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 1972 Stock London Underground 1972 Stock The London Underground 1972 Stock is a type of rolling stock used on the London Underground. The 1972 Stock was ordered to make up the shortfall in trains on the Northern line's 1959 Tube Stock fleet. It is, however, currently used on the Bakerloo line. Following the withdrawal of the A Stock on the Metropolitan line in 2012, and the C Stock on the Circle, District and Hammersmith & City lines in June 2014, these trains are now the oldest trains on the London Underground and also on any rapid transit system in the United Kingdom.