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
South London line South London line The South London line is an Inner London part of the London Overground rail network. The line is run together with the East London line to provide direct services between and . It consists of eight stations, one of which marks the crossover into the East London line network and runs . Most of the line is on high viaduct over other transport infrastructure. Interchanges with the London Underground are at and the closest on its London Overground extension is . The line is in Travelcard Zone 2. From the early 20th century until 2012 a shorter