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
History of the London Underground of London and especially the Blitz led to the use of many tube stations as air-raid shelters, with 175,000 people arriving every night in August 1940. Six stations were breached by a direct hit, and in March 1943, 173 people died in a crowd crush accident at the unfinished Bethnal Green station. In the 1940s a depot built for the Northern line extension and an unfinished stretch of the Central line extension, the underground section between Newbury Park and Leytonstone, was turned into aircraft factory. The closed Brompton Road station was used as an anti-aircraft control room. The closed Down