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
Central line (London Underground) by escalators. The Central London Railway was absorbed into the Underground Group on 1 January 1913. In 1911, the Great Western Railway won permission for a line from Ealing Broadway to a station near to the CLR's Shepherd's Bush station, with a connection to the West London Railway, and agreement to connect the line to the Central London Railway and for the CLR to run trains to Ealing Broadway. Construction of the extension from the CLR to Ealing Broadway started in 1912 but opening was delayed by World War I. The CLR purchased new rolling stock for the extension, which