London underground railway system (or 'tube', as it is known locally) celebrated its centenary in 1990 and is internationally famous, ranking alongside the Paris metro and the New York subway. London's tube network covers the largest area of any underground rail system, with 242 miles (391km of tracks, of which around 106 miles (171 km) is underground, and 267 stations. The tube runs to all areas of central and greater London, connecting all mainline station