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
London fare zones W. On maps these stations are shown as being outside fare zones 1–9 but within the 'special fares' Oyster pay as you go area. In January 2016, the Oyster and contactless system was extended to Gatwick Airport in Crawley, West Sussex, and the stations down that line (Horley, Salfords, Earlswood, Redhill and Merstham). London fare zones Rail service fares in Greater London and the surrounding area are calculated in accordance with the London fare zones system managed by Transport for London. Within London, all London Underground, National Rail, London Overground, TfL Rail and Docklands Light Railway stations are assigned to