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
London Underground in popular culture London Underground in popular culture The London Underground has long provided inspiration in various areas of popular culture. Filming is now managed all over the system but most commonly takes place at stations like Aldwych (a disused tube station), formerly on the Piccadilly line, or the non-operational Jubilee line complex in Charing Cross. The Waterloo & City line has occasionally been used for filming as it is closed on Sundays. The London Underground Film Office handles over 200 requests a month. Although not "filmed" as such on the Underground, there have been two animated children's television series set on and