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 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