London Underground 1973 Stock

The London Underground 1973 Stock is a type of rolling stock used on the Piccadilly line, introduced into service in 1975 with the extension of the line to Hatton Cross and followed by a further extension to Heathrow Central in 1977. Metro-Cammell built the 86 six-car trains between 1974 and 1977 in Birmingham, and Bombardier Transportation refurbished them between 1996 and 2001. The first unit entered service on 19 July 1975. The trains have longer cars and larger door space than the units they replaced and were designed with extra luggage space for airport travellers. Each train is made up of two three-car units, most single-ended and formed driving motor, trailer and uncoupling non-driving motor, with 21 double-ended units for flexibility.