Central line (London Underground) that the transport benefits of a Park Royal station on the Central line are not sufficiently high to justify the costs of construction. Central line (London Underground) The Central line is a London Underground line that runs through central London, from , Essex, in the north-east to and in the west. Coloured red on the Tube map, the line serves 49 stations over , which makes it the longest Tube line. It is also one of only two lines on the Underground network to cross the Greater London boundary, the other being the Metropolitan line. One of London's deep-level railways,
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