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 A60 and A62 Stock stock. London Underground A60 and A62 Stock The London Underground A60 and A62 Stock was a type of sub-surface rolling stock which operated on the Metropolitan line of the London Underground from 12 June 1961 to 26 September 2012, and on the East London Line from 1977 until 22 December 2007, when it closed to be converted into London Overground (except in 1986, when one person operation conversion of the fleet took place). The stock was built in two batches (A60 and A62) by Cravens of Sheffield in the early 1960s, and replaced all other trains on the line. At