PHILIP TORCHIO (New York Edison Company).—The growth of large electrical undertakings has been the evolution from small beginnings. In the case of railroad electrification, however, the problem has been quite different. With an established heavy traffic which does not allow of interruption or delays, a new system of traction is to be substituted, requiring radical structural changes all along the line and an entire new system of power generation and distribution.

The engineers confronted with the problem have attacked it in a comprehensive and thorough manner, developing complete systems as self-sustaining and autonomous as the progress of the art allowed them to accomplish at the time. Mr. Murray has described the operation of a system which really went a step further and anticipated the progress of the art by many years. The importance of this epoch-making “experiment" is naturally immensely valuable.

The author emphasizes the point that the experience of the New Haven will benefit the other railroads in solving their problems of electrification. In this connection I wish to call attention to the item of investments in power-houses and power-transmitting lines, which in all the original electrifications were assumed as a necessary part of the equipment, but which in late years the railroads have found more economical to omit from their investment, substituting purchased power delivered to them by central-station power companies. The New Haven has purchased from The New York Edison Company all the power required for its western section of the alternating-current lines and terminals. The Pennsylvania Railroad has purchased from the Philadelphia Electric Company the power for the electrification of its main line from Philadelphia to Paoli and for its other contemplated extensions around Philadelphia. The London, Brighton and South Coast Railway Company buys current from the London Electric Supply Corporation, Ltd. The Chicago, Milwaukee and St. Paul Railway and the Butte, Anaconda and Pacific Railway buy power from the Montana Power Company.

Along every large railroad where the heavy traffic would warrant electrification there is, or can be made readily available, abundant supply of electrical power from power companies. These companies, by averaging the power demand from a great diversity of users, reap economical advantages in investment and

in generation and distribution of power which the railroad cannot secure under independent generation. I wish to call attention to this phase of the problem, as the saving in investment in stations, substations and transmission lines may represent a sensible item in the investment of railroad electrification.

The central stations, besides offering investment and operating advantages, can furnish, in addition, a more reliable supply of power, because they command the best knowledge of the art of electricity supply, which is their exclusive and specialized business.

W. A. DEL MAR (New York City).—This paper is interesting not only as a statement of operating results with the singlephase system of traction but also as a basis of comparison between steam and electric traction. Indeed, so nearly equal are the principal electric systems from an economic point of view that we may well afford to neglect their rivalry in view of the more vital rivalry between steam and electricity. I believe that the "battle of the systems" was largely caused by the advocates of each system being so carried away by enthusiasm as to be unable to tell the whole truth, whether in defending their own or criticising the others. Here, at last, we have a presentation of operating results, making it unnecessary to base conclusions upon specious arguments about details.

It is unfortunate that the operating costs are given for only two months of the year. The results would have been more valuable if they had been based upon a complete year, as it is almost impossible to select two really representative months, especially in view of inevitable variations of maintenance costs of equipment. The omission of the annual fixed charges is also to be regretted, as it is well known that the running charges can be made less with electric than with steam traction, but it is not always clear whether the fixed charges added by the electrical plant will destroy the favorable balance due to operating economies. Various cost data are presented, but in such form as not to be available for calculating fixed charges. We do not know, for example, whether the $15,000,000 expenditure mentioned by Mr. Murray includes the cost of reducing telephone disturbances and of altering the right-of-way to conform with electrical requirements.

One cannot help being appalled at development charges

amounting to forty per cent. of the entire investment, as one would infer from Mr. Murray's statement that the present system could be replaced for sixty per cent. of the original investment. An interesting feature about the installation has been the development from the complex to the simple in mechanical details, and vice versa in the electrical features.

Examining the operating costs with the view of comparing them with steam operating results, one is confronted by a series of questions which, if unanswered, will render such comparison difficult. Having gone to great trouble to segregate and clearly present the operating costs, Mr. Murray proceeds to obtain unit. costs by dividing these operating costs by car mileages and train mileages of unspecified nature. It is to be hoped that Mr. Murray will state the nature of the mileages with greater detail, particularly as to whether they include yard switching and light locomotives. These two items may easily amount to fifteen per cent. of the entire milieage.

The fixed charges given for the Cos Cob power station appear to be very low. It would be interesting to know whether they include depreciation.

An interesting feature of the New Haven installation is the use of meters on the locomotives. This enables an intelligent estimate to be made of the relative cost of different classes of service, such as passenger locomotive, freight, and multiple-unit. Meters on locomotives are not very accurate, due to vibration, but it is interesting to note that, provided the vibration is impartial with respect to making the meters read high or low, the probable error in the aggregate reading will be quite small, due to the large number of locomotives. Thus where there are 100 locomotives a possible error of twenty per cent. in each meter will cause a probable error of only = 2 per cent. in the total.

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Electric railway men should feel very grateful to Mr. Murray for this paper, which will long be consulted as a classic upon a great engineering topic.

MR. R. H. WHEELER (Assistant Electrical Engineer, Mackenzie, Mann & Co., Ltd., Montreal, Canada).—In this paper there comes a boon to those interested in the application of electricity to train movements in the practical definitions of condiVOL. CLXXX, No. 1075-7

tions which affect the success of a railroad electrification, supplemented by copious data resulting from an extended period of operation. The haze from the "shots" of the "battle of systems" now clears away from the single-phase side of the field, showing an interesting array of results achieved.

Two points, from the many ably put forth, appeal to me for special emphasis. These are vital to the success and quantity of success, which latter is the chief "lure" of electrification.

First. The careful analysis and choice of a form of electric power which may be standardized for all classes of train service on that road.

Second. The "inheritance" to electric operation of "steamtrained" operators.

Under electric operation the power plant is separated from the locomotive, and it is evident that the economy of energy transmission, from its source to the wheels of the engine, is paramount. The overhead contact wire lends itself very readily to this transmission duty, in yards, terminals, on the road, and elsewhere. For reasons of high economy of transmission and diversity of transformations, Mr. Murray suggests that this wire be energized with 11,000 volts single-phase, 25-cycle power. By the use of the mercury-arc rectifier the admirable qualities of the series. direct-current motor can be retained. This motor is especially desirable where the "density of traffic" factor is highest, as in suburban and terminal electrification, on account of its accelerating capabilities and weight economies, both in itself and its control. However, to carry about a rectifier upon the class of equipment employed in terminal service, even if rectified single-phase current were suitable, would impose a serious handicap in both weight and control complication. Rectified single-phase current is not ideal for direct-current motors of the usual design, requiring increased thermal capacity and thus weight. These reasons militate against the "standard" proposed as suitable for all classes of train service.

However, by placing the rectifier in the roadside substations and taking advantage of the economies and freedom of disturbance to other local circuits of a balanced three-phase, sixtycycle supply, another "standard" results which supplies, over the overhead contact wire, power at 3000 volts direct current, and

which has the desired essentials of transmission economy and standardization of motive power equipment. In the case of heavy grade divisions operated by rectifier substations, engines arranged for regeneration would be employed. This second "standard" is offered to emphasize Mr. Murray's definition of the successes arising from a choice of energy which can be standardized. A railroad which, in its initial electrification, utilizes a system which is capable of being extended through successive increases of electrically-operated territory has gone far to ensure successful electrification.

With the figures Mr. Murray presents, indicative of the successful operation of the New Haven motor cars and A. C.-D. C. engines since the last overhaul in a well-appointed maintenance shop, it is evident that the straight alternating-current engines will show greater economies. When the data are available from the Butte, Anaconda and Pacific Railroad, Chicago, Milwaukee and St. Paul Railroad, and Canadian Northern Railway giving results of operation, especially as the latter is to employ 2400-volt motor cars, another decisive step towards standardization can be made.

Secondly, I wish to emphasize the importance that "heredity" plays. Mr. Murray states that a thorough understanding must be had of the fundamental differences of steam and electric operation. Electric operation is a more exact science than steam operation, since a great many of the variable factors are removed. Chief of these, the power generating plant, is removed from the hands of the fireman, and he cannot now produce more power to get an overloaded engine over the road. Certain rules and axioms the officials of the operating department must appreciate in their adapting themselves to the era of electrification.

As well, the proper care and thorough inspection of electric equipment should be insisted upon and the long life resulting from renewals and not repairs be gained. It takes thorough investigation and time to care for such equipment, and in the early stages a little more lee-way should be given the shopmen. Coöperation in these things will produce the economies which make an electrification successful.