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
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