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 K Stock London Underground K Stock London Underground K Stock is a clerestory-roofed rail stock built for the District line in 1927. It was subsequently absorbed into the London Underground Q Stock. A complete review of District line rolling stock was carried out in 1926, leading to the withdrawal of further B Stock cars and their replacement, plus additional rolling stock to increase frequencies. This led to the construction of the K Stock, some of which was owned by the London, Midland and Scottish Railway (LMS). As built, the cars had hand-operated sliding doors. The doors were converted to air operation in