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
London Underground infrastructure All of the lines use fixed length trains with between six and eight cars, except for the Waterloo & City line, which uses four-car trains. New trains are designed for maximum number of standing passengers and for speed of access to the cars and have regenerative braking and public address systems. Since 1999, all new stock has had to comply with accessibility regulations that require such things as access and room for wheelchairs, and the size of location of door controls. All underground trains are required to comply with the Rail Vehicle Accessibility (Non Interoperable Rail System) Regulations 2010 (RVAR