London Underground at +420 V, giving a potential difference of 630 V. On the sections of line shared with mainline trains, such as the District line from East Putney to Wimbledon and Gunnersbury to Richmond, and the Bakerloo line north of Queen's Park, the centre rail is bonded to the running rails. The average speed on the Underground is 20.5 mph. Outside the tunnels of central London, many lines' trains tend to travel at over 40 mph in the suburban and countryside areas. The Metropolitan line can reach speeds of 62 mph. The London Underground was used by 1.379 billion passengers in
Art on the Underground Kensington's museum subway, and at Charing Cross and Earl's Court tube stations among others. Many other stations on London Underground host temporary exhibitions, with past locations having included Canary Wharf, Piccadilly Circus, Charing Cross, Southwark and Westminster stations. Art on the Underground Art on the Underground, previously called "Platform for Art", is a visual arts showcase sponsored by London Underground, the rapid transit system for London, England. London Underground's associations with visual art began in 1908 when its then Publicity Officer Frank Pick began commissioning leading artists to work on poster campaigns for the rapidly expanding network. The company's distinctive