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 1986 Stock consultation results show that the blue prototype was the favoured, and provided the core design basis for the 1992 Stock that was built for London Underground's Central line and Network SouthEast's Waterloo & City line. London Underground 1986 Stock The London Underground 1986 Tube Stock consisted of three prototype electric multiple units built for London Underground that led to the development of the 1992 Stock. In 1984, London Transport ordered three different prototype trains to test new materials, construction methods and seating layouts. Two were built by Metro-Cammell at its Washwood Heath factory, and the third by British Rail Engineering