Circle line (London Underground) the stations are shared with one or more of the three other sub-surface lines, namely the District, Hammersmith & City and Metropolitan lines. On the Circle and Hammersmith & City lines combined, over 114 million passenger journeys were recorded in 2011/12. The first section became operational in 1863 when the Metropolitan Railway opened the world's first underground line between Paddington and with wooden carriages and steam locomotives. The same year a select committee report recommended an "inner circle" of lines connecting the London railway termini, and the Metropolitan District Railway (commonly known as the District Railway) was formed to build
London Underground Standard Stock and were later reclassified to become Classes 485 and 486. Apart from those cut up following accidents at Ryde depot, and other early withdrawals, most of these units were withdrawn between 1988 and 1991, when they were replaced by London Underground 1938 Stock. In October 1990, five cars were returned to London Transport, to form a Heritage Train. They worked under their own power between Fratton and Wimbledon, and were displayed at an open day at Morden Depot, celebrating 100 years of the Northern line. Standard Stock is used to describe six experimental cars built by five manufacturers in 1923,