British Diesels and Electrics: Class 370 APT

The Advanced Passenger Train (APT) project was begun by British Rail in the early 1970s and was supposed to be the future of InterCity travel. Indeed, the High Speed Train which was introduced later in the decade was seen as a bit of a stop-gap! The APT project unfortunately never came to fruition despite over a decade of development and failed to enter service, though the Class 370 electric multiple unit came (fairly) close.

370 003 preserved at Crewe Heritage Centre

Information
Number built:	44 (6 7-car sets - though making 3 trains + 2 spares)
Built:	1977-78
Builder:	BR Derby / ASEA
Engine:	4 ASEA/LJMA 410F traction motors (25kV AC OHLE)
Power:	4, 000 hp (2, 983 kW) (per power car - 2 are used in a train)
Formation:	Driving Trailer Second (DTS)+Trailer Second (TS)+Trailer Unclassified (Restaurant) (TU)+Trailer Buffet Second (TRSB)+Trailer First (TF)+ Trailer Brake First (TBF)+Non-Driving Motor (M)+ [M+TBF+TF+TRSB+TU+TS+DTS]

The Class 370 was built on the experience gained from the gas-turbine powered APT-E in the early 1970s [1]. The Class 370, often referred to as the APT-P, was designed to be able to travel at 125mp/h along the West Coast Main Line, the coaches tilting to allow for the increased speed on legacy tracks. The tilting unfortunately proved the APT's Achilles Heel causing a lot of trouble and technical headaches. The project was finally cancelled in the mid-1985s. It was not a complete waste however as some of the technology developed was later used on the InterCity 225 and also used on the Pendolino sets which now run on the WCML - though these were not built in the UK.

Each of the six Class 370 sets built consisted of seven vehicles, a non-driving motor car and six passenger carrying cars. Two sets made up an in-service rake with the two motor cars being in the centre of the train.

The Class 370 had a number of "interesting" features, notably the train's power cars which had no passenger gangway access meaning that there was no passenger access between the two halves of the train while in motion (and also wasted a lot of platform space). Buffet facilities therefore had to be duplicated. The limitations of the central power cars were well known during testing and the production APT (or "squadron service") version of the train (known as the APT-S) would have had a single power car at one end of the train [2]. In the end this layout is what was used on the Class 91 hauled (and propelled) Intercity 225.

Seven cars have been preserved including a six-car rake at the Crewe Heritage Centre and another Motor car.