Teething issues that plagued the HST + MK3 sets

[YourMum666]

For older members on the forum, do you recall any serious teething issues in the HST which affected reliability when the units first entered passenger revenue, and if so which ones

 

[Snow1964]

The lack of engine cooling, it was rather close to its limit in the power output of the Valenta engines. I think it was more a summer problem and had to be modified

I vaguely remember in the early days, plan was to use shore power at termini, hence the lift up flap below the lights and horns, clearly didn't work well as soon abandoned.

I think the inter carriage doors originally used a switch in the carpet mats, but it would sometimes not open doors automatically. The idea was could walk to the buffet and carry drinks without needing to operate door buttons.

 

[Graham H]

The lack of engine cooling, it was rather close to its limit in the power output of the Valenta engines. I think it was more a summer problem and had to be modified

I vaguely remember in the early days, plan was to use shore power at termini, hence the lift up flap below the lights and horns, clearly didn't work well as soon abandoned.

I think the inter carriage doors originally used a switch in the carpet mats, but it would sometimes not open doors automatically. The idea was could walk to the buffet and carry drinks without needing to operate door buttons.

Yes I remember the opening doors. A great idea but a real pain in the wotsit if you had spotters in the vestibules going from side to side I know.....I was one ! The smell of the brales was pretty awful too

 

[hexagon789]

For older members on the forum, do you recall any serious teething issues in the HST which affected reliability when the units first entered passenger revenue, and if so which ones

Brakes - both pad material (originally contained asbestos, so was changed for an all organic pad but getting the right material took some time) and also discs cracking. The original design of discs on the power cars in particular suffered badly from thermal cracking, this lead to the now familiar 'split' disc being adopted.

 

[Strathclyder]

The lack of engine cooling, it was rather close to its limit in the power output of the Valenta engines. I think it was more a summer problem and had to be modified

The excellent Paxman History website dives into this issue of the Valenta's cooling issues, particularly during the summer (the summer of 1983 in particular brought these issues into sharp relief), in it's section on the HST, under the sub-section titled 'Thermal Cycling'.

Link here: https://www.paxmanhistory.org.uk/paxrailt.htm#ic125

 

[Peter Mugridge]

There was also the issue of exhaust covering the windscreens as the aerodynamics at the back of the train dragged it down. This was solved by placing a raised sheet just above the roof between the exhausts and the cab; this ensured a layer of clean air was dragged down and kept the worst of the exhaust off the windscreens.

 

[trebor79]

I remember it wasn't uncommon to see small bowsers of coolant at larger stations, for topping up HST power car coolant levels.

 

[Helvellyn]

The ride quality and noise in the Driving Motor Brake (aka Power Car) was so poor for the Guard that it led to the development of the TGS (Trailer Guard Standard).

 

[43096]

I vaguely remember in the early days, plan was to use shore power at termini, hence the lift up flap below the lights and horns, clearly didn't work well as soon abandoned.

That was probably more to do with diagrams being tightened up, reducing turnround times at termini and therefore enabling more trains to be HST formed (or free up HSTs to resource the MML, for example). The shore supply has been used throughout the fleet's life on depots, so there was no issue with it.

 

[coppercapped]

A couple of other things...

...the swinging arms locating the axle boxes to the frames of the BT10 bogie on the Mark III coaches tended to crack underneath the axleboxes. In the early days almost all of them had white residues of the crack detecting fluid clearly visible. The issue was solved by increasing the depth of the casting where it passed under the axlebox and a retro-fitting action saw all the castings of the initial design replaced within a couple of years.

Regarding the brake smell — a flap was fitted to the inlet of the air conditioning system which closed when the brakes were applied. It worked quite well as I remember.

The contamination of the windscreens wasn't ever really solved until the Valentas were replaced by the MTU engines. At many stations, Reading being one, a bucket of water and a brush/mop on a long handle was placed on the platforms at the point where the power cars stopped so the driver could get out and wash the windscreen. It also helped against squashed flies...

But all in all BR got a very good return over the years for the £800,000 it spent on the design, development and construction of the prototype High Speed Diesel Train as it was then known.

 

[Shaw S Hunter]

The excellent Paxman History website dives into this issue with the Valenta's cooling issues, particularly during the summer (the summer of 1983 in particular brought these issues into sharp relief), on it's section on the HST, under the sub-section titled 'Thermal Cycling'.

Link here: https://www.paxmanhistory.org.uk/paxrailt.htm#ic125

That linked to article is excellent, I would recommend all readers of this thread also read the article. It not only confirms in some detail many of the issues that were only described in outline at the time, it also busts one or two myths about poor design. Reality was that the HST project had a much smaller R&D budget than did the APT yet delivered a train that was a huge part of sustaining BR finances until such time as both politicians and the wider public were ready to develop the potential that rail had (and still has) to provide a useful function within the wider economy.

 

[43096]

That linked to article is excellent

It is, but the identity of one of the world record breaking power cars is wrong: it is 43159 not 43104 that has the claim to fame.

 

[Irascible]

The brakes just stank, and the interior doors worked ok until someone put a suitcase on the sensor... I vaguely remember the cooling problems ( I was what, 6 the first time I got on one ) but they seemed quite reliable form the start, had a few journeys over the years with a failed power car, but not many, and I can't remember aircon failing. I think I got turfed off one set at some point because something important had gone u/s but that's it. Then again when what they replaced ( 50s ) had a habit of breaking down every other journey...

 

[The Crab]

Brakes - both pad material (originally contained asbestos, so was changed for an all organic pad but getting the right material took some time) and also discs cracking. The original design of discs on the power cars in particular suffered badly from thermal cracking, this lead to the now familiar 'split' disc being adopted.

What kind of "Organic" material was used?

 

[delt1c]

As much as i loved them the brake smell was bad, interestingly LHS Mk3 didnt have this problem. wonder if they had different brake pads

 

[trebor79]

As much as i loved them the brake smell was bad, interestingly LHS Mk3 didnt have this problem. wonder if they had different brake pads

Yes I think this is correct. The HST brakes were different to allow them to operate at 125mph on lines where the signals were spaced for 100mph operation of conventional loco hauled stock.

 

[nw1]

That was probably more to do with diagrams being tightened up, reducing turnround times at termini and therefore enabling more trains to be HST formed (or free up HSTs to resource the MML, for example). The shore supply has been used throughout the fleet's life on depots, so there was no issue with it.

Looking at both the 1981 and 1989 CWNs for Paddington (available on the brcoachingstock groups.io), some HST workings are marked "connected to shore supply" and some are not.

In 1989 the turnaround times at Paddington were still quite generous - there was no set pattern, but around 40-60 mins was typical and there were a few examples of over an hour (e.g 1102 in from Bristol formed 1230 out). Perhaps a little less than 1981 (also on groups.io) but not significantly.

 

[hexagon789]

What kind of "Organic" material was used?

Can't remember off the top of my head - 'ferrous-' something. I'll try and find out where I saw it.

Yes I think this is correct. The HST brakes were different to allow them to operate at 125mph on lines where the signals were spaced for 100mph operation of conventional loco hauled stock.

The EP feature is the only difference between HSTs and LHCS Mk3 rakes in terms of braking.

The trailers and coaches themselves are no different in terms of equipment being standard UIC twin-pipe air.

Both the original types of WSP could be found on either and both were 125mph plated.

The lack of EP assist in brake applications is one of the reasons the LHCS vehicles never normally ran at more than 110 in service. Similarly if the E70 brake unit failed in either power car, meaning no EP assist, then an HST was limited to 110mph.

There is the added complication that the LHCS Mk3s had their braking rates reduced in the late-70s until 1984 to reduce excessive brake pad wear in mixed sets, but once 110mph running came in the original settings were restored.

 

[The exile]

Whatever the cause of the brake pong was - this small child was convinced that the smell was directly linked to the introduction of burgers in the buffet cars!

 

[nw1]

Incidentally a general question which is a follow-up from my previous post, and is tangentially related.

It does appear, from the 80s CWNs I referred to above, that there was no particular pattern in HST diagrams, in the sense that an arrival into Paddington on route A did not always, or almost always form a departure on route B. Turnaround times varied significantly. It was a bit more predictable in 1978 (also on groups.io), early on in the HST era. I presume the diagrams were setup with fuel usage in mind, which might necessitate different patterns during the day?

 

[Peter Mugridge]

As much as i loved them the brake smell was bad, interestingly LHS Mk3 didnt have this problem. wonder if they had different brake pads

I've noticed the exact same smell ( which for some reason I've never found to be all that bad ) on occasion in other Mk3 vehicles, including 317s, 321s and Chiltern Mk3s ) so certainly not confined to HSTs although most definitely very much more common on them.

 

[Bletchleyite]

As much as i loved them the brake smell was bad, interestingly LHS Mk3 didnt have this problem. wonder if they had different brake pads

It certainly did happen in WCML Mk3 LHCS.

== Doublepost prevention - post automatically merged: 10 Mar 2023 ==

Whatever the cause of the brake pong was - this small child was convinced that the smell was directly linked to the introduction of burgers in the buffet cars!

Eating used brake pads would probably be more appetising than BR microwave gristleburgers!

 

[Trackman]

Eating used brake pads would probably be more appetising than BR microwave gristleburgers!

Leave them alone! I loved them. I used to call them 'Stoke' or 'Watford' Burgers on the WCML because of the length of time you had to wait for them to cool down. They only stuck them in the microwave for a minute so gawd knows what the wattage of the microwave oven was.

The lack of engine cooling, it was rather close to its limit in the power output of the Valenta engines. I think it was more a summer problem and had to be modified

There was an article in RE (now Rail - I think) about this called 'The HST's long, long hot summer' it was a very good write up about the problems.

 

[OVS Flatbottom]

It certainly did happen in WCML Mk3 LHCS.

I'm fairly sure I can remember smelling the brakes on the descent of Beattock in a Mk3 sleeper. Of course, it didn't help that the air conditioning seemed to be blowing right up my nose (I was in the lower berth)...

 

[Western 52]

Another problem the HSTs had were the regular breakages of the headlights. Eventually they were modified to solve the problem. I even made a broken light on my OO HST to make the model more realistic!

 

[bishdunster]

One maker of brake linings/shoes for the automotive industry was called "FERODO", Their adverts were often painted on steel railway overbridges, i wonder if this was the firm concerned?

 

[randyrippley]

I can remember a report in the press which blamed the smell on brake pads made of ABS plastic (acrylonitrile-butadiene-styrene), but in retrospect that seems unlikely due to it going soft at around 80C
Seems more likely the author got confused over the phrase ABS (= anti-lock braking system)

What may be relevant is around then the first sintered metal disk brake pads were being developed for cars and bikes, these had the advantage of being much less affected by rain

 

[Welly]

I've noticed the exact same smell ( which for some reason I've never found to be all that bad ) on occasion in other Mk3 vehicles, including 317s, 321s and Chiltern Mk3s ) so certainly not confined to HSTs although most definitely very much more common on them.

My VW clutch must be made of the same material as well - sometimes I smell the exact same smell if I slip my clutch too long.

 

[PG]

My VW clutch must be made of the same material as well - sometimes I smell the exact same smell if I slip my clutch too long.

Best avoid that if you want to keep your repair bills down...

Talking of bills I remember hearing it said when the HSTs were still new that every time they applied the brakes they burnt a £5 note but I don't think it was related to the smell! For the benefit of our younger readers - £20 note nowadays.

 

[Halish Railway]

It certainly did happen in WCML Mk3 LHCS.

It still does on some of the Chiltern Mk3s.