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
East London line extension East London line extension The East London line extension (ELLX) project was a British railway engineering project in London, managed by Transport for London. The project involved extending the East London Line (formerly part of the London Underground network) and making it part of the mainline London Overground network. This was done by re-opening sections of disused railway line and by converting track electrified by the third-rail system, signalling, lineside signage and communication systems, etc. to mainline standards. New rolling stock was introduced and four new stations built along the route, with a fifth scheduled to be added in the