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.
Learn more about rapid transit with a free trial on Britannica.com.