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
Art on the Underground Art on the Underground Art on the Underground, previously called "Platform for Art", is a visual arts showcase sponsored by London Underground, the rapid transit system for London, England. London Underground's associations with visual art began in 1908 when its then Publicity Officer Frank Pick began commissioning leading artists to work on poster campaigns for the rapidly expanding network. The company's distinctive corporate image, including official Underground roundel and iconic tube map designed by Harry Beck are also considered major contributions to visual art, and several of the network's stations have been decorated with artistic tiling or murals depicting local