rapid transit

London UndergroundA train departing from a London Underground subway station. London's subway is often called “the Tube” because of the shape of the tunnels.

rapid transit, system of railways, usually electric, that is used for local transit in a metropolitan area. A rapid transit line may run underground (subway), above street level (elevated transit line), or at street level. Rapid transit is distinguished from other forms of mass transit by its operation on exclusive right-of-way, with no access for other vehicles or for pedestrians. See elevated transit line; mass transit; subway.

This article was most recently revised and updated by Chelsey Parrott-Sheffer.