Subway

Subway, underground railroad system designed for urban and suburban passenger transport. The first subway, known as the Underground, was built in London (1860–63) and used steam trains. From 1886 to 1890 a 3-mile section of the London subway was built using a large, cylindrical steel tube (developed by J.H. Greathead) that was forced forward through the earth by hydraulic jacks; tunnel walls were then built around it. This technique made deep tunnels possible without surface disturbance. The London “tube” thus constructed was the first to use electrically-powered trains, which soon replaced steam trains everywhere. Many cities throughout the world then followed London's lead, notably Paris (begun 1898) and New York (begun 1900). The New York subway, using multiple-unit trains developed by Frank Sprague, is now the largest in the world. The Moscow subway (begun 1931) is noted for its palatial marble stations. Many cities have extended, improved, and automated their subway systems to reduce surface congestion. Some, such as Montreal, have introduced quieter rubber-tired trains that run on concrete guideways.

See also: Railroad.