Advanced Passenger Train

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Advanced Passenger Train
APT-E in the RTC sidings between tests in the summer of 1972
In service	1972–1976 (APT-E) 1980–1986 (APT-P)
Manufacturer	BREL and British Rail Research Division
Family name	APT
Constructed	1970 (APT-E) 1977–1980 (APT-P)
Number built	3 trainsets (APT-P) 1 trainset (APT-E)
Formation	14 cars per trainset (APT-P) 4 cars per trainset (APT-E)
Operators	InterCity
Lines served	West Coast Main Line
Specifications
Maximum speed	Service: 125 mph (200 km/h) Design: 155 mph (250 km/h)

The Advanced Passenger Train (APT) was a tilting high speed train developed by British Rail during 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 been copied 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 surpassed by the service prototype APT-P at 162.2 miles per hour (261.0 km/h) in December 1979.

Development of the service prototypes 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. The election of Margaret Thatcher brought matters to a head and she alluded to funding cuts for the project. Facing the possibility of cancellation, BR management decided to put the prototypes into service, with the first runs along the London–Glasgow route taking place in December 1981.

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. All support for the APT project collapsed as anyone in authority distanced themselves from what was being derided as a failure. Plans for a production version, APT-S, were abandoned, and the three APT-Ps ran for just over a year before being withdrawn again over the winter of 1985/6. Two of the three sets were broken up, and parts of the third sent to the National Railway Museum where it joined the APT-E.

In spite of the APT's troubled history, the design was highly influential and directly inspired other high speed trains such as the Pendolino. The considerable work on electrification that was carried out hand-in-hand with APT was put to good use with newer non-tilting designs like the British Rail Class 91. The APT's tilt system was returned to the WCML on the British Rail Class 390, based on the Fiat Ferroviaria tilting train design and built by Alstom. Other features pioneered on APT, such as the hydrokinetic braking used to stop the train within existing separations, have not been adopted.