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 Options for new trains for the Bakerloo and Piccadilly lines are being considered. Crossrail is under construction and expected to open in 2018, providing a new underground route across central London integrated with the London Underground system. Options are being considered for the route of Crossrail 2 on a north-south alignment across London, with hopes that it could be open by 2033. London Underground infrastructure The infrastructure of the London Underground includes 11 lines, with 270 stations. There are two types of line on the London Underground: services that run on the sub-surface network that is just below the surface