The District line is a London Underground service that crosses Greater London from east to west. From Upminster, the eastern terminus, the line runs through Central London to Earl's Court before dividing into three western branches, to Ealing Broadway, Wimbledon and Richmond. There is a short branch that goes from Earl's Court to Kensington (Olympia). A branch also runs north from Earl's Court to Edgware Road via Paddington. Coloured green on the tube map, the line serves 60 stations in 40 miles (64 km), and with bridges across the Thames on the Wimbledon and Richmond branches is the only London Underground line to cross the river in this way. The track and stations between Barking and Aldgate East are shared with the Hammersmith & City line, and between Tower Hill and Gloucester Road and on the Edgware Road branch with the Circle line. Some of the stations are shared with the Piccadilly line. Of the 60 stations served, 25 are below ground. Unlike London's deep-level tube railways, the railway tunnels are just below the surface, and the trains are of a similar size to those on British main lines.