Rail Ramble : Happy 40th HST!

Mike Humble:

In original livery - An HST set on the Midland Mainline near Chesterfield on the long drag up the bank to Sheffield.
In original livery – An HST set on the Midland Mainline near Chesterfield on the long drag up the bank to Sheffield.

In a world where four wheels is good, I invite you to take a few minutes out to celebrate the only serious threat to the passenger car in the `70s – the HST or otherwise known as the High Speed Train.

It was this week a staggering 40 years ago that production started at B.R.E.L (British Rail Engineering Ltd) in Crewe on the most iconic and legendary passenger train this side of Gresleys world famous A4 steam locomotive. Even though a prototype HST had been plying its trade as early as 1972, certain design aspects were found to be below expectations. The production HST featured a super sleek aerodynamic cab styled by Terrence Grange, revised cab controls and numerous other incidental and mechanical updates thanks to information gleaned from intensive prototype running experience.

Today, the mass majority of the total build which was completed by 1982 still swoosh by on our privatised and fragmented rail network at over two miles a minute. This fact is all the more amazing when you consider it was only ever intended to be a stop-gap design until the doomed Advanced Passenger Train (APT) came on-line. The HST was designed by a “splinter group” of old school engineers who scoffed at the British Rail Board (BRB) plans of an all singing, all dancing and all tilting express passenger train. An experimental department had been set up in Derby back in the late `60s with some of the best engineering talent being recruited from the automotive and aviation industry.

The battle for supremacy seen at Swindon. The prototype HST alongside the prototype Leyland Gas Turbine APT-P... the latter suffered a slow and lingering death.
The battle for supremacy seen at Swindon. The prototype HST alongside the prototype Leyland Gas Turbine APT… the latter suffered a slow and lingering death. (Image: Courtesy of Traintesting)

But more traditional engineers claimed to be able to provide the BRB with an express passenger train capable of 100+mph running with superior acceleration and the ability to adhere to stop within existing signalling constraints at 125mph better than a Class 55 (Deltic) could at its 100mph limit. Maybe the BRB had doubts of the APT from the outset as they soon gave the go-ahead for what was simply known as The High Speed Train. Great rivalry soon spread amongst the ranks in Derby as the race was on for rail supremacy. The APT offered a passive tilting system, gas turbine propulsion (from British Leyland) articulated bogies and space age aluminium construction – proper stuff of science in every sense.

The HST on the other hand, despite its modern streamlined appearance, offered nowhere near the same level of scientific and dare it be said… unproven technology. A locomotive unit at each end hauling a rake of air conditioned coaches with air suspension and disc brakes was as lavish as it got. Of course it was modern at that time but it was technology that was very much feasibly possible in theory, all it needed was refining with a little fine tuning to get it just right. Progress on the HST was carried out with incredible progression and bear in mind there was no fancy software to predict simulation or outcome and what computers were available featured huge reels of tape and clunky bake-o-lite knobs.

The Derby boffins pose here at York in 1973 to commemorate to completion of high speed endurance testing on the East Coast Mainline. During these trails the world speed diesel traction speed record was broken at over 143mph
The Derby boffins pose here at York in 1973 to commemorate the completion of high speed endurance testing on the East Coast Mainline. During these trails the world speed diesel traction speed record was broken at over 143mph

From the first rough sketches and discussions through to the first proving run of the prototype train took under two years. Barely one year later in mid-June 1973 the prototype HST No: 252001 broke the World speed record for diesel traction between Darlington and York reaching 143.2mph. It stayed on the Eastern Region until May 1975 by which time it had operated for over 100,000 miles. After more intensive proving on the Western region, service and performance data was being constantly fed back to Derby and the BRB pushed the button allowing full scale production despite some initial Union friction over the cab design and insistence of two man running with higher wages for higher speeds.

So what we ended up with and now know instantly as the HST back then was not only a complete success in design / engineering practice but revolutionary in changing the public perception of British Rail. Once passenger services started it was not uncommon to find people happy to stand all the way to their destination just to experience travelling at over two miles per minute in air suspended air conditioned luxury. The APT in gas turbine form was soon cancelled – partly because of BL losing interest in gas turbine propulsion thus the HST became the backbone of the Inter-City brand. Passengers old and young adored them and train drivers battled to get onto the waiting list to drive these new steel wheeled wonders.

Doncaster 1980. An Eastern Region HST departs passing
Doncaster 1980. An Eastern Region HST departs and passes “The Plant” – birthplace of locomotives such as Mallard and The Flying Scotsman.

Over the years I have heard some heart-warming and smile inducing anecdotes about various antics and experiences at the controls of a HST in the days before black boxes and GPS tracking devices, one of the best goes as follows:

“I started on the footplate just as steam was sighing its last hiss and then progressed onto the mighty Deltics, great as they initially were, towards the end of their reign they were cold in winter, hot in summer and mechanically knackered – not to mention rattling every bone in your skeleton on poor track. The HST was mind-blowing to the driving crew and after a while you got to know which ones were better than others. Just like the steamers I cut my teeth on, each set had its own character and quirks and you adapted your driving style accordingly. An HST set with quick reacting brakes and a good response to power input made a relatively monotonous job a pleasure to undertake.

A well prepared HST set allowed you to brake that little bit later and accelerate quicker than your training had ever dictated but they were forgiving machines to command too. I recall leaving Darlington some five or six minutes late owing to the bloody guard alighting to buy cigarettes or something like that from the WH Smiths platform shop. Well we shot through Northallerton as if we were on fire and I noticed an indicated 135 on the clock. A few miles further along we went over the points at Thirsk so fast that my thermos flask jumped off the desk and soaked my trousers with hot coffee.

It must have been felt back in the coaches too as the aforementioned guard started pressing the communication buzzer in a mad frenzy like morse code – we were signal checked just outside York such was our early arrival. Very fast running was by no means unheard of by experienced drivers, but I must stress that we knew what both our own personal abilities and the trains limits were!

 The class 43 was lovely and InterCity was a respected brand, the loco’s were terrific machines – they really were and my one remaining memory is the trembling vibration in the cab that made your keys jingle as the framework took up the immense torque of the engine after you tapped up to notch five (maximum power) on a speedy departure. That and a melodic whine from the traction motors from around 50mph upwards.

Although largely replaced on the East Coast by the alarmingly rapid Class 91Electra, the new breed took many years before they became a reliable racehorse whereby the HST just worked straight out of the box if you like and they had soul… all seventy nine litres of it… screaming away just a few feet behind your backside. They were times with memories I shall forever treasure”

G.E Hutton – Driver – Inter-City (Eastern Region) – now retired.

On the whole, the HST fleet tended to be fairly reliable when operated and serviced properly, but as timetables were squeezed maintenance quality could fluctuate and reliability became open to question. The unusually hot summer of 1983 caused some chronic HST failures with exploding turbo chargers and fatal engine faults owing to overheating. British Rail held the blame squarely at the engine manufacturer – Paxman of Colchester. To combat a serious overheating fault the engines were fitted with a high water temperature shut off device (HWT). If the engine coolant reached a critical level the device would be triggered which automatically shut down the offending engine before any serious harm was done.

This safety device was also a double edged sword as the remaining engine would then be required to work the whole train plus a 70 tonne dead weight of a non functioning locomotive. If the driver failed to nurse the poorly train for the rest of the journey the remaining engine would be strained and shut down thus rendering the whole train a failure, in rail-speak this is known as a “cripple”. Faced with the prospect of legal action Paxman undertook some thorough investigation both in house and shadowing BRs own depot traction fitters. It soon became apparent that the Lion’s share of the huge upturn in engine failures was down to insufficient cleaning of the radiator cooling group. Oil mist and other debris would block up the fins of the massive radiators thus reducing its efficiency considerably.

The original beating heart of the HST. A reconditioned Paxman Valenta 12RP200L diesel - all 79 litres and 2500bhp of it. (Img: GEC Diesels)
The original beating heart of the HST. A reconditioned Paxman Valenta 12RP200L diesel – all 79 litres and 2500bhp of it.           (Img: GEC Diesels)

Also noted was that in some cases the HWT devices had been isolated while in Paxmans own laboratory conditions it was found that in extreme temperature conditions gasket compound used in some areas of engine build would break up. This would float around in the coolant jacket and when temperatures dropped again would cause blockages in the radiators or cylinder heads that would lead to wreckage of the cylinder liners and piston distortion sometimes ending up with a scrap engine. Turbo chargers would crack due to heat but this component was always the weak link – it was not uncommon for a tired turbo to cause spectacular white smoke effects. A worst case scenario would be for the turbo to disintegrate and the engine try to ingest the components – once again… another engine scrapped.

An interesting conversation with a retired rail application engineer went something like this:

We were summoned in front of the board (BRB) and it was rather like waiting to see the headmaster and once beckoned inside the room they wasted no time in venting their frustration and anger at the rate of engine failures the HST fleet was experiencing. They were very seriously threatening us with legal action for loss of revenue but were initially negative towards our suggestion of shadowing their depot fitters. They had this frustrating attitude of “BR knows best” but we stood our ground, they reluctantly backed down and allowed us to go ahead and undertake our investigations.

At first we couldn’t work out why this was happening as we had worked closely with radiator specialists Marston to develop a unique cooler group with a surface area not much smaller than a squash court. It was purpose built for rail usage and was stringently tested for the kind of intensive thermal cycles a locomotive would experience such as long periods of idling after equal periods of maximum power and vice versa.

It wasn’t long before we showed them solid proof of inadequate cleaning, poor preventative maintenance, wrongly specified or incorrectly measured coolant additives, HWT devices either not functioning or disconnected altogether and leaking pipework. As you can imagine we left them with egg on their faces but they worked with us rather than against us and we soon had a working team between us both and strict regimes were implemented that dramatically improved the situation almost overnight

Anon – Retired engineer – GEC Paxman Diesels Limited Colchester

The mid `90s brought privatisation as can be seen here at York with this Great North Eastern HST set.
The mid `90s brought privatisation as can be seen here at York with this Great North Eastern HST set.

After that slight blot of the BR copybook the HST went on to offer superb service not only in the UK but in Australia also. Down under, the Inter-City XPT was a revised and modified HST and coach design developed especially for the Australian climate with down rated engines built locally by the Commonwealth Engineering Co in Granville and Melbourne NSW. But back home in the UK, the HST continues to give a good account for itself in a privatised rail network. Inter-City has given way to eight private operators and despite the design being the age that it is, it still stands as a byword of high speed rail travel born in an era that truly was the age of the train.

Work is underway and plans are afoot for a new breed of diesel powered high speed trains, of course we have the Voyager and Super Voyager class already but will they be rattling along the up and down fast lines forty years from now? I very much doubt it. One thing has been proved and that’s the HST was in every way the high watermark of British railway design excellence and just like that other great British transport icon – Concorde… I will bitterly miss them when they are gone.

Happy 40th HST!

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