As the latter decades of the 20th Century pressed on, a growing road network, which included the introduction of brand new motorways, posed a problem for railways. To redress the balance, the British Transport Commission began exploring how to increase journey times on major intercity routes, which at the time were limited to 100 mph maximum; the Government would not allow any new railways to be built, and so attention was turned on improving current infrastructure and developing a brand new “Advanced Passenger Train”.

Throughout the 1960s, the pioneering work on the tilting, turbine-powered “APT” was subject to continual delays, and passenger numbers had fallen to half of what they were since the end of World War 2. Instead of leaving the railways to waste away to roads completely, it was decided that a new diesel train would be built as a high-speed stop-gap while Britain waited for the APT.

As engineers looked into the new high-speed diesel train, it quickly became apparent that reaching and sustaining the desirable 125 mph would need significant horsepower, and so designs featured a power car at either end of the consist. This approach had several benefits over a single locomotive, no single engine at the time was powerful enough for the job, and so two would be required; however with the increased speeds, routes such as the Great Western Main Line, where the new trains were due to operate, would suffer greatly with a heavy, double-engined locomotive at one end, and so the load was lightened by a two-power car design.

The prototype “High Speed Train” was introduced in 1972, and following testing, began trials on the East Coast Main Line. The ECML provided an opportunity that many other lines did not, continuous stretches of track which would be well-suited for high-speed running. During trials, the new train would continually set new world speed records for diesel traction, 131 mph, 143 mph, drivers thought they’d be able to push the new trains to 150 mph, but British Railways Board soon put a stopper on this record-breaking testing, so that the APT could be promoted as the future of British rail travel.

Nonetheless, the prototype High Speed Train had proven both itself and the fixed-formation concept, and so a total of 27 production HST sets were to be built to revolutionise intercity services between London Paddington and the southwest of England. The production sets would end up looking quite different to the prototype, having been redesigned by Kenneth Grange (who was originally drafted in to just design the livery). Gone were the conventional buffers, replaced by a hidden drawbar, to improve aerodynamics, and the windscreen was enlarged with cab-side windows added. The iconic HST began to take shape.

The first production power car, 43002, was delivered in 1975, and was subsequently followed with the rest of the fleet throughout 1976. The new trains, which at the time were classified as diesel-electric multiple units, the Class 253s, were branded as the InterCity 125, and adorned a suitable variation on the BR Blue & Grey livery. The first 125 mph run for the HST was timetabled for October 1976, and by May 1977, the whole fleet was in service.

The oldest members of the High Speed Train fleet have now entered their 5th decade of service, yet despite their age, they continue to effortlessly work along the Great Western Main Line, up and down the East Coast Main Line, across the Midland Main Line and throughout the Cross Country network. It is estimated that, as of October 2016, most HST sets have clocked some 60,000,000 miles, that’s around two thirds of the way to the Sun!

Above all, even with their replacements, the Class 800, entering service, there are still plans in place which would see the HST operate well beyond 2020; GWR have started operating short sets for Cardiff – Penzance services, CrossCountry will refurbish their fleet, and some displaced units will be working for ScotRail, again as short sets on expresses between Edinburgh, Glasgow, Aberdeen and Inverness.

With Train Sim World, you get the chance to step into the cab of the iconic HST, represented in Great Western Railway livery, and get a taste of what 125 mph looks, sound and feels like. Of course, you can also play the role of a passenger and take a seat in a newly refurbished Mk3, and be whisked along the GWML at journey-shrinking paces.

Experience the might of the HST today, with either Train Sim World: Great Western Express for Windows PC, or Train Sim World: Founders Edition for Xbox One! ■