London Underground infrastructure Tube Programme, investigating replacing the trains for the Bakerloo and Piccadilly lines, is looking for trains with better energy conservation and regenerative braking. The Underground serves 270 stations. Fourteen Underground stations are outside Greater London, of which five (Amersham, Chalfont & Latimer, Chesham, and Chorleywood on the Metropolitan line and Epping on the Central line) are beyond the M25 London orbital motorway. The longest distance between two stations is between Chalfont & Latimer and Chesham on the Metropolitan line. The shortest distance between adjacent stations is the between Leicester Square and Covent Garden on the Piccadilly line. The station furthest
London Underground 2009 Stock FICAS technology, giving a thinner bodyshell and hence (along with the larger size) more internal space for passengers. They are the first London Underground trains to be designed since the Rail Vehicle Accessibility Regulations were introduced, so they have more facilities for people with impaired mobility, including multi-purpose areas with tip-up seats and space for wheelchairs and pushchairs, and offset centre door poles for wheelchair access. The trains were the longest deep-level tube trains on the system when introduced, at , longer than the 1967 Stock. The more recently introduced sub-surface S Stock, which is also part of Bombardier's Movia