STREET-RAILWAY LOCOMOTIVES. Numerous at tempts have been made, in the United States, to employ compressed-air locomotives for propel ling street-railway cars; but. with the exception of a few short lines under special con ditions. these attempts have all resulted in com mercial failures. Probably the most extensive experiments have been conducted in New York City, on some of the railway lines crossing the city from east to west. In all of these experi ments a locomotive ear has been employed carry ing the tanks underneath the seats or muter the floor of the ear. In Europe the Mekarski sys tem of compresIted-air street-ear loeomotion has been used apparently with considerable success in Paris, France, and Berne, Switzerland. A special feature of the Slckarski system is the heating of the air, to maintain it at a con tart temperature, by passing it through superheated water at 330° F. The air thus becomes saturated
with steam, which subsequently partly con denses, its latent heat being absorbed by the expanding air. The pressure used at Berne in the car reservoirs is 440 pounds per square inch. The engine is conFt•ucted like an ordinary steam tramway locomotive, and drives two coupled axles spaced 5.2 feet apart. It has a pair of outside horizontal cylinders, 5.1 by till inches: four coupled wheels. 273/4 inches in diameter. The total weight of the car, including compressed air, is 7% tons. The storage-tanks consist of ten sheet-iron cylinders with an aggregate capa city of 04% feet of compressed air. The cars will run for four miles refilling the reservoirs. On the Paris lines the pressure used is 547 and the cars make trips of seven miles without refilling the reservoirs.