In the development of transportation service, the demand for faster freight train speed has, on many roads, become so pressing, that the economic benefit of a larger train load, which the locomotives of greater power should accomplish, has not been fully realized, the greater power of modern engines being consumed against the resistance of faster speed, instead of hauling greater loads. In this connection, the following table, showing resistance of railway trains at various speeds, is of interest.

It will be noted that if the full power of a given locomotive is exerted to move a train of specified weight, on a level grade, 15 miles an hour, a locomotive of twice the hauling capacity (capable of moving twice the load at the same speed) could only move the same load at a speed of a little over 30 miles an hour. The effect of mountain grades on the power required to move trains is also indicated by the table, which shows the power required to move a given load up a 4% grade, at 10 miles per hour, is over seventeen times greater than on a level, and at 25 miles an hour, over ten times greater than the resistance to be overcome on a level track.

RESISTANCE OF RAILWAY TRAINS-LOADED CARS.*-IN POUNDS PER TON (2000 POUNDS).

In the design and construction of cars, the weights and carrying capacity have kept pace with locomotive development. Modern standard 12-wheel Pullman Sleepers weigh about 90,000 pounds; first-class passenger coach, for sixty passengers, 57,000 pounds, and the ordinary standard freight car of 1892 has a carrying capacity of 60,000 pounds, and weighs (box pattern) from 28,000 to 32,000 pounds; cars of 120,000 pounds carrying capacity are not uncommon.

"A notable special car was recently required for carrying a 12-inch gun

*Resistance of empty cars about two pounds per ton greater than loaded cars at low speeds. About six pounds per ton greater at fifty miles per hour. NOTE. This table is based on experiments made in 1878 on the Lake Shore and Michigan Southern Railway by A. M. Wellington, C. E. For low speeds the figures are somewhat less, and for high speeds, somewhat greater, than by formula for English rolling stock, by D. K. Clark.

stripped for shipment, weighed 100,800 pounds. The Pennsylvania Railroad supplied the car, which is shown herewith, as loaded. The side sills of the car are plate girders, 39 feet long over all, and similar to those used in special cars for transporting wire cables. Equalizing levers distribute the load on each end to two 4-wheel trucks of ordinary diamond pattern. The plate girders are 7 feet 9 inches apart, out to out. Their depth at the center is 23 inches, and at this point the clear height above the rail is 2 feet 7 inches. The wheel base of each set of double trucks is 13 feet 3 inches, each truck having a 5-foot wheel base, and the axle centers of the adjacent wheels of the two trucks being 3 feet 3 inches apart. The total wheel base of the car

is 35 feet. The wheels are 33 inches diameter. The total weight of the car is 54,800 pounds. The gun was supported and secured by blocks bolted to the car floor." *

While the improvement in cars, both in kind and capacity, has kept pace with the demands of traffic, it may not be inappropriate in this connection to append a list of the different varieties now in use. It is probable that this list is incomplete, but will serve the purpose of giving an idea of the kind of cars brought into requisition by the demands of commerce.

The cost of locomotive service in different

indicated by the table hereunder, the disadvantage of the United States is

of extreme western roads,

in respect to the cost of fuel, being particularly noticeable.

LOCOMOTIVE RETURNS FOR THE MONTH OF JANUARY, 1892.*

Compound locomotives have, in recent years, been coming into favor, as compared with the ordinary simple or single expansion type. In the compound engine, steam is admitted from the boiler to a high pressure cylinder; after driving the piston through a half or single stroke, it is exhausted into a cylinder of larger diameter, and after driving the piston therein a half stroke, is discharged into the atmosphere. Several kinds of compound engines are performing service in this country, the leading types, so far, *From the "Railroad and Engineering Journal."

cylinders (a high and a low pressure cylinder on each side of the locomotive), the piston and main rod being connected by a cross-head of ingenious design. Another type, illustrated by Plate 23, is the two cylinder compound, built by the Schenectady Locomotive Works.

The equipment of all railroads in the United States, reporting to the Interstate Commerce Commission, is summarized by the statistician of the Commission for June 30, 1890, as follows:

From the foregoing it will be seen that, practically all cars in the passenger service are fitted with train brakes and automatic couplers. The attention of railway managers has, in recent years, been earnestly directed to the desirability of using approved and reliable form of automatic coupler for freight cars. The Master Car Builders' Association adopted a form of automatic coupler which is now generally regarded, and is likely to be continued, as the standard form for all United States railways, unless consideration of the subject by Congress should result in an unwise interference, through the