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 1973 Stock London Underground 1973 Stock The London Underground 1973 Stock is a type of rolling stock used on the Piccadilly line of the London Underground. It was introduced into service in 1975 with the extension of the line to Hatton Cross, followed by a further extension to Heathrow Central in 1977. The trains were built by Metro-Cammell between 1974 and 1977, and were refurbished by Bombardier Transportation between 1996 and 2001. They are some of the oldest trains running on the Underground, second only to the 1972 Stock running on the Bakerloo line. In the early 1970s London Transport placed an