Text 2. SUBWAY

Subway, also called underground, tube, or metro, underground railway system used to transport large numbers of passengers within urban and suburban areas. Subways are usually built under city streets for ease of construction, but they may take shortcuts and sometimes must pass under rivers. Outlying sections of the system usually emerge above-ground, becoming conventional railways or elevated transit lines. Subway trains are usually made up of a number of cars operated on the multiple-unit system.

There are three types of subways. One is called the open cut. The construction crew tears out the streets and builds the subways in deep ditches. If two lines are going to cross, the crew digs one roadbed deeper than the other. If the crew lays a pavement or other type of cover over the cut in the ground, the subway is called a cut and cover subway. The third form of subway, which is called a tube, is constructed by boring through the earth at the desired depth without disturbing the surface. This type of construction is for one or two tracks. The tunnels of an open-cut subway have a rectangular shape. The tunnels of a tube subway are usually circular or semicircular. New York City's subway is mainly rectangular. Much of the London subway is semicircular.

London's underground. The first subway system was proposed for London by Charles Pearson, a city solicitor, as part of a city-improvement plan shortly after the opening of the Thames Tunnel in 1843.

After 10 years of discussion, Parliament authorized the construction of 3.75 miles (6km) of underground railway between Farringdon Street and Bishop's Road, Paddington. Work on the Metropolitan Railway began in 1860 by cut-and-cover methods—that is, by making trenches along the streets, giving them brick sides, providing girders or a brick arch for the roof, and then restoring the roadway on top. On Jan. 10, 1863, the line was opened using steam locomotives that burned coke and, later, coal; despite sulfurous fumes, the line was a success from its opening, carrying 9,500,000 passengers in the first year of its existence. In 1866 the City of London and Southwark Subway Company (later the City and South London Railway) began work on their "tube" line, using a tunneling shield developed by J.I I. Greathead. The tunnels were driven at a depth sufficient to avoid interference with building foundations or public-utility works, and there was no disruption of street traffic. The original plan called for cable operation, but electric traction was substituted before the line was opened. Operation began on this first electric underground railway in 1890 with a uniform fare of two pence for any journey on the 3-mile (5-kilometre) line. In 1900 Charles Tyson Yerkes, an American railway magnate, arrived in London, and he was subsequently responsible for the construction of more tube railways arid for the electrification of the cut-and-cover lines. During World Wars I and II the tube stations performed the unplanned function of air-raid shelters. Today, London has 10 lines that provide quick, cheap transportation to all parts of the city and suburbs. This subway system is often called the tube or the underground. Some of its subway lines are so far underground that passengers go down on elevators. There are numerous escalators which help to keep the traffic moving. The first was installed in 1911. One of them at Leicester Square is over 80 feet in length. On long escalators the speed is changeable. The "up" escalator runs at full speed when carrying passengers, but when empty it runs at half speed. Many of the new escalators have automatic control making a more frequent service throughout the day possible.

Automatic trains, designed, built, and operated using aerospace and computer technology, have been developed in a few metropolitan areas, including a section of the London subway system, the Victoria Line (completed 1971). The first rapid-transit system to be designed for completely automatic operation is BART (Bay Area Rapid Transit). Air-conditioned trains with lightweight aluminum cars, smoother and faster rides due to refinements in track construction and car-support systems, and attention to the architectural appearance of and passenger safety in underground stations are other features of modern subway construction.

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