HST.. The Intercity 125

The first production car, 43002 was delivered in 1975. Rumour had it that the HST was a stopgap measure until the AP-T was perfected. It never happened and the HST became the star of British railways

The speed limit on the rails at the time was 100mph, but the light axle loading of the HST allowed for 125mph. It was and still remains the fastest diesel powered passenger service in the WORLD, setting a record of 143.2mph in 1973.

Power was delivered by two power cars, one at each end, Each end was fitted out with a Paxman Valenta 12 cylinder marine diesel engine developing 2,250hp, but due to overheating problems was eventually reduced to 2000hp. Since 2005, HSTs have been refurbished with Paxman VP185 engines

The prototype had a look all of its own, not the prettiest look for a streamliner. This is 41001 on display at the National Railway Museum in York. The buffers look decidedly out of place, and lights are close grouped behind glass in the centre..Also note that there was no provision for a view out of the sides for the driver.

The final design was a little more raked, side windows were added, the buffers disappeared and the lights were spread out and in their own nacelles, an altogether more pleasing look.

Why diesel? Well, the only overhead electrified lines ran down the West Coast main line originally. The East Coast main line didn’t get converted until the 80’s. The Western region was also not electrified, so it made sense to produce a ‘one size Diesel fits all’ The UK was up to this point lagging behind the rest of Europe in high speed trains. The lack of overall electrification and the more traditional train sets made up of Class 55’s and Mk3 coaches was not cutting any mustard.

Anyway, here is a photo of a production HST, 43058 sitting at Leicester on the East Coast main line pre electrification

The HST is a definite favourite with train spotters, not just for the rakish looks and overall performance, but also for the way its starts up. The Valenta turbocharger is really quite noisy, and standing next to an HST is not unlike standing next to jet aircraft as it powers up for take-off. Watch the video and turn your speakers up..

The HST will not be around forever so make the most of them while you can.