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
Upminster built-up area of London since the 1930s and is contiguous with Cranham to the east and Hornchurch to the west. To the north and south there is open land that forms part of the Metropolitan Green Belt and there are open spaces formed by Upminster Golf Club and Upminster Hall Playing Field to the north, Upminster Park and Clock House Gardens to the south, and the Ingrebourne Valley linear park to the south west. The town is effectively divided into north and south parts by the railway line. The north is predominantly residential, with the southern part containing the main