Editing Advanced Passenger Train (section)

{{Short description|Experimental tilting high speed train developed by British Rail}}
{{Essay-like|date=October 2023}}
{{Use dmy dates|date=September 2020}}
{{Infobox EMU
| name = Advanced Passenger Train
| image = Advanced Passenger Train at Preston Station.jpg
| caption = APT-P at Preston station.
| yearconstruction = 1970  (APT-E) <br>1977–1980 (APT-P)
| manufacturer = [[British Rail Engineering Limited|BREL]] and [[British Rail Research Division]]
| family = APT
| operator = [[InterCity (British Rail)|InterCity]]
| formation = 14 cars per trainset (APT-P)<br>4 cars per trainset (APT-E)
| numberbuilt = 3 trainsets (APT-P)<br>1 trainset (APT-E)
| weight = 
| height = 
| maxspeed = {{ubl|class=nowrap|
 |'''Service:'''
 |{{convert|125|mph|abbr=on|round=5}}
 |'''Design:'''
 |{{convert|155|mph|abbr=on|round=5}}
}}
| lines = [[West Coast Main Line]]
| stocktype = 
| service = 1972–1976 (APT-E)<br>1980–1986 (APT-P)
| electricsystem = 
| uicclass = 
| gauge = {{track gauge|sg|allk=on|al=on}}
}}
The '''Advanced Passenger Train''' ('''APT''') was a [[tilting train|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 contains 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 [[British Rail APT-E|APT-E]] achieved a new British railway speed record on 10 August 1975 when it reached {{convert|152.3|mph}}, only to be surpassed by the service prototype [[British Rail Class 370|APT-P]] at {{convert|162.2|mph}} 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 [[InterCity 125|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.

Despite the challenges faced by the APT, its design was highly influential and directly inspired other high-speed trains, such as the [[Pendolino]]. The extensive work on electrification carried out alongside the APT was effectively utilized in later non-tilting designs, including the [[British Rail Class 91]]. The APT’s tilting system was reintroduced on the [[West Coast Main Line]] with the [[British Rail Class 390]], which was based on the [[Alstom Ferroviaria|Fiat Ferroviaria]] tilting train design and built by [[Alstom]]. However, certain features introduced by the APT, such as the hydrokinetic braking system, have not been widely adopted.