Rapid Transit

A high-capacity electric rail mode, commonly called a metro or subway, that runs on an exclusive right of way separated from street traffic by tunnels, elevated structures or fenced surface track, using multiple-unit trains that stop at fixed stations along the line. London's Metropolitan Railway opened the first such system in 1863, running steam locomotives partly underground before electrification followed decades later. Because it carries large numbers of passengers at high frequency over relatively short distances within a city, rapid transit forms the backbone of many major metropolitan transport networks. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/