Introduced in 1979, the APT-P, as it is normally referred to, was an InterCity Development train, uniquely designed to provide faster journey times on the West Coast Main Line, culminating in a passenger relief service between London and Glasgow three days a week between 1983-85. Then from 1985-87 it was used solely for development purposes of future electric locomotives.
Built by BREL at Derby, the allocation, which was divided between Glasgow Shields Electric Traction Depot and Crewe ETD, consisted of six rakes and spare driving second & brake first vehicles, numbered 370001 - 370007 (Class 370). Each rake would contain up to six articulated trailer vehicles and one non-driving motor vehicle, so that each train set would comprise of two such rakes with the motor vehicles being situated in the centre of the formation.
To meet the criteria for faster journey times the decision between straightening the track and tilting the train over existing track had to be made. The decision went in favour of the tilting train, hence the special features of the APT were developed.
The above items were developed to give a maximum line speed of 155 mph and with tilt the APT could consequently negotiate curves 20%-40% faster than conventional trains.
APT - With Hindsight by Professor A Wickens, formerly Director Advanced Projects, Research Department British Railways Board.
The Great Train Robbery by J Dwyer - The Manufacturer - March 2004.
'Queasy Rider:' The Failure of the Advanced Passenger Train (670KB) by B Goodwin - February 2006.