindly, make them com- 
 fortable, feed and house them well, amuse them in their spare time, don't 
 work them too long hours, pay them by piece-work when practicable, 
 listen patiently to their complaints, right their wrongs, see that they are 
 well taken care of when they are ill or injured, and evolve, if possible, 
 some feasible method of sharing profits with them. On the other hand, 
 though, drive them hard and continuously during working hours, insist 
 upon their putting in overtime when the conditions truly require it, dis- 
 charge instantly all insubordinate or otherwise troublesome men, dis- 
 pense quietly with the services of all shirkers, and insist that everybody 
 put forth his best and most intelligent effort to effect the maximum of 
 accomplishment in the minimum of time. 
 
 Waste 
 
 In all lines of activity the avoidance of waste or extravagance and the 
 utilization of by-products are today burning questions; and upon their 
 proper solution by American scientists will depend greatly the success 
 of our country in its commercial struggle with the nations of Europe and 
 Asia. This statement is just as true concerning engineering as it is of any 
 other activity; and it is encouraging to see that a number of our leading 
 technical institutions are inaugurating research departments for the 
 
 21 
 
furtherance of this object. Prominent among them in this work, the 
 speaker is pleased to say, is the University of Kansas. 
 
 Efficiency Experts 
 
 A very new type of specialist in engineering is the efficiency expert 
 the man who takes hold of moribund factories and other decaying enter- 
 prises, studies them thoroughly so as to determine the raison d'etre for 
 their decline, evolves the proper remedies for their troubles, puts them 
 again upon their feet, and starts them upon the high road to success. It 
 is mainly in little matters, apparently of small importance, that such 
 concerns fail; and it requires a high development of unusual talent in an 
 engineer to become a truly successful efficiency expert. Such work as 
 his no one can deny being "engineering economics" in the truest sense 
 of the term; and the specialty is surely destined to become more and more 
 popular and important as the years pass by. 
 
 LECTURE II 
 
 Having completed the discussion of the principal topics of a general 
 nature pertaining to the economics of designing and construction, it is 
 now in order, as previously explained, to take up the various engineering 
 specialties, concerning the economics of which the speaker has been able 
 to collect sufficient data for his purpose; and these will be treated in alpha- 
 betical order. Fortunately (or otherwise) the first of the group is the line 
 of engineering activity in which the speaker has specialized during more 
 than three decades, and in which his numerous writings, extended over a 
 long series of years, deal at great length with the important subject of 
 economy. On that account, the volume of data at hand is unusually 
 large; and this is the explanation of the fact that the treatment of this 
 subject is much fuller in detail than that of any of the others. It is hoped 
 that the speaker will be pardoned for making numerous and somewhat 
 lengthy quotations from his latest treatise, as it was issued only last 
 summer, and as he cannot well improve upon what he has said therein 
 upon the subject of "True Economy in Design". 
 
 The great majority of bridge designers believe that the most economic 
 structure is the one for which the first cost is a minimum; and from the 
 contractor's prejudiced point of view this is correct, because his interest 
 generally lies in securing the contract for the work regardless of all other 
 considerations than his own profit; but from the purchaser's point of view 
 that structure is the most economic which will do the work required of it 
 for as long a time as necessary with the least possible expenditure for 
 operation, maintenance, and repairs, all these desiderata being obtained 
 with the smallest practicable initial cost of construction. 
 
 Treatise after treatise has been written upon the subject of economy in 
 superstructure design, but unfortunately the result is simply a waste of 
 good mental energy; for the writers thereof invariably attack the problem 
 by means of complicated mathematical investigations, not recognizing 
 
 22 
 
the fact that the questions they endeavor to solve are altogether too in- 
 tricate to be undertaken by mathematics. The object of each investiga- 
 tion appears to have been to establish an equation for the economic depth 
 of truss, or that depth which corresponds to the minimum amount of 
 metal required for the said truss; and, to start the investigation, it seems 
 to have been customary to make certain assumptions which are not even 
 approximately correct. For instance, the principal assumption of several 
 treatises in French and English is that the sectional area and the weight 
 of each member of a truss are directly proportional to its greatest stress; 
 or, in other words, that in proportioning all members of trusses a constant 
 intensity of working stress is to be used, while in reality for modern steel 
 bridges the intensities often vary considerably in the same specifications. 
 Again, no distinction is made between tension and compression members, 
 and no account is taken of the greatly varying amounts of their percent- 
 ages of weights of details. 
 
 There is, however, one mathematical investigation concerning eco- 
 nomic truss depths which is approximately correct, and which is based 
 on assumptions that arc very nearly true; but it holds good only for 
 trusses with parallel chords, for which structures it shows that the greatest 
 ecomony of material will prevail when the weight of the chords is equal to 
 the weight of the web. 
 
 It has been found by experience that, for trusses with polygonal top 
 chords, the economic depths, as far as weight of metal is concerned, are 
 generally much greater than certain important conditions will permit to 
 be used. For instance, especially in single-track, pin-connected bridges, 
 after a certain truss depth is exceeded, the overturning effect of the wind- 
 pressure is so great as to reduce the dead-load tension on the windward 
 bottom chord to such an extent that the compression from the wind load 
 carried by the lower lateral system causes reversion of stress, and such 
 reversion eye-bars are not adapted to withstand. A very deep truss re- 
 quires an expensive traveller, and decreasing the theoretically economic 
 depth increases the weight but slightly; hence it is really economical to 
 reduce the depth of both truss and traveller. Again, the total cost of a 
 structure does not vary directly as the total weight of metal, for the reason 
 that an increase in the sectional area of a piece adds nothing to the cost 
 of its manufacture, and but little to the cost of erection; consequently 
 it is only for raw material and freight that the expense is really augmented. 
 Hence it is generally best to use truss depths considerably less than those 
 which would require the minimum amount of metal. For parallel chords, 
 the theoretically economic truss depths vary from one-fifth of the span 
 for spans of 100 feet to about one-sixth of the span for spans of 200 feet; 
 but for modern single-track-railway through-bridges the least allowable 
 truss depth is about 30 feet, unless suspended floor-beams be used, a detail 
 which very properly has gone out of fashion. 
 
 In designing plate-girders, if one will adopt such a depth as will make 
 the total weight of the web with its splice-plates and stiffening angles 
 about equal to the weight of the flanges, he will obtain an economically 
 designed girder, and a deep and stiff one. For long spans, however, this 
 arrangement would make the girders so deep as to become clumsy and 
 
 23 
 
expensive to handle; consequently, when a span exceeds about forty feet, 
 the amount of metal in the flanges should be a little greater than that in 
 the web; and the more the span exceeds forty feet the greater should be 
 the relative amount of metal in the flanges. 
 
 A rather lengthy mathematical investigation for plate-girders, based 
 upon fairly accurate assumptions, proves that the theoretical maximum 
 of economy exists when the gross areas of flanges and of web at mid-span 
 are equal a condition readily remembered. Although this is the theoret- 
 ically correct criterion for economy, if it be applied to any particular case, 
 it will generally be found that the resulting web depth is so excessive as 
 to cause one or more of the following modifications in construction, as 
 compared with the depth which would make the total weight of the flanges 
 equal to the total weight of the web with all its details: 
 
 A. An additional splice or two in the web, or else a slightly increased 
 pound price for the large plates. 
 
 B. Larger outstanding legs for all stiffening angles. 
 
 C. Reduction in the number of cover plates. 
 
 D. Narrowing of flange angles and necessitating thereby either an ad- 
 ditional bracing frame or an increase in sectional area of the compression 
 flange, in order to compensate for the greater ratio of unsupported length 
 to width. 
 
 E. Possible thickening of web because of its greater depth. 
 
 F. Possible encroachment on under-clearance in deck spans, or raising 
 of grade to avoid the same. 
 
 G. Possible difficulty in fabrication or shipment in case of long or 
 heavy girders because of excessive depth. 
 
 Any of these changes would be likely so to upset the economics of the 
 case as to cause a material decrease in the theoretically best depth, hence 
 it is generally advisable to adhere to the rule previously given; but there 
 are occasionally cases where a saving of metal may be effected by making 
 the web depth somewhat smaller, when by so doing a web-splice may be 
 avoided or lighter stiffening angles may be adopted. It should be borne 
 in mind that there is quite a range in web-depths over which the theoretic 
 minimum weight is about constant, unless the thickness of the shallower 
 web must be increased on account of shear; hence one may often vary 
 the dimensions of a plate-girder materially without affecting greatly 
 the matter of economics. In Chapter XXI of "Bridge Engineering" 
 there is given a diagram of economic depths of plate-girders with riveted 
 end connections. 
 
 Concerning economic panel lengths, it is safe to make the following 
 statement: Within the limit set by good judgment and one's inherent 
 sense of fitness, the longer the panel the greater the economy of material 
 in the superstructure. Of course, when one goes such an extent as to 
 use a thirty-foot panel in an ordinary single-track-railway bridge he 
 exceeds the limits referred to, because the lateral diagonals become too 
 long, and their inclination to the chords becomes too flat for rigidity. 
 Again, an extremely long panel might sometimes cause the truss diagonals 
 to have an unsightly appearance because of their small inclination to 
 the horizontal, 
 
 24 
 
There is another mathematical investigation which is of practical 
 value. It relates to the economic lengths of spans, and was first demon- 
 strated in print by the speaker some twenty-six years ago in "Indian En- 
 gineering, " although the principle was announced three years before then 
 in the first edition of his "General Specifications for Highway Bridges 
 of Iron and Steel". Strange to say, many engineers failed to see that 
 there is any difference between this principle and an old practice of over 
 fifty years' standing. The principle is that "for any crossing the great- 
 est economy will be attained when the cost per lineal foot of the sub- 
 structure is equal to the cost per lineal foot of the trusses and lateral 
 systems". The old practice was to make for economy the cost of a pier 
 equal to the cost of the span that it supports, or, more properly, equal 
 to one-half of the cost of the two spans that it helps to support. Is not 
 the difference between these two methods perfectly plain? In one the 
 cost of the pier is made equal to the cost of the trusses and laterals, and 
 in the other it is made equal to the cost of the trusses, laterals, and floor 
 system. When one considers that the cost of the floor system is some- 
 times almost as great as one-half of the total cost of the superstructure, 
 he will recognize how faulty the old method was. 
 
 As just indicated, the demonstration referred to proves that in any 
 layout of spans, with the conditions assumed, the greatest economy will 
 be attained when the cost of the substructure per lineal foot of bridge is 
 equal to the cost per lineal foot of the trusses and lateral systems. Of 
 course, no such condition as a bridge of indefinite extent ever exists, nor 
 is the bed-rock often level over the whole crossing; nevertheless the prin- 
 ciple can be applied to each pier and the two spans that it helps to support 
 by making the cost of the pier equal to one-half of the total cost of the 
 trusses and laterals of the said two spans. 
 
 The principle will apply also to trestles and elevated roads; for in the 
 latter, when there is no longitudinal bracing, if we make the cost of the 
 stringers or longitudinal girders of one span equal to the cost of the bent 
 at one end of same, including its pedestals, we shall obtain the most 
 economic layout. In an ordinary railroad trestle consisting of alternating 
 spans and towers, it will be necessary for greatest economy to have the 
 cost of all the girders in two spans (one span being over the tower) plus 
 the cost of the longitudinal bracing of one tower equal to the cost of the 
 two bents of said tower,.. including their pedestals. 
 
 The economics of reinforced concrete bridges have not received much 
 attention from technical writers; and they are rather difficult to deter- 
 mine, as the quantities involved are influenced quite largely by the in- 
 dividual taste of the designer. The problem is also complicated by the 
 facts that the unit costs of the various portions of a structure may be 
 more or less different, and that the unit costs of different types of con- 
 struction may be decidedly unlike. In general, it may be said that the 
 unit costs are lower for those structures which have the simplest form- 
 work; and a reduction will also be effected by decreasing the area of form- 
 surface per cubic yard of concrete. For instance, in the case of a wall 
 or slab the form-cost per cubic yard will vary practically inversely as the 
 thickness of the said wall or slab. Evidently, therefore, it is desirable to 
 
 25 
 
concentrate the concrete into a few large members, rather than to employ 
 a great number of small ones. 
 
 It should be noted that reinforcing bars less than % in. in diameter 
 command higher pound prices than do the larger bars. The extras for 
 these small bars may be found in Engineering News the first of each month. 
 
 Taking up, first, girder bridges carried on columns, the following points 
 must be considered: 
 
 First. The panel length, when cross-girders are employed. 
 
 Second. The number and spacing of the longitudinal girders. 
 
 Third. The number of columns per bent. 
 
 Fourth. The span length. 
 
 Fifth. The use of reinforced concrete piles to carry the footings. 
 
 The panel length adopted is usually not of great importance from the 
 standpoint of economy. Lengths of from eight to ten feet are generally 
 employed; but a considerable variation from these values will cause little 
 change in the combined cost of the slabs and cross-girders. A reduction 
 in concrete quantities can frequently be effected by using long panels, 
 and by carrying the slabs on short stringers supported by the floor-beams; 
 but the extra form-work required will generally overbalance this saving 
 in volume. 
 
 The number and spacing of the longitudinal girders will depend upon 
 the width and the height of the structure, the span-length, and the load 
 to be carried. For a high structure in which the economic span-length 
 is fairly long, it will nearly always be found best to employ two lines of 
 girders, the spacing thereof being equal to about five-eights of the total 
 width of the structure; but for bridges much over sixty (60) feet wide, the 
 use of three or even four lines may be preferable. The slab in such struc- 
 tures is carried on cross-girders and cantilever-beams. For a low bridge 
 in which the economic span-length is short, it will generally be the cheapest 
 to omit the cross-girders, except at the bents, and to employ several lines 
 of longitudinal girders. The wider the structure, the more likely will 
 this arrangement prove to be economical; and very heavy loads also favor 
 its adoption. For a structure in which the span-length is from one-half 
 to two-thirds of the width, it will usually make little difference which of 
 the two types is adopted, unless the height is rather large; and even in 
 extreme cases the variation between the two is not likely to exceed ten 
 per cent. Ordinarily, it will be found more desirable to use two lines 
 of girders, with cross-girders and cantilevers about eight or ten feet 
 centres. 
 
 The proper number of columns per bent depends on the number of 
 longitudinal girders. When there are only two lines, two columns will, 
 of course, be employed. When there arc several lines of girders, there 
 should generally be one column per girder in low structures, and two 
 columns per bent in higher ones. In this latter case a heavy cross-girder 
 will be required at each bent to carry the longitudinal girders. 
 
 The economic span-length is affected by the height and the load, being 
 larger for greater heights and smaller for heavier loads. An approximate 
 
 26 
 
value thereof is given by the formula 
 
 in which I = economic span length, centre to centre of supports, 
 
 w = load per lineal foot of girder (excluding its own weight), 
 and h = fixed height of structure. 
 
 The quantity h represents in any given case the height which is fixed, such 
 as the height from grade to top of footing, height from grade to bottom of 
 footing, height from underside of girder to top of footing, or height from 
 underside of girder to bottom of footing, as the case may be. There is 
 always a considerable range of lengths for which the quantities remain 
 nearly constant. The formula gives values a trifle greater than those for 
 which the quantities are a minimum, since the use of heavier sections will 
 reduce slightly the unit costs of the concrete. 
 
 Reinforced-concrete piles should be used under footings when a suit- 
 able foundation is to be found only at a considerable depth, or when a very 
 large footing area would be required in order to reduce the pressure to 
 a proper amount. A comparison must be made for each case as it arises, 
 allowing properly for the cost of the column shaft, the footing, the piles, 
 and the excavation. This latter item must not be overlooked. 
 
 In arches the problem is much more complicated than in girder spans. 
 The factors that affect the economic lengths are the cost of the arch ribs 
 and that of the piers and abutments, the dividing lines between them 
 being the verticals through the springing points. For any fixed span- 
 length the greater the rise, up to a limit of nearly one-half of the opening, 
 the smaller will be the costs of both the arch and the piers or abutments 
 which sustain it; but in most cases the distance from grade to ground is 
 too small to permit the adoption of such a large rise; hence the problem 
 generally resolves itself into a determination of the question, "How long 
 can the span be made economically for a certain limit of rise?" This will 
 be influenced by several important considerations, among which may be 
 mentioned the following: 
 
 A. The live load used. 
 
 B. The amount of earth fill, if any, over the arches. 
 
 C. The depth of the foundations for the piers and abutments below 
 the springing points. 
 
 D. The cost per cubic yard for putting the bases of piers and abut- 
 ments down to a satisfactory foundation. 
 
 E. The necessity for a heavy or substantial appearance of the piers 
 and abutments. 
 
 F. The height to which the large pier shafts must be carried. 
 
 G. The condition of the arch barrel whether solid or ribbed. 
 
 H. The necessity, or otherwise, of adopting certain span-lengths to 
 meet existing conditions. 
 
 Here are too many variables for a theoretically correct economic in- 
 vestigation, hence the surest and most satisfactory way to proceed is to 
 make by judgment the best possible layout consistent with the condi- 
 tions, then two others, one involving a span-length a certain number of 
 
 27 
 
feet greater and the other a span-length the same number of feet less, 
 and figure the costs of arches and piers (or abutments) for all three cases. 
 Instead, though, of increasing and decreasing the span by a certain num- 
 ber of feet, it may be necessary to reduce and augment the number of 
 spans by unity. After the costs of the arches and piers or abutments 
 are found and properly combined, the cost of these two portions of the 
 construction per lineal foot of span for each of the three layouts can be 
 computed and compared. The one which gives a minimum will indicate 
 approximately the best span-length to adopt. 
 
 In some cases it will prove to be economic to make the middle span 
 of the bridge a certain length and reduce gradually the lengths of the 
 spans at each side. If the configuration of the crossing will permit of 
 a symmetrical layout on this basis, the effect will prove to be pleasing 
 to the eye and generally economic of first cost, especially if a constant 
 ratio of rise to span be maintained; because, as far as cost of substruc- 
 ture is concerned, the overturning moments from live load on a single 
 span only and from inequality of dead load thrusts are kept low, owing 
 to the fact that the lighter thrusts in the smaller span act with a greater 
 lever arm than do the heavier thrusts of the longer span, on account of 
 higher location of the points of springing. In adopting this expedient, 
 though, care has to be exercised to prevent the principles of aesthetics from 
 being violated. 
 
 There are many minor economic questions that arise in the designing 
 and construction of bridges, among which may be mentioned the economic 
 greatest lengths of different types of spans; the character of approaches 
 to bridges; column spacing in bents supporting cross-girders with canti- 
 lever brackets; the economic functions of swing spans, cantilever bridges, 
 arches, and steel trestles; the height of concrete retaining walls at which 
 it is economic to begin to use reinforcing; the relative economics in em- 
 ploying medium steel, soft steel, standard steel, and alloy steel for bridge 
 superstructures; the effect of erection on the economic layout of spans; the 
 comparative economics of rim-bearing and centre-bearing swing-spans; 
 economy in choice of metal sections; and economy in shopwork. These 
 various economic questions will now be taken up in the order enumerated. 
 
 Comparing rolled I-beam and plate-girder deck spans for modern 
 heavy live loads, the weights of metal are about equal for spans of fifteen 
 feet; but the former are cheaper per pound than the latter by about 
 four-tenths (0.4) of a cent, consequently the costs per lineal foot erected 
 are equal for a span of about twenty feet. 
 
 Comparing deck plate-girders and through, riveted truss-spans, for 
 which there is usually a difference of about one-half cent per pound erected 
 in favor of the former the weights of metal per lineal foot are the same 
 for spans of one hundred and fifteen (115) feet, which is about the ex- 
 treme limit of length for plate-girder spans shipped in one piece; hence 
 it may be concluded that for all practicable lengths, deck plate-girder spans 
 are more economic than through, riveted truss-spans. Besides, the use 
 of such deck spans effects a great economy in the substructure by reduc- 
 ing the length of each pier from six to ten feet, the longer the span, of 
 
 28 
 
course, the less the reduction. It generally reduces also the heights of 
 the piers. 
 
 Comparing half-through, plate-girder spans and through, riveted truss- 
 spans, for which there is a difference of about two-tenths (0.2) of a cent 
 per pound erected in favor of the former, the weights of metal per lineal 
 foot are the same for spans of seventy (70) feet, but the costs per foot 
 are about equal for spans of seventy-five (75) feet. However, as plate- 
 girder spans are in many respects more satisfactory than short, through, 
 riveted spans, the dividing point is generally placed at about one hundred 
 (100) feet. 
 
 Comparing Pratt and Petit truss-spans, for which there is no difference 
 worth mentioning in the pound prices of the metal, the weights per foot 
 (and therefore the costs) are alike for single-track spans of three hundred 
 (300) feet, and for double-track spans of three hundred and fifty (350) 
 feet; but both constructive and aesthetic reasons necessitate limiting the 
 lengths of Pratt trusses to about three hundred and twenty-five (325) feet. 
 
 The economics of approaches to bridges will involve the question of 
 whether it is best and cheapest to build earth embankments, timber 
 trestles, or steel viaducts, and at what heights it would pay to change 
 from one kind to the other. It can be readily solved by employing the 
 numerous diagrams of Chapters LIII to LVI, inclusive, of "Bridge En- 
 gineering". 
 
 The economics of column spacing for bents when cantilever brackets 
 are employed is an interesting little problem, but the final determination 
 must be in accordance with good judgment as well as economy; for if 
 the spacing be too small, rigidity is likely to be sacrificed. Upon certain 
 assumptions of approximate correctness, the mathematical solution of 
 this problem is a possibility; but the equations involved would be so 
 complicated that it is much better for any particular case to assume two 
 or three spacings, compute the total weight of metal in the bent for each, 
 and find the one which will give approximately the least weight of metal. 
 If the columns are placed at the quarter points of the beam, the dead load 
 bending moment at the middle will be approximately zero; and if the 
 effect of stress reversion is ignored, the direct and reverse bending moments 
 for the central portion of the beam will be equal, and this arrangement 
 would be about the most economical possible. But if the reversion is 
 considered, the sectional area of the middle portion of the beam must be 
 greater than that of the outside portions, hence for economy its length 
 should be somewhat less than one-half of the total, and the columns 
 would then be spaced somewhat closer than when they are located at the 
 quarter points. The fact that the brackets are usually lighter near the 
 outer ends than at the inner ones would, for economy, tend to draw the 
 columns together; but on the other hand this would increase the weight 
 of the splices and connecting details. The proper column spacing to adopt 
 will depend upon the length of the columns; for it is easily conceivable 
 that the structure could be so high and so narrow that the quarter-point 
 spacing would be too close for proper resistance to wind pressure. Again, 
 in such a case the wind load might be so great as to necessitate an increase 
 in column section above that required to care for the live and dead load 
 
 29 
 
stresses only; and thus the effect of wind pressure would enter the eco- 
 nomic study. It will be found in most cases that it is inadvisable to space 
 the columns much less than one-half of the total length of the beam. 
 
 The economic functions of swing spans are somewhat difficult to for- 
 mulate. The minimum perpendicular distance between central planes of 
 trusses for first-class construction should be the same as for simple-truss 
 spans, viz., one-twentieth of the span length. It is evident, of course, 
 that the narrower the bridge the less it will weigh and cost. The truss 
 depths at ends of through swing bridges are generally determined by the 
 clearance requirements; but in long spans it is sometimes advisable, for 
 the sake of vertical stiffness and to avoid the raising of span-end from a 
 load on the other arm, to make the said depths still greater. As a rule, 
 this increase is not of an uneconomic nature. For long spans, or those 
 exceeding, say, four hundred (400) feet, the truss depth at outer hips 
 should be about one-fourteenth (3^) or one-fifteenth (^) of the total 
 span length. The truss depth at the inner hips should generally be from 
 one-ninth (J) to one-tenth (^) of the total span length; and when 
 towers are used, their height should generally be from one-sixth () to 
 one-seventh (^) of the span. Of course, the aesthetic features of the 
 design should govern greatly the determination of all these depths; and, 
 fortunately, any moderate change in them does not affect materially 
 their economics. 
 
 In swing spans it is evident that, as far as is consistent with safety, the 
 diameter of the drum for economy should be made as small as possible, 
 not only because this effects a saving of metal, but also because it reduces 
 the diameter, and therefore the cost, of the pivot pier. For spans of mod- 
 erate length and width there is generally a small economy in centre- 
 bearing swing-spans over rim-bearing ones, especially as the former some- 
 times permit of smaller pivot piers, but the difference is often inconsid- 
 erable. There is a limit to the size of centre-bearing swing-spans due to 
 the objectionable feature of concentrating great loads upon small areas 
 and to the necessity in the case of very wide spans for excessively heavy 
 cross-girders. The question of economics between the two styles of swings 
 is one that has to be determined for each special case as it arises by pre- 
 paring actual estimates and not by a priori reasoning. 
 
 In respect to the economics of cantilever bridges the following may be 
 stated: 
 
 FIRST. The economic length of the suspended span is about three- 
 eights (f ) of the length of the main opening, but a considerable increase 
 or decrease of this proportion does not greatly change the total weight 
 of the metal. 
 
 SECOND. The most economic length of anchor arms, where the total 
 length between centres of anchorages is given, and when the main piers 
 can be placed wherever desired, is one-fifth () of the said total length. 
 By keeping the anchor arms short, the top chords may be built of eye-bars, 
 provided that, with the usual allowance for impact, there is no reversion 
 of chord stress; and this effects quite an economy of metal. But it is 
 conceivable that cases might arise where, from danger of washout of 
 
 30 
 
falsework, eye-bar top chords would be objectionable; hence this method 
 of economizing must be used with caution. 
 
 THIRD. In respect to the economic length of anchor-span in a succession 
 of cantilever spans, it may be stated that within reasonable limits the 
 shorter such anchor-spans are the greater will be the economy involved; 
 but, generally, navigation interests will prevent their being built as short 
 as might be desired. If permissible, they may be made so short that, 
 as in the case of anchor-arms, eye-bars may be used for the top chords, 
 thus effecting a decided economy of metal, although shortening the anchor- 
 span increases proportionately the stresses on the web members and the 
 weights thereof. 
 
 The question of what is the economic limit of length of simple-truss 
 spans as compared with cantilevers is still a mooted one. Professors 
 Merriman and Jacoby place it in the neighborhood of six hundred (600) 
 feet, but the speaker has had occasion to compare simple-truss spans of 
 seven hundred (700) and eight hundred (800) feet with the corresponding 
 cantilever structures, and has found the former more economic. The 
 continuity of cantilever spans in resisting wind loads lowers the require- 
 ment for minimum width from one-twentieth (^) to about one twenty- 
 fifth (^) of the greatest span-length, and hence, because of substruc- 
 ture considerations, gives an advantage to the cantilever type that in 
 certain extreme cases will more than offset its disadvantages of greater 
 weight of truss metal. 
 
 There are certain legitimate economies that may be employed in the 
 designing of cantilever bridges, among which may be mentioned the 
 following: 
 
 A. The wind pressure assumed in computing the erection stresses 
 may be taken lower than that given in the specifications for the finished 
 structure, provided that the full wind pressure would not overstress any 
 of the metal seriously or involve any risk of disaster during erection. 
 A stress of three-quarters of the elastic limit of the metal applied a few 
 times during erection would do no harm, and the chance of there being 
 in that limited time any wind pressure at all approaching in magnitude 
 that specified is very small. This lowering of the intensity of wind pres- 
 sure may be the means of avoiding, in a perfectly legitimate manner, 
 the increasing of the sections of a number of truss members because of 
 erection stresses; but such economizing should be done with caution after 
 a thorough consideration of its greatest possible effects. 
 
 B. A certain amount of metal can sometimes be saved by splaying 
 the trusses between the main piers and the ends of the cantilever and 
 anchor arms; but unless the amount thereof be fairly large, the extra 
 pound price of the metalwork in the cantilever- and anchor-arms due to 
 the said splaying may more than offset the value of the reduction. 
 
 C. A small economy may sometimes be accomplished by omitting 
 during erection from the cantilever portion of the structure all parts that 
 are not essential to its strength before the coupling of the cantilever ends 
 is effected, thus reducing the erection stresses a little. 
 
 D. Solitary piers or large pedestals under the main vertical posts 
 are sometimes just as satisfactory in every way as long, continuous piers, 
 
 31 
 
especially if a connecting wall of reinforced concrete between them be 
 employed. Generally they will be found to involve a large saving in the 
 cost of the substructure. 
 
 E. In very wide cantilever bridges it might sometimes be advisable to 
 adopt intermediate trusses so as to economize materially in the weight of 
 the floor-beams and a trifle in that of the trusses, also because of the con- 
 sequent reduction in dead load, but mainly so as to keep within reasonable 
 limits the sizes and weights of the pieces to be handled and thus economize 
 on the size of the traveler and the cost of the erecting machinery. On the 
 other hand, though, increasing the number of trusses is likely to increase 
 a little the percentage of weight of truss details; but where the sections 
 of members are large this increase would be small. In case the wind 
 stresses are an important factor in the proportioning of the truss members, 
 the employment of an interior truss or interior trusses might, by the 
 reduction in areas of chord sections, cause such relatively large wind 
 stresses on the chords of the exterior trusses that the additional metal 
 required to take care of them would offset all the saving obtained in the 
 ways just mentioned. 
 
 F. In long-span cantilever bridges the stresses on the truss members 
 that rest upon the piers should be divided among as many such members 
 as possible by using an inclined strut on each side as well as a vertical 
 post instead of carrying all the loads to the top of the latter by tension 
 members, as was done in the design of the ill-fated Quebec bridge. Again, 
 if a lowering of the inner ends of the cantilever arms be permissible, the 
 inclining of the end sections of the bottom chords to the horizontal will 
 take up a portion of the load that is carried to the pier and thus will 
 reduce the stresses on the vertical and inclined posts assembling there. 
 This last feature reduces also the total cost of the masonry by diminishing 
 the height of the main piers, and saves placing the tops of the trusses 
 at an abnormal height above the water. 
 
 G. If there be any choice between the riveted and the pin-connected 
 types of construction for any cantilever bridge, it is generally better to 
 adopt the latter, because, as cantilever bridges are usually employed for 
 long spans only, pin-connected work is the more suitable. Again, it is a 
 little lighter than riveted work, and therefore the dead load on the structure 
 would be somewhat less. On the other hand, the riveted construction 
 is so much more rigid than the pin-connected that it is preferable to 
 adopt it whenever the conditions permit; besides, in the riveted work it 
 is not necessary to stiffen any truss members for erection, although it 
 might be obligatory to increase a few of their sectional areas. 
 
 H. Very large compression members should be made of box section 
 so as to do away with latticing. This not only effects an improvement 
 in the design, but also saves some metal, although the details required at 
 the panel points to distribute the stresses from the cut cover plates tend 
 to offset the saving in weight of lattice bars and stay plates. 
 
 Questions of erection often not only affect the economic layouts of 
 crossings but also determine the character of the spans to be adopted. 
 For instance, if the danger from washout of falsework be great, either a 
 cantilever or a semi-cantilever structure may be better than one of simple 
 
 32 
 
spans, or a pin-connected structure may be preferable to a riveted one, 
 even if the computations of cost made upon the basis of good luck in 
 erection indicate that the contrary is the case. Again, the chance of not 
 getting the substructure finished before high water or bad weather causes 
 a cessation or partial cessation of work might so affect the layout of spans 
 for a bridge as to increase materially the cost thereof; therefore, the 
 expense involved by taking precautions to avoid possible delay would be 
 in the nature of true economy. 
 
 In the proportioning of main members of bridges, and even occasionally 
 in the detailing, small economies may be effected by choosing the regular 
 and least expensive sections. Plates and angles are at times cheaper than 
 channels or I-beams, and at other times more expensive. Z-bars are 
 sometimes higher and are always difficult to obtain. Deck beams are in- 
 variably high priced, and tees are generally so. Many designers are not 
 aware that I-beams over fifteen (15) inches deep cost one-tenth (^ ) of 
 a cent per pound more than those fifteen (15) inches and under in depth, 
 and that angles having one or both legs longer than 6 inches are subject 
 to the same increase. There is a long list of special prices, too, on very 
 small angles. Not infrequently it will be cheaper to use the larger of two 
 small angles, even though more weight be involved; and special angles 
 such as those of 7 by 3^ in. section are always more expensive than the 
 standards, besides being more difficult to obtain. Current prices of the 
 various sections are to be found in Engineering News the first of each 
 month. Since the organization of the United States Steel Corporation, 
 the variations in pound prices of the numerous shapes of bridge metal in 
 this country are less than they used to be; but they are still sufficient to 
 make a material difference in the cost of structure: whereas, for Canadian 
 and other foreign work, very large differences may be created by the 
 selection of the material, owing to the variation in the customs duties. 
 It behooves the expert bridge designer to keep posted concerning varia- 
 tions in metal prices and import duties for the different sections. The 
 Bethlehem Steel Company manufactures, by means of a combination of 
 vertical and horizontal rolls acting simultaneously, some special sections 
 for I-beams that are exceedingly light for their strength; and, although 
 the company asks a small extra price for such sections, it generally proves 
 economical to employ them. 
 
 The duplication of a whole structure, or any parts thereof, effects a 
 large proportionate saving in the shop. Of course, if two spans or other 
 units can be made alike, entire groups of drawings are saved; and it is a 
 large part of the function of the detail shop draftsman to duplicate in- 
 dividual parts and to group partially-unlike members. By duplication, 
 in addition to a saving in drawings, there is a saving of templets, a saving 
 of shop supervision, a saving of the writing of shop bills, a saving of making 
 extra material lists, a large saving in errors, and a considerable saving in 
 the field due to the avoidance of loss of time in the selection of the proper 
 parts; for if there is much duplication, there is much more possibility of 
 the right parts being at hand. Duplication extends into very small details; 
 in beam work the end connections are made alike, and instead of being 
 shown on the drawings, their numbers only are given. Likewise the tem- 
 
 33 
 
plets for such end connections are made permanent; and they, too, are 
 referred to only by number and are used over and over again. On large 
 structures, batten plates, lattice bars, and other similar and oft-repeated 
 elements can be duplicated with great advantage. For instance, identical 
 lattice-bars save the resetting of the gauge on the lattice-bar punch, and 
 also the labor of selecting in assembling the material, besides considerable 
 expense in handling. It may at times require more material to duplicate 
 the parts of a structure, and yet it may result in a net saving in the 
 cost of construction; for, although the metal be ordered by the pound, if 
 the evidence of duplication of shopwork is made clear in the drawings sub- 
 mitted to bidders, a lower pound price will be named. 
 
 Blacksmith work of any kind is always the most expensive work in a 
 bridge shop, and it should be avoided to the utmost, not only because it is 
 not commonly well done but also because it costs heavily in the drawing 
 room, in the templet room, in the forge shop, and in punching, fitting, 
 and assembling. If forging is essential, it should be done in duplicate as 
 much as possible, so that dies may be made. 
 
 There is a small economy or the reverse involved in the crimping of 
 stiffening angles for plate-girders; and the officers of the different bridge 
 shops have widely varying ideas as to whether it is better or not to crimp 
 them. The economy will depend upon their strength and the amount of 
 offset, for the question involved is whether the cost of crimping the ends 
 does or does not exceed that of furnishing and putting in the filling plates. 
 The cost of the freight on the filling plates is often the determining factor 
 in settling whether it is finally more economic or otherwise to crimp stiff- 
 ening angles, and this feature of the question should be borne in mind by 
 the designer. This matter of cost of freight and other transportation of 
 metal to bridge site applies to the design of a bridge as a whole as well 
 as to the question of crimping. 
 
 There is often a material difference between the lightest possible bridge 
 and the most economic one, not only on account of the reduction of cost 
 of fabrication but also because of that of erection; and the designer, in 
 order to obtain the best possible results for all cases, must be well posted 
 on all the important details of both shopwork and field work. He should 
 know almost instinctively what is easy and what is difficult to manufac- 
 ture and to erect; and especially should he recognize when rivets can and 
 when they cannot be driven by the various kinds of apparatus used in 
 shop and field. 
 
 In the design of new bridges to replace old ones, the erection should be 
 given full and thorough consideration, since a large amount of the labor 
 of replacing the old structure under traffic may be saved if the new one 
 have panels of such length as not to interfere with the metalwork of the 
 old bridge. There are many other ways in which advantage may be gained 
 by thoroughly considering the erection at the time the new structure is 
 designed, such, for instance, as the supporting of the old stringers on ad- 
 vantageously located falsework until the new girders can be placed, and 
 the shipping of the plate-girder spans riveted up complete instead of re- 
 quiring that they be assembled in the field. 
 
 In all work of designing, the cost of the materials at the site should be 
 
 34 
 
studied very carefully, since local prices will often enable the designer to 
 effect a great saving. Where the work is scattered over a wide field, the 
 matter of cost of materials becomes exceedingly important and often 
 changes the type of the structure. For instance, in designing a highway 
 bridge for the Western Coast, it should be remembered that steel stringers 
 become very costly as compared with the lower-priced wooden stringers 
 of that country. The opposite conditions obtain in the eastern part of 
 the United States. The prices of gravel for concrete work, or of very 
 cheap stone, may affect the type of piers employed. The engineer should 
 know markets even better than the contractor, but commonly he does 
 not, and he will often demand an expensive material where a cheaper one 
 would serve his purpose quite as well. Rough averages of prices per unit 
 in place are very apt to produce flaws in the economy of a design. 
 
 There is an economic feature of bridge building that is worthy of special 
 mention, in that it effects a large saving in first cost, maintenance, and 
 repairs, often for a number of years. It is the designing of cantilever 
 brackets to carry in the future wagonways, footwalks, and even street 
 railways, and omitting putting them in until required, but providing all 
 the rivet-holes for the future connections. In such cases, of course, the 
 trusses must be made strong enough to carry the additional live and dead 
 loads, and the counterbracing must be figured for both the future and the 
 immediate dead loads. 
 
 A question sometimes arises as to whether it is more economic to sup- 
 port a pavement on buckled plate or on reinforced concrete. The latter 
 is cheaper for trestles and short spans, but not for long ones. However, 
 the deterioration of the buckled plates, due to moisture and smoke fumes, 
 should receive adequate consideration. Moreover, the latest experience 
 shows that very heavy concentrated live loads are liable to spring the 
 buckled plates and break up the paving. 
 
 Some of the most modern problems in bridge economics are those due 
 to the advent of reinforced concrete construction. For instance, in high- 
 way bridge building there arises the general question as to whether it is 
 advisable to adopt reinforced concrete or steel; and for spans under one 
 hundred feet in length, when due consideration is paid to the factors 
 of maintenance, depreciation, and repairs, the former will usually be 
 found the more economic. In the future this limit of span-length for 
 economy will certainly continue to increase; and probably even today 
 it has been passed in some localities. 
 
 Another problem is whether in reinforced concrete construction it is 
 preferable to adopt the arch or the girder type. Unless the spans are 
 quite long, the latter will generally be the cheaper, but the former is the 
 more aesthetic, although by curving the bottoms of the concrete girders, 
 as was done on the Twelfth Street Trafficway Viaduct in Kansas City, a 
 very pleasing effect can be secured. 
 
 Another economic problem is whether to adopt a wooden or a reinforced 
 concrete floor in a steel highway bridge; and, when danger from fire, cost 
 of maintenance, etc., are considered, the decision should invariably be in 
 favor of the permanent construction. 
 
 Since the late occurrence of partial destruction by fire of several large 
 
 35 
 
highway bridges carrying creosoted block pavement resting on creosoted 
 planks, the question has arisen as to how much more it would have cost 
 to rest the pavement on reinforced concrete. The layman has an idea 
 that the amount is very small, being merely the difference between the 
 value of the reinforced concrete slab and that of the creosoted planks; 
 but such is far from being the case, for the large difference between the 
 weights of the two bases adds materially to the dead load that has to be 
 carried by both the floor system and the main girders or trusses. 
 
 In the case of a steel viaduct, the question sometimes comes up as to 
 the economics of making the bents of reinforced concrete instead of steel ; 
 and for heights not greater than forty or fifty feet the concrete is likely 
 to win; but with braced towers the steel will generally prove the cheaper. 
 In solitary bents of reinforced concrete attention must be paid to the 
 bending effect of longitudinal thrust, and this is likely to prove an im- 
 portant factor in the determination of the economics of the layout. 
 
 There is an economic question to which, as yet, but little attention has 
 been paid, viz., the comparative costs of cantilever andsuspension bridges. 
 Until 1911 nothing of any value had been published concerning the length 
 of span at which a suspension bridge becomes cheaper than a cantilever, 
 each bridge specialist having had a vague idea of his own concerning the 
 question. The speaker for years has believed the dividing length to be in 
 the neighborhood of 2,000 feet, but has recognized that it will vary con- 
 siderably for different crossings on account of the governing conditions. 
 If the question were one of superstructure alone, it would readily be capable 
 of solution, but the substructure plays an exceedingly important part 
 therein. Dr. Steinman places the dividing span-length (based solely on 
 economic reasons) between cantilever and suspension bridges at about 
 seventeen hundred (1,700) feet; but certain assumptions differing from 
 his concerning schedule prices and other ruling conditions would have 
 increased somewhat this limit. 
 
 The economic depth for stiffening trusses of suspension bridges has 
 been determined theoretically by Dr. Steinman. He finds that it is about 
 one-fortieth (^) of the span, and states that this is somewhat higher 
 than the average of past practice, probably because most designs have been 
 a compromise between the demands of economy and those of aesthetics. 
 In his opinion, the Williamsburg Bridge, which is the only long-span 
 structure conforming to this economic ratio, is marred in appearance by 
 the excessive depth of the stiffening trusses. This limit does not strike 
 one as being very high, though, considering the fact that the trusses are 
 generally through ones and that they must provide a clear headway 
 ranging between twenty and twenty-five feet. If twelve hundred feet 
 be taken as the minimum span-length for which it would be legitimate to 
 consider the adoption of a suspension bridge for railway traffic, the eco- 
 nomic truss depth would be thirty feet, which is a little shallower than 
 it is practicable to adopt for a double-track bridge with floor-beams and 
 portal bracing that have ample depths for rigidity. A serious objection 
 to employing shallow deck stiffening trusses is their unsightly appearance. 
 All things considered, it is generally advisable to make the truss depth 
 
 36 
 
as shallow as the governing conditions will allow, provided that the eco- 
 nomic depth be not varied from too radically. 
 
 The inferior limiting ratio of distance between central planes of stiff- 
 ening trusses to span-length has not yet received due attention by engi- 
 neering writers. The speaker is of the opinion that it ought to be about 
 as one is to thirty, that for simple spans being as one is to twenty. There 
 are two good reasons for placing a minimum limit to this ratio, viz., to 
 avoid vibration and to make the various compression chords, which, in 
 a way, form one long strut of the same length as the span, have a reason- 
 able ratio of length to radius of gyration. For the thirty-to-one limit the 
 ratio of length to radius of gyration would be about sixty, which is well 
 within the bounds of good practice in strut proportioning. 
 
 The economic cable-rise for many years has been recognized as vary- 
 ing from one-tenth to one-eighth of the span length. For bridges in which 
 the side spans are without suspenders, Dr. Steinman finds that it is about 
 one-ninth of the main span, and for those in which the side spans are 
 suspended from the backstays it is about one-eighth thereof. 
 
 The number of arch bridges built up to the present time is compara- 
 tively so small, and the economic studies thus far made on arches have 
 been of such an approximate character, that but little reliable information 
 concerning the comparative economics of the various types is available. 
 There is a general impression that the smaller the number of hinges the 
 greater the economy, but there are conflicting opinions concerning that 
 view. Again, it is probable, but not yet proved, that for exactly similar 
 conditions of layout and loading a cantilever-arch bridge is a little less 
 expensive than an ordinary arch with two flanking simple spans. Finally, 
 the three standard kinds of ribs for fairly long spans in the order of their 
 economy are generally supposed to be the spandrel-braced, the braced- 
 rib, and the solid-rib types; but differences in the existing conditions at 
 crossings may vary this order in certain cases. 
 
 Another economic question in bridge engineering that has arisen of 
 late years is the economics of movable spans, or the choice for any crossing 
 between the swing, bascule, and vertical-lift types. The settlement of 
 this question is by no means an easy matter, for it will depend greatly 
 upon the special conditions affecting the particular crossing under con- 
 sideration. When the swing-span type is pitted against either of the 
 others, the first point to determine is what proportionate length of single 
 opening is equivalent to the two openings afforded by the rotating draw. 
 This is a matter of personal opinion, and even in one man's mind it might 
 vary materially for different cases. Under ordinary conditions, the speaker 
 believes that a single clear opening twenty-five (25) per cent greater than 
 either of the clear openings afforded by the swing type will give equally 
 good or better facilities for navigation, and that under the worst possible 
 conditions the excess percentage need not be more than forty (40). Un- 
 fortunately, though, neither the speaker nor the designer of the bridge 
 under consideration has anything to say about deciding this point, be- 
 cause the court of last appeal is always the War Department. If that 
 department deems that the clear opening or openings suggested by the 
 designer be insufficient, it has no hesitation whatsoever in saying so and 
 
 37 
 
in compelling the petitioner for approval to increase the said clear open- 
 ing or openings as much as its engineers consider advisable. Up to the 
 present time the War Department has almost always accepted plans of the 
 speaker's in which the excess percentage referred to has been twenty-five 
 or even less; but its having done so in the past is no reason for assuming 
 that its engineers will always be willing to recognize that percentage as 
 their maximum requirement. Accepting this settlement of the question 
 as fixed, it is practicable to compare swing spans with bascules and vertical 
 lifts. 
 
 In most cases when swing spans and bascules are compared, the result is 
 either a stand-off or more or less in favor of the bascule. The conditions 
 would be unusual where the swing proves to be much more economic for 
 instance, where the deck is very close to the water, thus necessitating a 
 well or wells for receiving the counterweighted end or ends of the bascule. 
 In almost no practicable case is the swing materially more economic 
 than the vertical lift, unless, perchance, the opening be very narrow, the 
 vertical clearance very great, and the depth of the bed rock small a 
 most unusual combination. In almost every case of comparison which 
 has occurred in the speaker's practice the vertical lift has proved less 
 expensive than the rotating draw. 
 
 Considering now bascules and vertical lifts, in most cases the economic 
 comparison favors the latter type. It always does so if the vertical clear- 
 ance is not in excess of fifty or sixty feet. If the clearance be the usual 
 one for ocean-going vessels, viz., 135 feet, the cost of the bascule and that 
 of the vertical lift will be equal for clear openings of about one hundred 
 feet or, in extreme cases, one hundred and twenty-five feet. The longer 
 the movable span, the closer the deck to the water, the deeper the bed- 
 rock, or the smaller the required vertical clearance, the greater will be 
 the comparative economy of the vertical lift. 
 
 As before indicated, the treatment of the economics of bridge designing 
 has been made much more elaborate and exhaustive than that of any 
 other specialty. For this there are four reasons, viz. : 
 
 FIRST. It is in the lead alphabetically on the list of specialties dis- 
 cussed. 
 
 SECOND. The science of bridge design has been more deeply and sys- 
 tematically studied than that of any other branch of engineering. 
 
 THIRD. It is deemed advisable to give an example of the thorough 
 treatment of economics in at least one engineering specialty. 
 
 FOURTH. Bridge engineering is the one specialty for which the speaker 
 feels capable of writing a truly exhaustive treatment of the question of 
 economics. 
 
 For these reasons he trusts that his hearers will pardon him for taking 
 so much time for the detailed discussion of "bridge economics". 
 
LECTURE III 
 
 CITY PLANNING* 
 
 The salient feature of economics in design and construction, so far as 
 engineering is applied to city planning, may be said to lie (as in other 
 engineering work) in a more or less accurate adaptation to purpose. In city 
 planning, the engineer endeavors to determine, for example, the width 
 which any street ought to have, so that it shall not wastefully be made 
 wider than necessary, nor, on the other hand, shall it prove too narrow 
 to perform properly the traffic function which pertains to it. He deter- 
 mines whether it shall be a traffic artery, a secondary street, or a purely 
 domestic street. In so doing he is able to determine not merely its proper 
 width, but also the strength and the character of the pavement it should 
 have, and the relative allotment of space to roadway, sidewalks, etc. 
 
 The districting of the city for different uses, the control of building 
 heights, and many other phases of city planning that have as their ulti- 
 mate object the possibility of greater adaptation to purpose, are economic 
 considerations, which often are of paramount importance. 
 
 DAMsf 
 
 The following are some of the salient economic questions in the design- 
 ing and building of dams: 
 
 Should dams be of earth or masonry? 
 
 If of earth, should there be a concrete, a puddle, or a soil core, or none? 
 What slopes should be used on upstream and downstream faces? What 
 pavement or other protection on the slopes? How should the earth be 
 compacted? 
 
 If of masonry, should the dam be curved in plan or straight? This will 
 depend upon the nature of the site, the length of structure, and other 
 numerous conditions. Should it be of concrete, or cyclopean, or rubble? 
 Should it be massive, i.e., solid construction, or of the reinforced, hollow 
 type? If of concrete or cyclopean masonry of the solid type, should it be 
 built in forms or faced with pre-cast concrete blocks, or faced with stone? 
 What margin of safety should be provided? This will depend upon the 
 importance of the water impounded by the dam, the risk to life and 
 property below, and the available funds, as well as other considerations. 
 
 All these are economic features of importance that affect the designing 
 and construction of dams. 
 
 ELECTRIC RAILWAYS 
 
 In the "Proceedings of the Engineers' Club of Philadelphia" for July, 
 1914, there is a paper by E. P. Roberts, Esq., C. E., entitled "Reporting 
 on Public Service Properties", in which is treated in great detail the sub- 
 ject of the economics of electric railways. As no better presentation 
 
 *Data furnished by Chas. Mulford Robinson, Esq., C. E., professor of civic design 
 
 in the University of Illinois. 
 tData furnished by Alfred D. Flinn, Esq., C. E., deputy chief engineer of the 
 
 Board of Water Supply of New York City. 
 
 39 
 
thereof could well be made, that portion of the paper relating to the said 
 subject, is reproduced nearly verbatim as follows: 
 
 General Survey 
 
 First, obtain a bird's eye view of the territory. To secure this, make 
 a preliminary study of all available maps, including topographical, and 
 note the general location of the proposed road, the location of the terri- 
 tory which apparently might be served, and such factors as might seem 
 until definite information is obtained, to restrict or to enlarge the territory 
 served, to a greater degree than would be the case if it were based upon 
 a strip two or three miles on each side of the road. An arbitrary assump- 
 tion of uniform width of territory served is misleading. Location of rivers 
 paralleling the route, high ridges or hills near the right-of-way, other 
 railroads, either paralleling or at an angle to the proposed road, and other 
 physical and transportation features all affect the ease of access to the 
 road, the traffic which should be secured, and the service which should be 
 offered. 
 
 Industrial Developments 
 
 Having in mind a possible general location, then some preliminary 
 knowledge of the characteristics of the territory is helpful before going 
 over the route. 
 
 What is the general character of the industries? Why did they develop? 
 Upward or downward tendencies? What probable future? Can the 
 proposed road help the development? 
 
 Mining fluctuating in value to an electric road. 
 
 Manufacturing less fluctuating in value to an electric road, but unless 
 diversified, quite variable. 
 
 Agricultural usually less tendency to fluctuation, but depends some- 
 what upon nationality of farmers; generally a farming community spends 
 less money for unnecessary riding than does a mining or a manufacturing 
 community. 
 
 Study census reports showing growth (or decrease) of population. 
 School, voting, and other records stating population, etc., can be studied 
 later. 
 
 Note the characteristics and the tendencies of growth of the principal 
 terminus. 
 
 Of secondary terminus. 
 
 Of intermediate territory. 
 
 Note direction of existing railroad traffic. Why have the roads such 
 directional location? Existing business and social relations have built 
 up a certain direction of travel; and if the proposed road does not serve 
 such existing traffic tendency, what reasons are there for presuming that 
 the direction of movement can be changed? Make note of this to ascertain 
 more accurately later. It requires exceptional conditions to deflect 
 existing directions of travel. 
 
 The location of an existing road may have resulted from either through 
 or local traffic conditions. If the former, and local conditions make a 
 cross-country road desirable, then the traffic condition for the proposed 
 
 40 
 
road may be excellent, but, in this, as in every other matter, all state- 
 ments must be carefully weighed, and the facts must be ascertained by 
 investigation. 
 
 Inspection Of Route And Territory 
 
 Being now prepared to appreciate what is seen, a rapid trip over the 
 route is advisable, but not giving too much attention to detail, and not 
 reaching definite decisions. It will be time enough later to consider the 
 equivalent of 5-ft. contour lines: 50-ft. ones are sufficient at this stage. 
 During such a trip, intelligent and applicable questions can be asked, and 
 the answers recorded, but not necessarily digested (and certainly not 
 evaluated) until later. Frequently, printed forms can be left with bankers, 
 secretaries of chambers of commerce, etc., to be filled in and mailed, or, 
 preferably, collected and discussed on a return trip. 
 
 A return trip can next be made and somewhat more leisurely, and 
 giving more attention to details, topography, character of soil, width of 
 rivers, heights of banks and of high water, character and growth of indus- 
 tries, crops (gross and per acre) ; also probable effect of the proposed road 
 on the character of crops, present routing and market, population, growth, 
 and characteristics. Industrial and sociological information of all kinds, 
 bank reports, building loan reports, etc., all are important. In each case 
 comparative statistics extending over a period of years should be obtained 
 tendencies and direction of growth, and especially of decay, should be 
 noted and the reason ascertained. 
 
 Present traffic and reason for traffic should be noted. How much of 
 the existing traffic will the proposed road obtain? Probably little, if any, 
 of such traffic as originates or terminates beyond its terminals probably 
 a large part of that which is local between such terminals. 
 
 From information as to amount and direction of traffic and knowledge 
 of general conditions affecting cost of construction, and having considered 
 strategic position, then a tentative location can be considered. If the 
 country is rather rough, a survey of one or more routes may be advisable; 
 if it is comparatively level, the survey may be postponed. When to make 
 survey depends on the time available, the season of the year, and other 
 factors, including the advisability of appearing to be busy, and of survey- 
 ing more than one route in order to obtain interest and competition. 
 This is about the only time when anything will be "given" to the road. 
 
 Tentative Plan 
 
 The tentative plan will be based on such ruling and maximum grades 
 as the engineer's experience indicates to him will probably prove, after 
 further examination, to be about right, considering the magnitude and 
 direction of traffic, topography, etc. Carried along with consideration 
 of locations, grades, etc., will be preliminary studies of the equipment 
 which will be necessary to handle the traffic, of the character of service 
 best fitted to the conditions, and of the general type of equipment best 
 suited to the service to be given. 
 
 Tentative train sheets should be prepared, and the comparative advan- 
 tages and disadvantages tabulated. Effect on platform charges (exceed- 
 
 41 
 
ingly important), effect on total and maximum peak power (as to each 
 substation and as to power house), location of passing points, relation of 
 the same to grade, meeting at central points in town, and whether ad- 
 visable or not, and other items should be duly considered. 
 
 The location of power house and sub-stations, of car shops, etc., re- 
 quires careful consideration. 
 
 The business probably obtainable for each class of service passenger, 
 express, freight, mail should be estimated on an annual basis, and also 
 monthly. In some cases, the sale of power and light may be contemplated, 
 but these items should be separated from receipts from railroad operation. 
 The probable rates obtainable, the expense of operation, including finan- 
 cial and all charges, the total investment and the net income for the 
 second, fifth, and tenth years of operation (or some other future periods) 
 must be predetermined with the greatest care. 
 
 Modification 
 
 The next step is to consider each general feature and then each detail 
 of each general class and ascertain what changes could be made, and the 
 net result, i. e., the effect on dividend. 
 
 Affecting Factors 
 
 A careful study should be made of the past history, the present develop- 
 ment, and the tendencies of the territory; and these should be considered 
 with reference to the probable effect on the magnitude and the character 
 of future growth. 
 
 The rules and the apparent tendencies of the decisions of the Interstate 
 Commission and of the Public Service Commission having jurisdiction 
 should be investigated. 
 
 Not only should location, construction, and equipment be considered 
 with reference to the traffic "in sight", but also with reference to the 
 development of the territory, including the possibility of assisting in such 
 development; and, in the latter connection, the character of construction 
 and of equipment which will be most desirable if such development is 
 obtained. 
 
 The history of the existing transportation companies serving the same 
 territory should be noted, also the policies or tendencies of the officers, 
 as, for example, whether they have fought or cooperated with other electric 
 railroads along their lines. 
 
 Profit Or Loss 
 
 Profit or loss depends upon the difference between two almost equal amounts. 
 
 A very small percentage of difference in receipts or expenses will make 
 a large percentage difference in the amount available for dividends. 
 
 Location, including terminal facilities, will largely affect the gross 
 income and also the cost of construction. The character of construction 
 and equipment somewhat affects the receipts, and largely affects the 
 operating expense, including maintenance, depreciation, and accidents. 
 
 Importance Of Careful Preliminary Investigation 
 A slight change in location may favorably or unfavorably affect con- 
 
 42 
 
structi on-cost and gross and net income, therefore, practically speaking, 
 it is impossible to give too much time and expense to a careful preliminary 
 investigation. 
 
 The latter will frequently indicate that, as to the immediate future, 
 certain locations will cost a comparatively small amount, and that such 
 grades as are economically advisable for the traffic immediately in sight 
 can be constructed at slight expense, also that there will be a minimum 
 expenditure for bridges and an avoidance of grade crossings of other 
 railroads or of highways. It may be possible that such a location is also 
 advisable as to the more distant future, including strategical position 
 with reference to business competition. If the grades, bridges, and trestles 
 can be so modified later as then to obtain a road having grades desirable 
 for such future traffic, the location may be advisable. Probably, how- 
 ever, such will not be the case as to at least a portion of the route; and the 
 future must always be considered. 
 
 The Future 
 
 Considering the future is not, however, equivalent to building for the future. 
 Planning for the future is advisable, but expending capital in order to 
 provide for the distant future requires careful consideration. It might 
 be better to place such money in a sinking fund, rather than in unpro- 
 ductive construction. Such sinking fund is usually a theoretical con- 
 sideration. The more usual consideration is, "Can such present unneces- 
 sary expenditure be saved and the total cost reduced, and thereby the 
 proposition be made more attractive to capital?" Steel bridges vs. 
 wooden trestles are simple examples of such consideration. Future 
 changes of grade will require (at least usually) a greater total expenditure 
 than if the roadbed were originally constructed at such final grade, but, 
 nevertheless, the interest saved is always important and may be vital. 
 
 Change in location is always expensive. When the road is proposed, 
 much of the right-of-way has little value; and a skillful promoter can 
 sometimes obtain right-of-way in a new territory for a comparatively 
 small amount. When, however, the road develops the territory, then 
 land becomes worth more to the owner, and is likely to cost the railroads 
 on the basis of even a greater percentage of increase. 
 
 The general result is that, to a considerable degree, the design and more 
 especially the construction which make provision for the future should be 
 mainly in connection with such items as will require a far greater total 
 expenditure when in the future the same are modified or reconstructed 
 than if originally so constructed. Right-of-way, and especially terminal 
 facilities, are free from maintenance and depreciation; and to change or 
 add to them in the future is very costly. On the other hand, such items 
 as ties, poles, trestles, minor buildings, and rolling stock, require renewal 
 in a comparatively few years and are largely independent as to their 
 functions. Usually they should be designed with reference to the near 
 future; and the character of replacement should be allowed to await the 
 development of the business. 
 
 System And Data Sheets 
 When making a preliminary investigation of the territory, a definite 
 
 43 
 
plan should be followed. Doubtless all engineers who are experienced in 
 such matters prepare data sheets on which they note such things as they 
 consider important. It is very advisable to prepare general data sheets, 
 tabular forms, etc., at times of comparative leisure. When a specific 
 case is under consideration, the forms prepared are liable to be affected 
 by special conditions and thereby lose general applicability and con- 
 venience for comparison. 
 
 The general character of information desired can be divided into two 
 classes: 
 
 First. That which in a general way always exists. For example: division 
 of territory into cities, towns, villages, rural, etc.; population and its 
 tendencies; public buildings; public service properties operated by the 
 city or by corporations; educational institutions; churches; theatres; 
 libraries; parks; fair grounds; banks and building and loan associations; 
 manufacturing establishments; wholesale and retail business houses; etc. 
 
 Second. Conditions of an unusual character, such as oil or gas wells, 
 exceptionally large state institutions, manufacturing plants with world- 
 wide reputation and having many employees, etc. 
 
 The unskilled observer, and sometimes even the skilled observer 
 occasionally neglects to check off his list; and he obtains quite complete 
 information relative to the unusual or striking and spectacular conditions 
 and omits some of the items in the first class. The result is that additional 
 money and time are required in order to obtain data, or else they are not 
 obtained. 
 
 Data 
 
 When obtaining data from individuals, considerable allowance must be 
 made. It is well known that locating the high-water mark of a stream on 
 the basis of the statement of the "oldest inhabitant" is very unwise. 
 Usually, information can be obtained from more than one source and the 
 advisable discount made; and thereby fairly accurate information can be 
 obtained as to practically all of the major non-technical factors relative 
 to the territory. Bank statements and talks with bankers are very helpful. 
 The country banker has a detailed knowledge of the crops, mortgages, 
 and points to which shipments are made, and as to all of the activities of 
 the rural communities; and his statement can be accepted as approxi- 
 mately accurate, especially if checked up in a few cases by the examination 
 of farms, etc. The conditions of the fences, buildings, &c., usually in- 
 dicate the facts as to mortgages. 
 
 The application of general statistics to a specific case may be helpful; 
 but it is always accompanied by the serious danger that figures may be 
 used which should not be applied to the case under consideration. 
 
 Statistics can be obtained as to roads in the same general territory, 
 and possibly having the same principal terminal town; and these should 
 be considered carefully. No statistics from any road should be applied 
 to the proposed road, unless the engineer has quite complete knowledge 
 as to the road from which the figures were obtained. No two roads are 
 exactly alike, and, as before stated, it must never be forgotten that a very 
 slight difference in the net receipts may make the difference between 
 profit or loss to the stockholders. 
 
 44 
 
ENGINEERING TEACHING* 
 
 This is a subject concerning which the economics are difficult to define. 
 Dr. Swain outlines them thus: 
 
 1. Engineering teaching should be done by men who have had prac- 
 tical experience, and also who have had some training in teaching and 
 psychology and who are in sympathy with the point of view of young 
 men. Moreover, and most important of all, they should be well-balanced 
 men, and not faddists. I am inclined to think that the teaching profession, 
 as a whole, contains more faddists and men of unbalanced views than does 
 any other occupation; and I consider that the teacher can do more for 
 his pupils by giving them sane and sensible points of view, methods of 
 attack, and clear conception of the possibilities of the subject studied and 
 its relation to other subjects, than by filling them up with technical 
 knowledge. 
 
 2. The teacher should aim first of all to teach his students to think 
 logically, clearly, and concisely. The great bane of teaching today is 
 that its object, in most cases, appears to be to give information. The 
 result is that it makes rule-of-thumb men. Many students, however, 
 seem to think that that kind of thing is what they come to school to get; 
 and it takes some readjustment of their point of view to make them see 
 that what they need more than anything else is clear thinking. For this 
 reason, what a man gets out of his college will depend more upon the teach- 
 ers with whom he comes in intimate contact than upon the subjects 
 which he studies. 
 
 3. Engineering teaching should consist of courses which are well 
 coordinated, so that there shall be a gradual and systematic advance from 
 one subject to another, without any more repetition than is necessary to 
 hammer the principles in. Some amount of repetition is desirable for 
 this purpose. One of the most difficult things is to procure the proper 
 coordination between engineering topics taught by the engineering depart- 
 ment, and other subjects, like mathematics, physics, etc., which are 
 taught by other departments. 
 
 HARBORsf 
 
 It is somewhat difficult to generalize upon the economics of harbor 
 construction, because every harbor has its own problems to solve, depend- 
 ing on class and quantity of freight and shipping, of railway approaches, 
 of climate, and of a dozen other contingencies. 
 
 It may, however, be premised that there is a solution for each individual 
 case, and that the economic development in any case must be found in a 
 thorough consideration of conditions. Such conditions in nearly every 
 instance will be found to be rapidly changing with increases in size and 
 draught of ships, necessitating longer docks and more commodious freight 
 storage. In Canada, especially, the very great increase in ocean freights, 
 demanded by the immense shipments of wheat from the Northwest, has 
 
 *Data furnished by Dr. Geo. F. Swain, professor of civil engineering at Harvard 
 University, and consulting engineer, also Past President of the American 
 Society of Civil Engineers. 
 
 tData furnished by Col. Wm. P. Anderson, chief engineer of the Marine and Fish- 
 eries Department of Canada, and Past President of the Canadian Society of 
 Civil Engineers. 
 
 45 
 
forced in Canadian ports rapid and vast increases in harbor accommo- 
 dation instance the ports of Vancouver, Prince Rupert, Port Arthur, 
 Fort William, Montreal, Quebec, Halifax, and St. John. 
 
 For the economical and successful development of a harbor, the first 
 essential is a comprehensive layout of the water-front as a whole, taking 
 advantage of all local factors, such as contour of shore, depth of water, 
 set of current, facility of railway approach, in order to secure the best 
 results. It may be laid down as a general rule that the best layout is to 
 provide wharves in parallel lines, at such an angle to the quay wall as will 
 allow easy railway approach and facilitate the entry of vessels to the docks. 
 
 In most harbors, sufficient provision has not been made in advance for 
 progressive deepening, and much waste has ensued in consequence of the 
 necessity of rebuilding for each increase in depth demanded by the deeper- 
 draught vessels. 
 
 The question of building wharves of timber or of more permanent 
 material is one that gives much thought to the engineer, and the decision 
 must depend on many factors. With the advance in cost of timber and 
 the cheapening of concrete processes the tendency is very general to use 
 concrete increasingly. It is often found to be good practice from the 
 score of economy to place timberwork cribs below low tide and finish 
 with concrete blocks or mass-concrete. 
 
 There are many problems yet to be solved in connection with the com- 
 position and placing of concrete. Many instances have occurred of the 
 disintegration of concrete by chemicals absorbed from salt water, and it 
 is also a question whether reinforcement in salt water is not liable to 
 corrosion. There is plenty of room for further study of all these problems. 
 In my personal experience I have seen a good deal of destruction of con- 
 crete quay walls, the bad disposition of the interior filling and the frost 
 forcing the walls out of alignment. 
 
 Sufficient consideration has in the past not been given to convenience 
 of construction of freight sheds and to vehicle and rail approach and for 
 handling freight. Generally, freight sheds should be so designed that 
 machinery can be used for loading and unloading into and out of them; 
 and so that transfer from rail to ship can be effected with the least possible 
 handling and truckage. The best means of accomplishing such aims must, 
 of course, vary with every shed and with every class of freight. 
 
 In modern harbors it is invariably a rule to separate rail transport 
 from other vehicle transport and so to arrange the approaches that the 
 one class cannot interfere with the other. 
 
 HIGHWAYS* 
 
 Concerning the economics of highway designing and construction, the 
 following data are taken from a letter of W. G. Harger, Esq., C. E. 
 
 The details of economic highway design are everywhere a local problem 
 depending on the available materials, climatic conditions, and traffic re- 
 quirements. I know of no one who has had enough personal experience 
 in the design, construction, and maintenance of the various types under 
 
 *Data fiirnished by W. G. Harger, Esq., C. E., engineer of the Commission of 
 Highways of New York State. 
 
 46 
 
different sectional requirements to pose as an expert over any extended 
 part of the country, except on very general lines. 
 
 The salient features which govern the cost of a highway system are 
 legislative and finance programs which provide the necessary money at 
 the proper time, an engineering design which at all times strives to use 
 local materials to advantage, and a constructing staff which insists on 
 good workmanship. 
 
 The financing of our New York State system of highways has never 
 been well worked out for either construction or maintenance; and what 
 applies to us, I believe, is true of a large percentage of cases. The per- 
 manent features of a highway improvement are the grading, drainage, 
 and foundation. The surfacing is temporary, even for the so-called 
 "permanent" types. Road improvements are generally financed by long- 
 term bonds; and no provision is made for construction renewals before 
 the original bonds expire. The rigid-pavement types such as brick, 
 asphalt, concrete, etc., need resurfacing in from ten to twenty years; the 
 macadams in from five to ten years. The ordinary maintenance for the 
 rigid types will run about $200 per mile per year with a resurfacing charge 
 of $10,000 to $15,000 per mile at intervals of about 15 years. The ordinary 
 maintenance on macadams is about $500 per mile per year, with a re- 
 surfacing charge of $4,000 to $6,000 per mile at intervals of seven to 
 eight years. The yearly cost of maintenance and renewals amounts to 
 approximately $1,000 per mile. Provision for this amount has never been 
 made, which circumstance results in a gradual deterioration of the roads, 
 and will finally occasion an unnecessarily large expenditure to put the 
 system back in good condition. Proper provision should be made for 
 maintenance and renewal, or else a large future waste is certain to occur. 
 A foresighted policy in this particular would save the community more 
 than would any engineering economics of the design. 
 
 The engineering design rests on the consideration of construction, 
 maintenance, and renewal costs. In discussing this problem most of 
 the current literature and most highway speakers emphasize and confine 
 economics to the selection of pavement type. This is a natural result of 
 the exploitation of various materials and patented processes. As a matter 
 of fact, our experience indicates that, for 75 to 80 per cent of the roads, 
 the final cost is not greatly affected by the selection of type, except as it 
 governs the use of local material. In general, the high and the low priced 
 pavements cost about the same, considering interest on first cost, main- 
 tenance, and renewals. What is saved on first cost is spent on maintenance. 
 
 The engineering economics of design are limited to a careful grading 
 and safe foundation design, utilizing local material; and to a selection of 
 the cheapest first-cost type of pavement of the general class required by 
 the traffic, i. e., a rigid type for very heavy traffic, and for all ordinary 
 roads any type which will utilize local materials to their best advantage. 
 On from 75 to 80 per cent of the mileage of most State systems, any 
 standard type of construction which is the cheapest in first cost will gen- 
 erally be the cheapest in the end. 
 
 The inspection of construction has more effect on the final cost than 
 has the design. On government work there is a great variation in the care 
 
 47 
 
and knowledge of the inspectors. Well-built macadams are much cheaper 
 in the end than poorly constructed brick or concrete pavements. 
 
 The problem of improving inspection is a difficult one, and the results 
 appear to be spasmodic. If good inspection is not reasonably certain, the 
 more-nearly-" fool-proof " macadams are the most economical designs. 
 
 INSPECTION* 
 
 Engineering inspection has two economic relations, first in its effect 
 upon the work inspected, and second in the actual conduct of the in- 
 spection. 
 
 It is inevitable that errors occur in the manufacture of materials and 
 in construction, irrespective of the question of intentional avoidance of 
 the requirements of the specifications. The later the discovery of such 
 errors in the progress of engineering work the more expensive is the cor- 
 rection, both in its own cost and in the cost of delay to the completion 
 of the work. It is, therefore, of prime importance that the manufacture 
 of material, the fabrication in the shops, and the erection in the field should 
 have all errors and departures from the specifications discovered and 
 corrected at the earliest possible moment. Competent inspection serves 
 not only to discover and correct such errors but also to aid the contractor 
 in avoiding them and to lead him to stronger efforts on his own part, when 
 he is well aware that such errors are certain to be discovered and the 
 responsibility brought back to him. Competent inspection can also 
 frequently suggest more expeditious or economical methods of manufac- 
 ture and thereby tend to economy. 
 
 The performance of inspection work has become somewhat of a specialty 
 and requires experienced and skilled men of a number so located as to 
 avoid, as far as may be, the expense of travel and the loss of time necessary 
 thereto. When the manufacture of engineering materials for a contract 
 is conducted at a number of different points, such work progresses at 
 approximately the same time and must be inspected by a number of men; 
 the manufacture may be intermittant, requiring more men at one time 
 than at another; and the greatest economy is accomplished through an 
 organization of experienced inspectors who are able to undertake the work 
 of inspection (each at his location) for several parties at the same time. 
 With such an organization skillfully handled, there is a minimum amount 
 of lost time and expense in traveling, with a corresponding reduction of 
 cost. 
 
 The processes of manufacture of material are so highly developed that 
 large output with minimum handling and delay is essential to the success- 
 ful operation of the manufacturing plant. Properly to conduct the in- 
 spection under these conditions, it is essential that the inspectors be ex- 
 perienced not only in the line of work but also frequently with the indi- 
 vidual manufacturer's facilities and methods. The inspector must have 
 full knowledge of all details of manufacture and must know by previous 
 experience when his presence at any portion of the works is essential to 
 the best carrying out of his inspection. 
 
 *Data furnished by P. S. Hildreth, Esq., C. E., of Hildreth & Co., inspecting 
 engineers, New York City. 
 
 48 
 
The above remarks apply particularly to important engineering struc- 
 tures such as bridges, steel frames of large buildings, important machinery, 
 and the like. No branch of engineering requires more of the old-fashioned 
 quality of common sense and tact, thoroughness, and loyalty to the work 
 than does inspection. At best it cannot be entirely complete, nor can it 
 replace the requirement of contracts and specifications as to the essential 
 qualities of materials and workmanship; but it can always, if well done, 
 be of marked economic value in connection with the work itself and 
 frequently to the contractor. 
 
 MINING* 
 
 The business of mining consists in the extraction of valuable minerals 
 from the earth with the greatest possible profit. Like Gaul it is divided 
 into three parts. 
 
 1. Exploration or prospecting. The search for minerals. 
 
 2. Extraction of the ore from the ground. 
 
 3. Reduction of the mineral to a marketable condition. 
 
 With the exception of gold, all metals and minerals mined vary in value 
 from time to time; and mining operations should be adjusted so that the 
 maximum profit shall be obtained during a period of high prices. Copper, 
 lead, zinc, and mercury were sold in 1916 at double the minimum prices of 
 1914. Other minerals, such as petroleum, potash, borax, and nitrates, also 
 vary considerably in value from year to year. 
 
 Exploration, Prospecting, Or The Search For Minerals 
 
 Under normal conditions, the vast majority of mineral deposits through- 
 out the world are of too low grade to be worked profitably. Under any 
 circumstances, owing to the fact that we cannot see into the ground, the 
 work of prospecting and exploration is usually fruitless and carried on at 
 a loss. It is notorious that great and successful mining corporations 
 (mining copper, lead, or oil) spend very little of their funds on exploration 
 work searching for minerals, except in very favorable or well-proven dis- 
 tricts. Such companies prefer to purchase mineral deposits, even though 
 the price is high, after their discovery by other parties. This is a better 
 economic policy than to expend funds in a fruitless search. In any case, 
 the proportion of money invested in exploring for mineral deposits should 
 be very strictly limited, in order to avoid undue risks of losing the capital 
 invested. 
 
 In some deposits, such as coal, salt, iron, and sulphur, these risks are 
 not always so great; but, ordinarily, the costs incurred in searching for 
 deposits of gold, silver, copper, and lead are enormous. 
 
 The Extraction Of Mineral From The Earth 
 
 This problem is that of finding a method of extracting the ore at the 
 minimum cost. It varies enormously with the size of the deposit, with 
 its character and geographical location, with the grade of the ore, and 
 with numerous problems of administration, such as drainage, transpor- |J 
 
 *Data furnished by James W. Malcolmson, Esq., M. E., consulting engineer to the 
 Lucky Tiger-Combination Gold Mining Company, Kansas City, Mo., and 
 Mexico. 
 
 49 
 
tation, ventilation, and other factors. Where labor is high in price and 
 fuel cheap, as in the United States and European countries, labor should 
 be economized to the last degree; and machinery, explosives, and scientific 
 method of transportation should be utilized to the greatest possible extent. 
 In other countries where labor is cheap, fuel high-priced, and railroad 
 facilities poor, a different policy must be adopted; as money may readily 
 be lost by the use of machinery, especially if it be necessary to import 
 skilled labor to handle the equipment. All the factors in the problem vary 
 in every mining field; and it is only by careful study that the proper 
 economic plan of operation can be worked out. Conditions in Joplin, 
 Missouri, may vary so greatly from those in Clifton, Arizona, or in 
 Alaska, that an engineer successful in one of these fields often fails utterly 
 when transferred to another district.. 
 
 The mining of ore occurring in thin seams and worth $100 or $1,000 per 
 ton presents difficulties and economic problems very different from the 
 mining of immense deposits of copper containing values of $6 per ton or 
 coal worth $1 per ton. The extraction of oil at $1 per barrel or gas at 
 1 or 2 cents per thousand feet presents yet another class of economic 
 problems altogether different in character, although the underlying main 
 object is always the same viz., to earn a profit on the investment, and the 
 return of the capital invested before the deposit is worked out and ex- 
 hausted. 
 
 It is of interest to consider to what depths mining is economically 
 practicable. 
 
 Coal is mined in Belgium at a depth of 4,000 feet. Copper is mined in 
 Michigan from 5,300 feet in depth, and gold is mined in the Transvaal 
 from almost as great a depth. The problem of mining from great depths 
 is altogether an economic one, the difficulties met, the costs of hoisting 
 and pumping, the problems of increasing temperature and ventilation 
 being all engineering questions for solution. 
 
 Mining of any ore-deposit is a transitory business; and, by the time the 
 ore is exhausted, the work ceases and the mine is abandoned. The busi- 
 ness, therefore, has special economic risks to such an extent that it is 
 generally recognized as an extra hazardous financial operation, and is 
 often frowned upon by so-called conservative capitalists. At the same 
 time it can readily be demonstrated that the whole structure of our 
 civilization rests on the mining industry. Without coal, iron, copper, 
 and other minerals we should be back once more in the stone age. 
 
 Reduction Of The Mineral To A Marketable Condition 
 
 The methods of reduction vary so materially with the different ores 
 and the different localities where they are mined that it would be almost 
 impracticable either to systematize them or to discuss their economics, 
 hence the attempt will not be made. Good judgment and common sense, 
 applied to each case as it arises, are the surest means of attaining an 
 economic method of reducing and concentrating ores. 
 
 50 
 
RAILROADING* 
 
 The subject of the economics of modern railroading is a broad and in- 
 tricate one, and deserves a full and elaborate treatment by a master hand; 
 but, unfortunately, none of the authorities seem inclined to write an 
 exhaustive treatise on the subject. Wellington's great work, "The Eco- 
 comic Theory of Railway Location", is now out of date, and should be 
 replaced by a modern book covering the entire ground. 
 
 The best that the speaker has been able to do with this subject for these 
 lectures was to obtain a few notes on railroad economics from two of the 
 highest American authorities; and these are presented herewith. 
 
 Mr. Holbrook writes: Safety of the road and of trains being assured 
 so far as possible, economy is of prime importance. This is true through- 
 out all the departments of the railroad organization. The civil engineer 
 is especially concerned with the economics which may be attained by 
 proper care in location, in construction, in maintenance, and in structures. 
 
 The location problem may be taken as typical. 
 
 The road must be located so as to insure that net earnings shall be as 
 large as possible. To do this: (1) Provide for the maximum possible 
 income by running the line to or through all important traffic points 
 which can reasonably be reached. (2) Provide for the smallest possible 
 expense by so locating the line that the sum of operating expenses and 
 fixed charges shall be a minimum. ("Operating expenses" as here used 
 include all expenses for operation and maintenance). 
 
 The procedure recommended by Wellington, which is probably the 
 safest and best, is to lay down first the cheapest line which will carry the 
 traffic with safety. This will be a relatively expensive line to operate, 
 and, probably, will not be the best (or most economical) line, but the 
 fixed charges for interest upon the construction cost will be small. Then 
 study this line in detail, and revise it only where the revision can be 
 shown to be economical in itself, reducing grades and removing more or 
 less of the curvature, distance, and rise and fall. In considering the 
 effects of these changes upon operating expenses, it is necessary to take 
 into account the results not only upon the cost of running trains, but also 
 upon the cost of maintaining structures. 
 
 By reducing the ruling grade we make it possible to handle heavier 
 trains, and therefore fewer trains are necessary. This results in a saving 
 (which may be very large) in operating expenses. 
 
 The reduction of curvature, distance, and rise and fall is of less financial 
 importance; but the effects are definite and of sufficient consequence to 
 warrant most careful study of the line, section by section and part by part. 
 
 The effects of each proposed change upon construction-cost and upon 
 operating-expenses are calculated, and the interest charge upon the in- 
 creased cost of construction is compared with the annual saving in cost 
 of operation. So for each of the proposed changes. 
 
 Other items enter into the problem, but these are the most important. 
 
 : Data furnished by Elliot Holbrook, Esq., C. E., valuation expert to the Union 
 Pacific Railway System, and Fred Lavis, Esq., C. E., consulting engineer to 
 the American International Corporation. 
 
 51 
 
Construction and maintenance problems might be discussed similarly. 
 Many of the problems involved are not special to railroad work, but some 
 of them, as track, signals, etc., are not met with elsewhere. 
 
 There are certain special questions of design where, as always, economic 
 considerations control; as, for example, in determining the proper size 
 and weight of rail for a certain line, the proper size and material for ties, 
 the use of special steels in track work (especially in frogs and switches), 
 questions involving the design of signal systems, the placing of passing 
 sidings to give the maximum capacity to the line for a given expenditure, 
 the design of yards and terminals, etc. 
 
 Mr. Lavis writes thus: A railroad is a machine, the product of which 
 is transportation. The type of machine which produces the finished 
 article at lowest cost is the most economical. The total cost of transpor- 
 tation is composed of two principal factors, the actual cost of operation 
 and the interest on the investment. The latter is governed, of course, by 
 the original cost of the line and its equipment. The cost of operation is 
 divided into four principal items: General expenses, Traffic expenses, 
 Cost of transportation, and Cost of maintenance, the latter two being 
 those in which the engineer is generally most interested. The Cost of 
 transportation is affected by Distance, Curvature, Rise and fall, and Rate 
 of ruling gradient. The cheapest line to operate between any two points 
 is a straight line of a uniform rate of gradient, provided this latter does 
 not exceed the reasonable limits of economical operation by adhesion 
 locomotives. 
 
 Deviation from a straight line involves greater distance and introduces 
 curvature, both of which increase the total resistance to be overcome by 
 the locomotive, and, therefore, increase the cost of operation. Deviation 
 from a uniform gradient introduces rise and fall. Within certain limits 
 this has little effect on the cost of operation, as the saving in power on the 
 down-grades offsets the additional power required to climb the up-grades; 
 but beyond these limits the stored momentum in the moving train is 
 destroyed by the use of brakes on the descending gradients, and the 
 additional climbs are added resistance. All stops increase the cost of 
 operation. 
 
 The rate of gradient is often of importance; and additional distance 
 may be justified to obtain a lower rate. The value of this item depends 
 largely on the volume and the kind of traffic; but, provided the amount 
 of the rise and fall is the same, it is by no means always the case that a 
 lower rate of gradient permits cheaper operation, if it involves greater 
 distance '(or even greatly increased cost of construction) to attain it. 
 
 A further item of importance involves the positive or negative values 
 of deviation due to the necessity of reaching centres of traffic. 
 
 The costs of maintenance depend partly on the natural wear and tear 
 due to the action of the elements, which affect in different degrees different 
 types of structures, that is to say, whether they are of wood, stone, or 
 iron and partly on the wear and tear due to the traffic passing over the 
 line, which amount depends on the volume of the said traffic. 
 
 52 
 
SEWERAGE* 
 
 Concerning the economics of his specialty of sewerage, Harrison P. 
 Eddy, Esq., C. E., writes as follows: 
 
 1. A fundamental economic consideration in the design and con- 
 struction of sewerage works is the provision which shall be made for the 
 future. The decision must depend upon an opinion of the rate of growth 
 and development of the community. This opinion must be based upon 
 a study of the many natural conditions, and of the history of other cities 
 similarly situated, and upon a consideration of the changes likely to take 
 place, due to the advancing age of the whole country, or the portion of 
 the country in which the community is situated. 
 
 2. The quantity of sewage for which provision should be made, must 
 be based not only upon present conditions, but upon a mature judgment 
 as to future conditions, as the requirements and demands of the public 
 are constantly changing and at present rapidly increasing. Too great 
 an allowance for future growth results in waste. Too small an allowance 
 will be equally disastrous. 
 
 3. Too great provision for the future may be followed by difficulties 
 in operation, resulting in unsatisfactory conditions or excessive operating 
 costs. 
 
 4. Provision for run-off during storms must be based not alone upon 
 rainfall and the estimate of the corresponding run-off, but also upon the 
 expenditure which the community can afford to make for the satisfactory 
 removal of storm water. It may well be that some communities can better 
 afford to be flooded occasionally, and even to pay damages from the public 
 treasury on account of such flooding, than to go to very large expense in 
 order to avoid such occasional difficulties. 
 
 5. In sewage treatment, economic considerations should play as im- 
 portant a part as in sewerage and drainage; perhaps even a greater part. 
 Here it is necessary to balance the advantages obtained against the cost. 
 The engineer should not be misled by aesthetic considerations which may 
 lead him to the conclusion that absolutely no sewage and no partially 
 treated sewage should be admitted to natural water courses. The expense 
 involved in attaining such an end may be entirely out of proportion to 
 the resulting advantages. 
 
 6. It is important to distinguish between conditions which are known 
 to be detrimental to public health, and those which are simply objection- 
 able on aesthetic grounds. A reasonable expenditure for the protection 
 of the public health should always be advocated. Nevertheless, such 
 expenditures should be balanced, and the funds available should be 
 expended upon those enterprises which will produce the greatest results. 
 For example, by a complete treatment of the sewage of a municipality, 
 the possibility of contracting typhoid by a few bathers, or a few persons 
 enjoying the water-way for pleasure purposes such as boating may be 
 avoided. A similar expenditure in contagious-diseases hospitals, in the 
 fight against tuberculosis, or in a number of other ways, may result in a 
 saving of many times the amount of sickness and death which might be 
 
 *Data furnished by Messrs. Metcalf and Eddy, consulting engineers, Boston, Mass. 
 
 53 
 
caused by allowing the untreated sewage to be discharged into the neigh- 
 boring water course. 
 
 7. It is important to preserve our natural resources. Every stream 
 or body of water has an economic value to the community. If sewage is 
 allowed to be discharged into such waters, in amounts which shall deprive 
 us of their use, we suffer an economic loss. It is, therefore, important to 
 measure these values and balance them with the cost of treating the sewage 
 to an extent necessary to maintain these natural resources in a condition 
 which shall enable us to take advantage of their values. In some cases, 
 it will prove economical to abandon the natural resources to the disposal 
 of sewage and industrial wastes. In other cases, treatment necessary to 
 preserve the waters in suitable condition for our use and enjoyment will 
 involve expense much less than "the value of the waters. 
 
 8. In industrial communities where liquid wastes must be disposed of, 
 other economic questions are introduced, such as the value of the indus- 
 tries to the communities in question, and the expense which may be requir- 
 ed of the industries, in the treatment of their wastes, without the danger 
 of driving them out of the community. As in the case of sewage disposal, 
 the value of the water-ways to the community must be off-set against the 
 cost of the treatment of the industrial wastes; and coupled with this bal- 
 ance must be weighed the value of the industry to the community. 
 
 WATER SUPPLY* 
 On this subject Alfred D. Flinn, Esq., C. E., writes as follows: 
 
 Replying to your letter of November 8, I am jotting 
 down below several more or less random questions which 
 occur in considering the economics of water works. I have 
 been unable to find time to attempt to classify them or even 
 to make the list at all complete. They are merely sugges- 
 tions which have occurred off-hand, and might be described 
 as "Some Examples of Problems Arising in Various Places 
 and under Various Circumstances in Connection with the 
 Economics of Water Works Projects". 
 
 Possible extension of system with growth of community 
 and provisions therefor; relative cost of each. 
 
 Pumping from wells versus supply from stream or lake by 
 gravity. 
 
 Pumping from a nearby source versus gravity supply from 
 a distant source. 
 
 Air-lift versus centrifugal well pumps. 
 
 Reciprocating pumping engines versus turbine pumps, in- 
 cluding cost of buildings and foundations. 
 
 Filtration of a nearby impure supply versus a more distant 
 supply of water of better natural quality. 
 
 A comparatively lower-cost supply of hard water versus a 
 more expensive soft water, including expenditure by mem- 
 bers of the community for soap, boiler compounds, etc. 
 
 *Data furnished by Alfred D. Plinn, Esq., C. E., deputy chief engineer of the 
 Board of Water Supply, New York City. 
 
 54 
 
Relative suitability and economy of cast-iron, riveted- 
 steel, welded-steel, and wooden pipes, depending upon 
 sizes, prices, feasibility of transportation, life, cost of re- 
 pairs, and local conditions of water, soil, climate, and elec- 
 trolysis. Economic sizes of pipes, considering probable in- 
 crease of consumption. 
 
 For large steel conduits, jacketing with concrete and 
 lining with cement mortar, thus greatly prolonging life and 
 materially increasing the hydraulic capacity, compared with 
 ordinary coatings and the roughness due to rivet heads, laps 
 at joints, and tuberculation. 
 
 Should very large steel pipes be shipped from the shop 
 completely formed and coated, or the plates rolled to the 
 proper radius and nested, to be riveted together in the field 
 and there protected by concrete and mortar or coated? 
 
 Should filters be of the slow-sand type or the rapid-sand 
 type? What rate of filtration should be adopted? If rapid 
 filters, what coagulant? How large should the individual 
 filter beds be, and how should they be grouped? 
 
 What building materials should be used for pumping 
 stations, gate-houses, and other buildings? 
 
 Should watersheds be owned outright and sources of pol- 
 lution removed, or should inexpensive patrols be maintained 
 to prevent the worst cases, and dependence be put upon the 
 purification of the water by filters? 
 
 Can the watershed selected as the source of supply be 
 best developed by one very large reservoir or by several 
 smaller reservoirs? 
 
 For aqueducts or large pipes, would a straighter and 
 shorter line, with tunnels and deep cuts, be cheaper than a 
 longer line of relatively light cut-and-cover construction, 
 with few or no tunnels? 
 
 Should|bottomsf andfslopes of impounding reservoirs be 
 stripped of vegetation and soil at considerable expense, or 
 should the money be expended for aeration and filtration? 
 
 55 
 
CONCLUSION 
 
 The speaker recognizes clearly the numerous faults and deficiencies of 
 his entire treatment of the subject of "Engineering Economics" in this 
 series of lectures; but he feels that he has done his best, considering all 
 the circumstances and the governing conditions. His hope is that this 
 effort will be the means of inducing other technical writers to elaborate 
 upon the subject and thus place at the disposal of all students of engineer- 
 ing and all practicing engineers a vast fund of information upon the main 
 general underlying principle which should nearly always govern in the 
 conception, designing, and construction of all important engineering 
 work ECONOMICS. 
 
 It may be of interest to state that for the last eighteen months the 
 speaker has been acting as Chairman of the Committee on "The Study 
 of Economics in Technical Schools" in the Society for the Promotion of 
 Engineering Education; and that he and his co-laborers have been study- 
 ing the question carefully, to the end that they may be able, at the next 
 annual meeting of the society, to present a report thereon which will be 
 of real value, and which, it is hoped, will be the means of establishing the 
 study of economics in all the first-class technical schools of this country 
 upon a sound, logical basis. 
 
 It is the earnest wish of the speaker that the work of that committee, 
 combined with the effect of these three lectures, will result in the publi- 
 cation of an exhaustive standard treatise on "The Economics of Engi- 
 neering", prepared by the labor of a large group of prominent American 
 engineers, selected from all lines of technical activity. 
 
 56 
 
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