Metropolitan line the top green light over a yellow light, and clear two green lights. The Metropolitan line's suburban rail character opposed to other London Underground lines is also shown by the long distances between stops. Eight of the top 10 furthest apart stations on the Underground are on the Metropolitan line. The section between Chalfont & Latimer and Chesham is the longest at , whilst the Finchley Road to Wembley Park section is the second longest, and Rickmansworth to Chorleywood the fourth longest overall. The Metropolitan line is the only London Underground line to operate an express service. Designed for commuters
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