Coloured green on the Tube map, the line serves 60 stations (more than any other Underground line) over . It is the only Underground line to use a bridge to traverse the River Thames, crossing on both the Wimbledon and Richmond branches. The track and stations between and are shared with the Hammersmith & City line, and between and and on the Edgware Road branch they are shared with the Circle line. Some of the stations between and are shared with the Piccadilly line. Unlike London's deep-level lines, the railway tunnels are just below the surface, and the trains are of a similar size to those on British main lines.