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 2010 it formed part of the Upminster constituency. Upminster is within the Havering and Redbridge London Assembly constituency and the London European Parliament constituency. Upminster rises to about above sea level to the north and is about above sea level to the south. It rests on a layer of loam, above sand and gravel in the south and London Clay to the north. It is bounded in the west by the River Ingrebourne and there is a stream running east-west, just north of Corbets Tey that has been dammed to form a lake. It has formed part of the continuously