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
West Croydon to Wimbledon Line West Croydon to Wimbledon Line The West Croydon to Wimbledon Line was a railway line in south London. It was built by the Wimbledon and Croydon Railway (W&CR) over part of the trackbed of the Surrey Iron Railway. It opened on 22 October 1855 connecting the South West Main Line of the London and South Western Railway (LSWR) to the London Brighton and South Coast Railway (LB&SCR). National Rail services ceased and the line eventually shut down in 1997 for it to be changed over into a new route for the Tramlink network which eventually rolled into passenger service in