form a valuable addition to the previous contributions which he has made.

As might be expected from experience with any original enterprise, Mr. Murray estimates that the electrical plant of the New Haven road, with the ten years' experience in construction and operation, now available, could be reproduced to-day for not more than 60 per cent. of its original cost. It should be gratifying to all, however, that he also states the financial return will ultimately be sufficient to justify the actual expenditure to date, so that the courageous pioneer will not be a loser. Some road, he says, had to make the first break into the dark, but, from the data assembled, future results in the application of electricity in heavy trunk line territory can be predicated on assembled facts and not predicted from hypothetical analysis.

In considering the economies over steam operation, by means of which electrification can justify the investment which it requires, Mr. Murray puts the matter very simply by pointing out that these economies are normally of three kinds; i.e., saving in fuel, saving in motive power maintenance and repairs, and saving in train miles.

Broadly speaking, he says the costs of the first two items under electrification will be one-half the cost under steam operation. The saving in train miles, however, depends very largely on local conditions and cannot well be generalized. Success in electrification, therefore, is primarily dependent upon density of traffic. This reduces the matter pretty well to its lowest terms and should help eliminate some of the mystery with which the savings to be effected by electrification have apparently heretofore been surrounded in the minds of many railroad operating officials.

A detail in the paper which deserves particular comment is the fact which is pointed out that an electric locomotive, like an over-willing horse, may work itself to destruction if permitted to do so. While it is perfectly possible to keep the cost of maintenance and repairs at one-half those of steam locomotives, under conditions most favorable to steam operation, Mr. Murray says it is only by the most rigorous and careful inspection and conformity to proper rules of operation that this can be done.

This fact is one of the most difficult to impress upon the minds of steam railroad operators, and it is to be hoped that the figures of 8.6 and 10.6 cents per mile for the maintenance and repairs of

the general average of New Haven locomotives, as compared to the average of 3.96 cents per mile for the ten locomotives which have been properly overhauled, will have some effect in bringing about a more thorough realization of this important matter. Incidentally, this figure for the maintenance and repairs of ten locomotives, making 466,524 miles in the seventh year of their age, is a remarkable commentary on the reliability of such equipment when handled intelligently.

The paradoxical action of heavy freight trains in steadying the power-house load instead of causing an increase in the peaks, as it was feared they would do, is also of interest. The fact that these trains, by dropping the voltage slightly, when drawing heavy accelerating currents, naturally cause other trains moving at high speed in the neighborhood to automatically reduce their power requirements, is readily appreciated when once noted, but is one of the many items brought out by actual experience which are often overlooked in advance calculations. Fortunately, in this case the unforeseen item is one which produces a favorable rather than an unfavorable effect on the operation of the system.

Many other items which Mr. Murray has set forth are also worthy of comment, and the entire paper forms a valuable contribution to the subject. We hope that it may serve as an inspiration to other engineers in active touch with the operation of similar properties to present their experiences with equal freedom for the general benefit of the art.

MR. F. E. WYNNE (Westinghouse Electric and Manufacturing Company, East Pittsburgh).—Mr. Murray's paper is a very valuable contribution to the literature of electric railroading, not only on account of the operating data which it contains, but because of its clear exposition of the broad principles to be considered in deciding whether an electrification will be successful. In the past electrical engineers have been accused (and to some extent rightfully so) of advocating wholesale electrification of steam railroads without regard to the measure of success which might be expected. It is therefore very pleasing to find a representative electrical engineer taking the stand that an electrification is only justified when it is an assured success from the standpoint of all parties concerned.

The figure of $15,000,000 given as the expenditure for elec

trification of the New Haven Railroad to date indicates that the expenditure has been $120,000 per unit of motive power and $30,000 per mile of single track. Complete electrification of the New York-New Haven Division will be accomplished without additional expenditure for trolley construction (which is a very large proportion of the total), and consequently these unit figures will be somewhat changed. The total expenditure per unit of motive power will gradually decrease and that per mile of single track will increase to some extent because of the larger number of electric engines in service without increase in the mileage of the electric zone.

The further statement that the present plant could be reproduced at the present time with better operating results for not more than 60 per cent. of the actual cost to date indicates that for an installation similar to the New Haven the total cost may be made less than $70,000 per unit of motive power, while the cost per mile of single track will be in the neighborhood of $20,000. These figures, as noted by Mr. Murray, represent the cash outlay, and in determining the net cost of electrification they will be reduced by the credits for steam equipment replaced,

etc.

The figures given for mileage show that passenger locomotives average approximately 170 miles each daily, and that only 22 per cent. of the total number of passenger trains have the full run of seventy-three miles. This daily mileage per locomotive is comparable to that secured from electric cars operating in rapid transit and heavy interurban service. It therefore seems reasonable to assume that when all through trains are electrically operated the average daily mileage per locomotive may be materially increased.

Similarly the multiple-unit motor cars show an average of eighty-four miles each daily. This is relatively low, but is undoubtedly due to the fact that local trains are bunched in the morning and evening rush hours to a greater extent than is ordinarily found. This low mileage, together with the fact that over half of the total multiple-unit trains operate with only one trailer per motor car, indicates that the railroad is not yet getting the full benefit of the rather large equipments on the

motor cars.

The figures given in connection with the operation of the

switching engines illustrate the remarkable reliability and operating economy of electric locomotives in this particular class of service. Such results lead us to believe that the field for the electrification of railroad yards is a large one and that considerable progress in this direction will follow a full appreciation of the success which may be expected. As density of traffic is one of the largest factors in determining the advisability of electrifying main lines, so the desirability of yard electrification will largely be determined by the degree of congestion existing. In such installation the initial expense may be reduced to a minimum where central station power is available.

Mr. Murray states that electrification very quickly increased the reliability of operation to some three or four times that of the steam operation it replaced. We do not altogether understand what is the measure of reliability used in making this comparison, but assume he means that the number of failures were from one-third to one-fourth as many as were encountered during steam operation for a similar period.

In connection with Mr. Murray's statement that maintenance and repairs on electric locomotives amount to approximately onehalf those required for steam locomotives with equal weight on drivers, I should like to ask whether operation in equal service also should not be part of the basis of comparison.

The remarks regarding the differences in the natures of electric and steam engines are particularly pertinent, and Mr. Murray's plea for electrically-trained men in the administrative department of electrified steam railroads points out one of the things which is of the highest importance in securing the fullest measure of success in electrifications.

It is interesting to note the results secured in connection with energy consumption, as these closely check the accuracy of calculations made in connection with this service, thus illustrating the fact that the energy consumption with electric operation can be very closely predetermined where trains are operated on a steam railroad basis; that is with definite schedules and definite stops. The figures given show further how rapidly the consumption of energy increases with the increasing number of stops as indicated by the several classes of service. Since the electrical equipment is merely apparatus for converting electrical into mechanical energy, it follows that with increased unit energy consumption

increased work is required of the electrical equipment, and therefore electric locomotives will safely handle much greater tonnages in through service than in local service. They will also handle greater tonnages at moderate speeds than can be operated at high speeds.

The information regarding the improvement of load factor and smoothing out of the curve of power station output with the addition of trains (even though those trains were comparatively heavy) illustrates a principle which has been found to exist in connection with city and interurban electric railways; namely, that the peak load on the system increases less rapidly than in proportion to the increase in number of cars or trains operated. However, in city and interurban systems this is probably due more to the fact that as the number of cars operated increases a smaller proportion of the total are starting simultaneously, rather than to the fly-wheel effect of the moving cars. We are inclined to the opinion that with further increase in the number of trains electrically operated by the New Haven Railroad some benefit in the improvement of load factor and reduction of peaks will be secured from this source, as well as from the fly-wheel effect of the moving trains.

The reduction in cost of the trolley construction which has been made since the initial installation shows great progress in the right direction. However, we believe that it is not yet sufficiently low to represent maximum all-around economy. This belief is strengthened somewhat by Mr. Murray's statement of the extraordinary reliability of the overhead construction in stormy weather. This great degree of reliability leads us to question whether part of the cost of the overhead construction may not be due to its being designed with an unnecessarily great factor of safety.

In connection with Table 17, only interest, taxes, and insurance are specified as fixed charges. I should like to ask whether a depreciation allowance is included in the figures given.

I feel that the Institute is to be congratulated upon securing the presentation of such an able paper, and trust that its author may continue to make public his valuable data regarding the principles of railroad electrification, to the end that electric operation of steam railroads may be extended and may be attended by the greatest success.