British Rail InterCity APT

This week, I'd like to share a short documentary film i found on YouTube about the InterCity APT (there are some link on this Wikipedia page that are definitely very much worth a while to visit), a failed experimental high speed train that, however, did not fail to inspire in engineering design of newer generation passenger rail equipment.

The trainset is also known as the APT-P (because she isn't the only experimental APT, see my old post), or classified as the Class 370 by British Railways. At the time, the InterCity APT was intended to be used on the electrified West Coast Main Line between London Euston and Glasgow Central. By now you must wonder what APT stands for-Advanced Passenger Train.

In short, the InterCity APT is an articulated push-pull electric tilting trainset developed by the British Rail Engineering Limited. Non-powered cars on the train share trucks between them, and the cars tilt to a certain degree when the train goes around a curve. The exact amount of tilting required to keep the ride comfortable is determined by sensors and means of computation, this is also referred to as "active tilting" (as opposed to "passive tilting", which you can read about from my post on the Talgo). The IC APT is also very unconventional in a way that her power cars are not on either end, but in the middle of the train. I would speculate that this has something to do with reducing lateral forces and thus rail wear, but it wasn't great since it cut the train in two halves inaccessible from each other by passengers.

The demise of the InterCity APT was caused by a number of reasons that I would rather link you to read about. Some of the technology developed for the APT though did live on in other forms. The APT-P is said to have heavily influenced the design of the Class 91 locomotive on the InterCity 225. The tilting technology was eventually sold to Fiat of Italy (now part of Alstom of France) and was incorporated into their own Pendolino tilting trains, a family which the Class 390 was a member of.

Please enjoy this film.


M-NL said…
The engineers wanted to have only one active pantograph for the entire train set and didn't want a high tension cable running the length of the train, thus it made sense that the 2 motorcars of the 14 car set were joined together and positioned in the middle.

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