The Advanced Passenger Train (APT) was a tilting high speed train developed in the 1970s and early 1980s for use on the West Coast Main Line (WCML). The WCML contained many curves, and the APT pioneered the concept of active tilting to address these, a feature that has since appeared on designs around the world. The experimental APT-E achieved a new British railway speed record on 10 August 1975 when it reached 152.3 miles per hour (245.1 km/h), only to be bested by the service prototype APT-P at 162.2 miles per hour (261.0 km/h) in December 1979, a record that stood for 23 years.
Development dragged on and by the late 1970s the design had been under construction for a decade and the trains were still not ready for service. Facing the possibility of cancellation after the election of Margaret Thatcher, it was decided to put the prototypes into service, with the first runs along the London-Glasgow route taking place in December 1981. Problems plagued the design and the trains were withdrawn from service by the end of the month.
The problems were eventually solved and the trains quietly reintroduced in 1984 with much greater success. By this time the competing High Speed Train, powered by a conventional diesel engine and lacking the APT’s tilt and performance, had gone through development and testing at a rapid rate and was now forming the backbone of BR’s passenger service. Support for the APT project faded and wo of the three sets were broken up, and parts of the third sent to the National Railway Museum where it joined the APT-E. The patents for the APT’s tilt system were sold to Fiat.