CLASSIFICATION OF CARS.
379. Railroad cars come under three general heads,
Those for passenger transport,
Those for freight traffic,
Those for repairs of the road.
380. The American passenger car consists of a body about fifty feet long, ten feet wide, and seven feet high, containing seats for about sixty passengers, being cushioned, warmed, lighted, and ventilated. Except for emigrants, second and third class cars are but little used in America.
House, box, or covered freight cars, differ from the “flat,” or platform car, only in having a simple rectangular house, about six feet high and nine feet wide, built upon the floor. This is used for the protection of such freight as will not bear exposure; as furniture, books, dry goods, hardware, and small machinery. Carriages, boxes, bales, masts, lumber, and fuel are carried by platform cars. Bulky machinery, and first and second class freight too large for the box cars, should be protected by tarpaulins.
381. The general arrangement of wheels, springs, and brakes, is the same for the several classes of cars, the chief difference being in the ease of springs. Each car rests upon two “trucks,” consisting of four, six, or eight wheels, so connected by levers and springs, as best to absorb shocks, and connected with the body by a pin only, by which the passage of curves is made quite easy.
Cars used for the movement of earth are so arranged as to allow the body to be tipped up, that the contents may be quickly “dumped,” either at the sides, ends, or middle, as desired.
382. Upon some roads, a continuous draw bar is passed under the whole train, the several cars being attached to it, and to each other by safety chains only. By adopting this, and at the same time by springing the buffer beams tight upon each other, the whole train becomes one piece; and the jerks at stopping and at starting are in a great measure avoided.