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streetcar,small, self-propelled railroad car, similar to the type used in rapid-transit systems, that operates on tracks running through city streets and is used to carry passengers. Most often cars of this type are powered by electricity supplied through an underground third rail or an overhead wire. A device called a trolley that is connected to the streetcar's electrical system makes rolling or sliding contact with the rail or wire; hence the name trolley car often is applied to such vehicles. Streetcars are sometimes powered by diesel or other internal-combustion engines, generally in suburban or rural areas, where the distances to be covered make the cost of electrification prohibitive. The first streetcars, which were drawn by horses, were introduced in New York City during the 1830s. The first electric streetcar system for urban passenger service in the United States was introduced in Cleveland during the 1880s. The use of streetcars expanded in the United States until World War I. Since then most have been replaced by buses, although many still remain in use, and a new system of streetcars has been built in San Diego.
(also tramway or trolley car), a means of urban ground transportation. A streetcar takes electric power from an overhead wire and moves on rails; it may be a single motor car or a motor car with trailing cars.
Proposals for the use of electric power to move carriages were advanced in the 1830’s and 1840’s; practical realization of the idea became possible in the 1870’s with the construction of the first electric power plants. An electrically powered “rail carriage” proposed in 1876 by the Russian inventor F. A. Pirotskii may be regarded as the prototype of the streetcar. In 1880, Pirotskii built and tested a car with an axle-hung DC traction motor. Work on the development of streetcars was also under way in Germany (the firm of Siemens und Halske) and other countries. In 1881 a streetcar was put into service in Lichterfeld, near Berlin. It had a capacity of 20 passengers, reached a speed of 30 km/hr, and made a run of 2½ km. In the 1880’s streetcar service spread to many European countries and the USA. Regular service began in Russia in the 1890’s—in Kiev in 1892, in Nizhny Novgorod in 1896, and in Moscow in 1899.
A modern streetcar enterprise is a complex system consisting of technical facilities such as the track (seeTRACK SUPERSTRUCTURE), automatic block signaling systems, the traction network, the rolling stock, and maintenance services, including depots, repair shops, and field traffic-control departments. Power is obtained from an electric traction network. Electric current is fed to the overhead, or trolley, system through traction substations, which convert AC to DC at 500–750 volts. The motor cars have current collectors, which slide along the wire of the overhead system when the cars are in motion. The rails serve as the return wire.
Streetcar systems use an overhead catenary suspension, in which the trolley wire is suspended by means of insulators directly from the supports of the overhead system or from transverse supporting wires stretched between the supports at a height of 3.75–5.4 m. Advanced electrical equipment makes it possible to avoid starting resistances and to use electric braking, thus substantially reducing noise. The running gear is equipped with sound-absorbing devices—for example, the trucks have rubber-mounted components.
The use of the streetcar as an off-street form of urban transportation is promising. In the 1970’s in the USSR and abroad there was a trend toward the use of high-speed streetcars moving at 1.5–2 times the speed of the ordinary type. High-speed streetcars are especially efficient on lines linking the central urban areas with outlying suburbs, remote industrial areas, and recreation areas. High-speed streetcars require improved track and the use of tunnels or elevated structures at intersections with other transportation routes within the city. The construction and maintenance of the track and operating facilities of a high-speed streetcar require less capital investment than does a subway, over which the streetcar also enjoys the advantage of more efficient management of passenger traffic.
Streetcar service is being improved by the provision of more comfortable cars and the reduction of noise and power consumption. The suspension of the cars and the control system of the traction motors are being improved. Small-capacity cars are being replaced by cars with six axles, which can increase the carrying capacity to 30,000–40,000 passengers per hour.
REFERENCEKutylovskii, M. P., and A. I. Fedotov. Podvizhnoi sostav tramvaia. Moscow-Leningrad, 1948.
N. A. GRUNENYSHEV