ROLLING STOCK Railway rolling stock comprises passenger carriages and goods or freight trucks, or wagons, both carriages and freight wagons being usually termed cars in Canada and the United States.
Passenger Carriages.—The earliest passenger carriages on the Stockton and Darlington and the Liverpool and Manchester railways were practically road coaches mounted on railway axles and wheels, and in the case of the former line were hauled by horses for some time after the line was opened. They were individually named, as were the road coaches of that date, as "Experiment," "Highflyer," and so forth, and the term passenger "coach" applied to railway passenger carriages still survives. The early carriages of about 1840 were i5ft. in length and weighed about 3 tons, with a width of about 7ft.; they were mounted on four wheels, and the majority of early railways catered for three classes of passengers. The first, who paid about 3d. per m., were carried in covered carriages corresponding to the interior of the road coach ; the and class passengers were usually provided with a roof, but the sides of the carriages were left open; whilst the 3rd class were carried in open wagons and provided with little or no seating accommodation. It was the normal practice to construct three "compartments" in each carriage, a first class in the centre and a second class at either end. Third class passengers were not conveyed by the more important trains.
Among the earliest improvements in construction was the in troduction of spring buffers and screw couplings between the carriages, which tended to prevent jolts when the train was starting or stopping. About 1840 third class carriages began to have roofs, and by the Regulation of Railways Act 1844, the rail ways were ordered to provide sides to third class carriages, no mention being made of windows or lights. The same act com pelled the railways to run one train per day at a minimum speed of 12 m.p.h., calling at every station and conveying passengers at a fare not greater than id. per mile. These trains became known as "Parliamentary" trains, and were the subject of much derision in the press of that period. Carriages which were nearly always constructed of wood gradually increased in length and were mounted on six in place of four wheels, while the width was grad ually extended to 9ft. Further remnants of the old road coaching
days lasted in the form of different coloured upper panels, while some lines painted the compartments different colours on the same carriage, a practice still employed by the Paris-Lyon-Mediterranee Railway of France, though for reasons of economy the majority of railways now paint their carriages a standard colour, through out, a notable exception being the G.W.R. with its cream upper and chocolate lower panels.
By 1874 the carriages had increased so much in length that it became necessary to mount them on four axles, arranged in two pairs at either end of the carriage. Each pair was so designed as to swivel independently of the other pair, thus permitting a much easier passage of the curves owing to the carriage body remaining rigid while the bogie under-carriage turned in conformity with the rails on the curve. This system, in a very much improved form, is standard for nearly all railway passenger carriage con struction throughout the world, by far the majority of new passen ger rolling stock being built as 8-wheeled bogie carriages. Six wheeled carriages continued to be built in Great Britain for sub urban services until the end of the 19th century, but there have been very few 4 or 6-wheeled passenger carrying vehicles built for British railways since then, although on some Continental railways they remain the standard type for local trains. In France there exist some very long passenger coaches of about 6oft. mounted on two axles only, but such a design does not add to the comfort of the passenger on lines with sharp curves. In Canada and the United States all passenger cars have been mounted on two bogies with four or six wheels each from almost the com mencement of the railway era. This policy was due to the less expensive permanent way provided in newly developed countries and the more usual presence of sharp curves. The addition of an extra axle to each bogie became necessary in North America on account of the great increase of weight consequent upon the adoption of steel carriage construction in the 20th century. On British and Continental railways the added weight caused by the two extra axles is not regarded as being balanced by the advantage of smoother running except in the case of dining or sleeping cars.