Subway is an underground railway that usually serves as part of a rapid transit system in an urban area. Although parts of such a railway system may be at ground level or elevated, the system as a whole is generally referred to as a “subway” if any part of it is underground. Subways are most useful in crowded urban areas, where heavy traffic often slows travel by bus or car. Subway passenger capacities in such cities as Chicago, New York City, and Washington, D.C., can be up to 10 times higher than those of other modes of transportation.
Loading the player...Passengers boarding a subway train
There are three types of subway tunnel construction. Cut and cover construction involves digging up streets, building the tunnel, and then covering it. In cover and cut construction, a crew lays a concrete slab cover and then digs the tunnel underneath it. In a third method of construction, the tunnel is drilled and lined at the same time using a special tunnel-boring device commonly known as a tunneler. The tunneler uses a cutting head to drill the tunnel and then immediately assembles the lining behind the head using precast concrete or steel pieces.
London’s subway system, the longest in the world, provides quick, cheap transportation to all parts of the city and suburbs. It handles more passengers than any other system in the world. London’s system is often called the tube or the underground. Some of its lines are so far underground that passengers take elevators down to board trains. New York City’s subway system is the longest in the United States.
Many of the world’s other major cities also have extensive subway systems, including Baltimore; Beijing; Buenos Aires, Argentina; Cairo, Egypt; Chicago; Edmonton, Canada; Istanbul, Turkey; Kolkata, India; Los Angeles; Mexico City; Montreal; Moscow; Paris; Philadelphia; San Francisco; São Paulo, Brazil; Seoul, South Korea; Shanghai; Tokyo; Toronto; and Washington, D.C.
London was the first city to have a subway. Its first underground passenger line opened in 1863. It used steam locomotives. The first deep-level line opened in London in 1890 and had electric locomotives. All subways since then have used electric power. Boston was the first U.S. city to have a subway. It opened a line of 11/2 miles (2.4 kilometers) in 1897. The first sections of New York City’s subway opened in 1904.
See also Electric railroad ; New York City (Transportation) ; Transit ; Tunnel .
