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
Suicide on the London Underground rushes on overhead". A study of 58 cases showed that the presence of a suicide pit halved the number of deaths. Another safety mechanism are platform edge doors (PEDs), which separate the train from the passengers. These are installed exclusively at the below-ground stations of the Jubilee Line Extension. PEDs are expensive to install and can fail to open, adding a potential reliability problem to train services. Alison Wertheimer wrote in 2001 that there were 100–150 suicides annually on the Underground. The annual number of suicides in the 1940s was 25, increasing to 100 by the 1980s, which, according to