Page images
PDF
EPUB

Ohio, which uses steam engines (not turbines) and distributes the power fifty-nine miles. These are all practical plants in continuous operation. The plant in California has transmitted power for use during an emergency over a distance of two hundred and seventy miles. Naturally the generators of the majority of these long distance currents have falling water as a source of power. If coal were used it would be transported. We have, however, a different problem to face in the anthracite fields, namely, an excellent steam fuel necessarily produced in order to make the domestic sizes, which steam fuel must come into direct competition with low-priced bituminous coal. Some of the possibilities of electric power transmission in a region of cheap fuel are being demonstrated by the Lackawanna and Wyoming Valley Electric Railroad between Scranton and Wilkes-Barre. It has had remarkable success, and has recently established electric circuits for the supply of cheap power to industrial plants located along its route, and is thus adding to the revenue derived from its ever increasing volume of freight and passenger traffic. The engineers of the Delaware and Hudson Company are investigating the possibility of operating their Pennsylvania properties by electricity. These properties consist of about thirty different operations, including both breakers and washeries and thirtyseven miles of railway from Carbondale to Wilkes-Barre. Up to the present time it has not been deemed advisable to make the change owing to the density of traffic and numerous switches to mining operations; but the engineers are now reaching the conclusion that it would be practicable to make the substitution. It is believed that electrical operation will greatly reduce cost, especially in view of the many detached plants the expense of which has greatly increased since firemen and engineers had their working day reduced to eight hours. The best argument for or against the use of electricity as a power to be distributed from a central plant to take the place of many small plants is whether or not large companies are making the change. Here in New York we have seen the complete change from steam locomotives to the electric system on the elevated service of the Brooklyn. Rapid Transit, and the Manhattan Elevated of the Interborough System. We have witnessed the change from underground cable to electricity on the Metropolitan at an enormous expense. The New York Central and New Haven and Hartford roads are

making tremendous changes, substituting electric equipment for steam locomotives; and the electric zone of the Pennsylvania will cover a very extensive territory. The Lackawanna and Erie Railroads could make advantageous alterations with benefit to their heavy suburban traffic. Such changes as these are not carried out because of the whim of some officer, or because a board of directors are influenced by their holdings of stocks in electric equipment companies, but by the fact that the electric equipment is more efficient than steam.

As to long distance transmission, there is very little loss of power. It is estimated by eminent electricians that the current can be conveyed one hundred miles with a loss of only 5 per cent.; and, for a distance of two hundred miles, with a loss of not over 9 per cent. A slight additional loss, not over 10 per cent., would be experienced in transforming a current of high potential to one of a lower, for use.

The relative value of steam and electricity can best be studied by means of a concrete comparison of the two powers, such as was given in a paper "On the Substitution of the Electric Motor for the Steam Locomotive," by Messrs. Lewis B. Stillwell and Henry St. Clair Putnam, presented at the two hundred and thirteenth meeting of the American Institute of Electrical Engineers at New York, January 25th, 1907, and which will be found in full in the proceedings of that body, Volume XXVI, No. 1. The discussion immediately following is an abstract of the features presented in this paper. The standard used is based on the grand average results obtained in operation by steam locomotives upon the existing railways of the United States, as set forth in the reports of Statistics of Railways for 1904 compiled by the Interstate Commerce Commission; and proof-sheets of the report of the Commission for the year 1905. In estimating operating expenses of electric equipment, conclusions are based upon results obtained in practice so far as the necessary data are available. Where the distance exceeds thirty miles, higher potentials than eleven thousand volts are necessary; and transformers must be installed in the power house for increasing the generated potential, and transformers located at suitable intervals of from thirty to fifty miles, depending chiefly upon the density of traffic, to lower the potential for use. The estimates which follow are based upon the assumption that single-phase alternating-current equipment is

used; that the trolley potential is eleven thousand volts; that each power-house supplies railway line with power to a distance of one hundred and fifty miles in each direction, the feeder potential employed being sixty thousand volts; that the overhead construction is first class in every respect; and steel bridges and field poles set in concrete being exclusively used for the support of both trolley conductors and feeders.

TABLE SHOWING PER CENT. OF COST OF OPERATING
UNDER STEAM AND ELECTRIC SERVICE.

[blocks in formation]

TABLE SHOWING PER CENT. OF COST OF OPERATING UNDER STEAM AND ELECTRIC SERVICE-Continued.

[blocks in formation]

By referring to the recapitulation of the operating expenses under the two systems, we note a saving of 17.823 per cent. by the use of electricity, which saving is found to be entirely in maintaining the equipment and conducting the transportation. By referring to the detail of each grand division, it will be seen that these items have been studied out with great care. The

authors have thoroughly discussed each item, and the interested reader is respectfully referred to the paper quoted, for additional information.

The item "Fuel for Locomotives" (No. 22) is of special interest to us and I will quote as follows:

"One of the marked economies resulting from the substitution of the electric motor for the steam locomotive in railway operation is in the reduction of the fuel account. The cost of fuel upon the average steam railway in the United States for the five years 1901 to 1905 inclusive constituted 11.292 per cent. of total operating expenses. The aggregate cost in 1905 was $156,429,245.

“The following figures show comparative fuel consumption upon the Manhattan Railway during the year ending June 30, 1901, when steam locomotives were employed, and during the year ending June 30, 1904, when electricity was used. During the period first mentioned one pound of coal produced 2.23 tonmiles, if the weight of the locomotive be included; and 1.5 tonmiles if the weight of the cars only be considered. During the latter period (electric traction) one pound of coal burned at the power house produced 3.85 ton-miles excluding weight of locomotives; therefore the ratio of ton-mileage per pound of coal in favor of the electric operation was 2.57 to 1. Including weight of locomotive it was 1.72 to I.

"The average speed under electric operation was approximately two miles an hour greater than that attained by steam; and, if correction be made for this difference, the ratio of tonmileage per pound of coal, excluding weight of locomotives, is approximately 3 to 1; and, including locomotives, 2 to 1 in favor of electric traction. It should be noted also that in this case the coal burned at the power house was of lower grade, and therefore less expensive than that used by the locomotives; and it is reasonable to expect that in general electric traction will mean utilization of cheaper fuel.

"The works-cost of a kilowatt-hour at the bus-bars of the Manhattan plant is less than 0.6 cent when coal cost $3.00 per ton, this coal having a calorific value of 14,000 B. T. U. per pound. This cost includes fuel, water, labor, maintenance, miscellaneous supplies and, in short, everything except capital charges. Where fuel is less expensive, as in the Middle West,

« ՆախորդըՇարունակել »