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
Romford–Upminster line saw an end to years of speculation about its future. There is only one intermediate station, at Emerson Park. At the connection west of the station to the main line was severed in 1968. The branch has just one signal, on approach to Romford. There were plans to link the line from platform six at Upminster to the reception tracks of the London Underground depot there. This would have allowed the transfer of London Underground D78 Stock units onto the main line to be hauled away by diesel locomotive for refurbishment at the Ilford depot. These plans were scrapped when