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 London Underground The London Underground (also known simply as the Underground, or by its nickname the Tube) is a public rapid transit system serving the capital city London and some parts of the adjacent counties of Buckinghamshire, Essex and Hertfordshire in the United Kingdom. The Underground has its origins in the Metropolitan Railway, the world's first underground railway. Opened in 1863, it is now part of the Circle, Hammersmith & City and Metropolitan lines; the first line to operate underground electric traction trains, the City & South London Railway in 1890, is now part of the Northern line. The network