page_title: London Underground 1973 Stock
section_title: History
hierarchical_section_title: London Underground 1973 Stock / History
caption_attribution_description: English: Wot? No Commuters? Definitely Off-Peak time at Ealing Common station.
context_page_description: The London Underground 1973 Stock is a type of rolling stock used on the Piccadilly line of the London Underground. It was introduced into service in 1975 with the extension of the line to Hatton Cross, followed by a further extension to Heathrow Central in 1977.
  The trains were built by Metro-Cammell between 1974 and 1977, and were refurbished by Bombardier Transportation between 1996 and 2001. They are some of the oldest trains running on the Underground, second only to the 1972 Stock running on the Bakerloo line.
context_section_description: In the early 1970s London Transport placed an order for a new fleet of trains to replace the 1959 stock, the 1938 stock and 1962 stock vehicles which previously operated on the Piccadilly line. Built between 1974 and 1977 by Metro Cammell in Birmingham, the first unit entered service on 19 July 1975 and the last was introduced by 1977. The trains featured longer cars and larger door space than the previous units, being designed for airport travellers with luggage.
  The order was for 87½ 6-car trains, made up of 196 Driving Motor cars (DM's), 175 Trailer cars (T's) and 154 Uncoupling Non-Driving Motor cars (UNDM's). Each train is made up of two 3-car units, and most units are single-ended, formed DM-T-UNDM. There are also 21 double-ended units, formed DM-T-DM, to provide additional flexibility and to operate the Aldwych shuttle (now closed).
  The initial order additionally included two test units equipped with solid state traction equipment and electronic control systems. These were double-ended units 892-692-893 (delivered 1977) and 894-694-895 (delivered 1979), and were known collectively as the ETT (Experimental Tube Train). The first unit was equipped by Westinghouse, the second by GEC. In order to provide additional units for the opening of the Heathrow loop, these units were converted to standard at Acton Works, entering service between 1986 and 1987.
  One three-car unit (166-566-366) was damaged in a terrorist attack on 7 July 2005 and subsequently scrapped.
caption: 1973 Stock in original livery at Ealing Common
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