Central line (London Underground) 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, Central line trains are smaller than those on British main lines. The line was opened as the Central London Railway in 1900, crossing
Transport in London the National Rail system. There are several extensions planned for the system, such as expanding its coverage and further integrating it into the Underground system. London is the focal point of the British railway network, with 18 major stations providing a combination of suburban, intercity, airport and international services; 14 of these stations are termini and 4 are through stations, while two others are both. Most areas of the city not served by the Underground or DLR are served by suburban heavy rail services into one of these stations. These suburban rail services are not part of Transport for London