HST: DMU or LHCS

[pdeaves]

What about the old Gatwick Express 73+Mk2 sets though? AIUI the coaching stock and the DMLVs (if that's the right acronym) each had their own, separate TOPS classifications in the 4xx series.

Yes, Gatwick Express used class 488 non-powered MUs and class 489 driving vehicles. The combined 488/489 was the same concept as the non-powered class 438.

 

[43096]

Yes, Gatwick Express used class 488 non-powered MUs and class 489 driving vehicles. The combined 488/489 was the same concept as the non-powered class 438.

Class 489 was powered, though, and worked in multi with the electro-diesel at the other end.

 

[pdeaves]

Class 489 was powered, though, and worked in multi with the electro-diesel at the other end.

Was the power capability routinely used? - serious question; I have no idea.

 

[Cowley]

Was the power capability routinely used? - serious question; I have no idea.

I’m pretty sure it was. There were problems with the 73s catching fire when it was first launched though, leading to a temporary reduction from eight to five coaches and the 73s being paired up running on diesel while it was sorted out. I’m not sure if the vans were still using the 3rd rail though?
It was all quite flexible on the Southern Region of course.

 

[43096]

Was the power capability routinely used? - serious question; I have no idea.

As I understand it, yes, it was routine.

 

[theblackwatch]

Annoyingly, I didn't record the GLV's for haulage when I did the GatEx 73s. Major bashing failure!

 

[dubscottie]

Yes, a great pair of prototypes. Project shelved for sprinters instead...… A DEMU in the best thumper tradition, similar units were built for Northern Ireland (Class 450?)

The NIR 450 were a mash of old 70 class power units, second hand Mk1 underframes, and new Mk3 style bodies.

Oddly enough, NIR classed two 80 class motor coaches back to back as locos. They hauled freight and loco hauled stock like that.

In a very old book I have (late 50's), a DMU (or DMMU) is a
Diesel, Multiple engined, (Mechanical), Unit.

EMU is Electric, Multiple motored, Unit.

The M does not mean "can work in multiple" .

Anyway, to me HST are DEMUs. They have power cars (Driving Motor) not locos.

If HST were LHCS, the coaches would be numbered as such. But all HST power cars/coaches are numbered in the same sequence.

 

[D6975]

Oddly enough, NIR classed two 80 class motor coaches back to back as locos. They hauled freight and loco hauled stock like that.

I've seen phots of class 70 power cars hauling freight, but never seen a phot of class 80s on freight.

 

[whhistle]

I refer the honourable member to the class 210.

Good! Although not sure prototype counts :P
And it's not exactly a particularly modern comparable unit.

The forthcoming class 755 bi-modes for Greater Anglia will also have above-floor engines.

... which is a bi-mode so not quite DMU.


I suppose another difference that shows the HST is a loco + coaches is that the loco doesn't carry any passengers. I can't think of a DMU that has a loco car that doesn't carry passengers.

Similarly if there's a Class 47 top and tail railtour, is that considered a DMU?

 

[DelW]

In a very old book I have (late 50's), a DMU (or DMMU) is a
Diesel, Multiple engined, (Mechanical), Unit.

EMU is Electric, Multiple motored, Unit.

The M does not mean "can work in multiple".

That's interesting evidence, it seems I've been under a misunderstanding for about 50 years

I found another misunderstanding when looking at an old book yesterday evening: I'd always thought that Blue Pullmans (mentioned briefly earlier in this thread) were a similar layout to a (shorter) HST, but apparently not. The formations aren't very obvious, but they seem to have had traction motors on two of the intermediate vehicles as well as the power cars, so they were definitely DEMUs.

 

[Journeyman]

I found another misunderstanding when looking at an old book yesterday evening: I'd always thought that Blue Pullmans (mentioned briefly earlier in this thread) were a similar layout to a (shorter) HST, but apparently not. The formations aren't very obvious, but they seem to have had traction motors on two of the intermediate vehicles as well as the power cars, so they were definitely DEMUs.

Yes, there were powered bogies on the cars adjacent to the driving cars. The ride on them was absolutely terrible, apparently. Always thought it was a crying shame a set wasn't preserved, though - they looked fantastic, and I bet a three-course meal on one of those was a wonderful experience.

 

[keith1879]

I suppose another difference that shows the HST is a loco + coaches is that the loco doesn't carry any passengers. I can't think of a DMU that has a loco car that doesn't carry passengers.

Similarly if there's a Class 47 top and tail railtour, is that considered a DMU?

I think this is a key issue. The term "multiple unit" in this country has a slightly blurred meaning. Certainly in diesel terms by "DMU" we tend to mean "railcar" .... in the sense that the same vehicle carries passengers and has engines. This was true of all modernisation plan DMUs (although there were some trailer cars of course) and of the blue pullmans. It is not true of the HST. Again EMUs all have motors under passenger compartments these days. I tend to agree with the earlier poster who said that HSTs are HSTs - no more and no less.

 

[DelW]

Always thought it was a crying shame a set wasn't preserved, though - they looked fantastic, and I bet a three-course meal on one of those was a wonderful experience.

Going a bit O/T here, but I agree they were highly futuristic in their day. I have a faint childhood memory of one appearing as an "atomic powered" runaway train in the Gerry Anderson puppet series "Supercar" - from Wikipedia's episode list it must have been episode 1 of series 2 in 1962, which says the train was (bizarrely) running from London to Brighton. I suspect they might have re-used footage from a "London to Brighton in four minutes" film!
I suppose in the early 1970s the preservation groups were too focussed on rebuilding ex-Barry steam locos to attempt diesel preservation, which I think really only got underway in the late '70s when the WR diesel hydraulics were withdrawn.

 

[ccityplanner12]

I don't think the argument of "not designed to multiple with anything" precludes multiple unit status. HSTs are not designed to multiple with anything when in revenue service, but nor are Class 700s.

HSTs are locomotive-hauled trainsets designed to be used like multiple units. They are hybrids rather than strictly one or the other. In my experience whether railfans class them as DMU or LHCS depends on what they have to compare them to.
As far as orthodox diesel haulage bashing is concerned, they do not count as bashable. This has more to do with them lacking the quirks of locomotives which hauled rakes of Mk.1s & 2s, & also the circumstances of their introduction: they were accompanied by an ad campaign which meant civvies liked them, which to any non-millennial teenager would make them instantly uncool, & bashers would also have resented the lack of compartments in which to bellow in peace.
I, however, lead the sad existence a post-Mk.1-native railfan. They had all gone from the network by the time I moved back from the Czech Republic, so the HSTs are some of the oldest trains I can remember riding on the network. To me they are enjoyable to ride. They are much preferable to the horrid 22x DEMUs which are now the dominant train in the Midlands: with their awful ride quality & juddering they are not only the least comfortable long-distance trains in Europe & a national shame, but also incredibly boring. If there are any mercenary time lords reading this post, I recommend that you travel to the early 1980s & move the bashing fraternity into a timeline in which such sorry trains are never built: I'm sure they would pay handsomely for the privilege.

Reading Railforums, the impression I get is that many members have much the same opinion as I do about the HSTs: that they are likeable trains, of some interest & enjoyable to use, but that they would not feature on the opiner's ideal rail network.

 

[D365]

... with their awful ride quality & juddering they are not only the least comfortable long-distance trains in Europe & a national shame, but also incredibly boring.

The Voyagers aren't perfect by any means, but I'll have to disagree on several counts. The salon interiors are far more pleasant than the claustrophobic Pendolinos, and the seats are fine for the job. Certainly they haven't raised complaints in the same manner as the Hitachi trains.

Reading Railforums, the impression I get is that many members have much the same opinion as I do about the HSTs: that they are likeable trains, of some interest & enjoyable to use, but that they would not feature on the opiner's ideal rail network.

Perhaps because (bearing in mind this thread is now 20 months old) the HSTs are very much in the twilight years of their careers. They've done their time, when it comes to frontline service.

 

[hexagon789]

Loco-hauled originally, then DEMUs, then loco-hauled again.

That's how I've always understood it anyway

 

[jopsuk]

That's interesting evidence, it seems I've been under a misunderstanding for about 50 years

I found another misunderstanding when looking at an old book yesterday evening: I'd always thought that Blue Pullmans (mentioned briefly earlier in this thread) were a similar layout to a (shorter) HST, but apparently not. The formations aren't very obvious, but they seem to have had traction motors on two of the intermediate vehicles as well as the power cars, so they were definitely DEMUs.

Also, they has passenger accomodation in the Driving Motor cars. I'd hazard a guess that were there a set or two on preserved lines- or even better, on mainline charter- that these spots would be highly prized by enthusiasts.

 

[Ashley Hill]

I understand GWR class their 255s as units. This is so they can be worked by conductors with much reduced responsibility than that of train managers.

 

[hexagon789]

I understand GWR class their 255s as units. This is so they can be worked by conductors with much reduced responsibility than that of train managers.

It's purely an internal designation though, not an official class on TOPS

 

[jopsuk]

It's purely an internal designation though, not an official class on TOPS

in what way is TOPS more "official" than the TOC's internal diagramming?

Serious question.

After all, when it comes to differential speed limits, another "official" source, HSTs are neither DMUs nor LHCS, although some classes that are definitely DMUs don't count as DMUs for this, but as HSTs. And then some don't count as either.

 

[87015]

in what way is TOPS more "official" than the TOC's internal diagramming?

Serious question.

After all, when it comes to differential speed limits, another "official" source, HSTs are neither DMUs nor LHCS, although some classes that are definitely DMUs don't count as DMUs for this, but as HSTs. And then some don't count as either.

Because you can and do type anything into "official" internal diagrams, it takes about a minute to setup new "stock" type and it doesn't have to go anywhere formal like the stock library.

 

[pdeaves]

See also this thread: https://www.railforums.co.uk/threads/is-there-really-a-class-255-and-class-257.192949/

 

[supervc-10]

I would feel like an MU has passenger accommodation in the same vehicle as the power system or other vital systems, whatever that power system may be. The HSTs don't fit that cleanly, although they do have the van section of the power cars. The Blue Pullman or the diesel Stadler Flirts are very definitely MUs- there are powered bogies under the passenger sections. Same goes for the early TGVs or 373 Eurostar.

HSTs are definitely something of a hybrid between LHCS and MUs. The TGVs and 373s are too- as they have separate power cars with no passenger accommodation, and then some powered bogies under passenger cars, but still also have something that is very definitely a locomotive.

Humans like things to fit into neat boxes. The real world doesn't do that very well.

 

[themiller]

To me, a multiple unit is a set of coaches which are not powered from a separate locomotive but have the engine/motors installed within the set. The HST power car is a locomotive just as Eurotunnel class 9 locomotives of the later batch without the second cab because they can be operated ‘loose’ and cannot carry passengers (I know that they can in emergenices). Of course there are exceptions like the class 373s but in their case the power unit at each end is shared between 2 vehicles one of which carries passengers. We mustn’t forget when the mark 4 coaches were first built, there was a class 91 on one end of the coach rake with a class 43 at the other end (both producing power) so the class 43s are not tied only to mark 3 coaches. An analogy would be in Switzerland, I’ve seen an international sleeper train with a class 460 on the front and another several coaches back also providing power. This does not change the status of the locomotive to no longer being classed as such. Nor are the heavy freights with loco(s) both at the front and rear classes as FMUs (Freight Multiple Units).

 

[pdeaves]

I would feel like an MU has passenger accommodation in the same vehicle as the power system

This neatly highlights that wherever we try to make a definition, exceptions will occur. There are freight multiple units around. The (historic) GWR and BR had parcels multiple units, and of course there are Royal Mail's 325s. I am sure most people would say those are 'multiple units', yet don't have any passenger accommodation.

Perhaps a 'multiple unit' could be whatever you want it to be! Maybe Schroedinger's train - it is both an MU and not a MU until you look at it?

 

[Helvellyn]

Loco-hauled originally, then DEMUs, then loco-hauled again.

That's how I've always understood it anyway

Exactly. The two prototype power cars were originally classified as Class 41 (41001/41002) and worked with the ten prototype Mark 3 coaches:

• RB 10000
• RUK 10100
• FOs 11000-11003
• TSOs 12000-12003

Shortly after construction the decision was made to classify the HST as a DEMU and the prototype set was Class 252, set number 252001 (the Blue Pullman was Class 251). The Mark 3 coaches and the locomotives were all renumbered into the 4xxxx series and gained new diagram numbers commencing G.

• TRB 40000 (ex 10000)
• TRUK 40500 (ex 10100)
• TFs 41000-41002 (ex 11000/11002/11003)
• TSs 42000-42002 (ex 12000/12002/12003)
• DMBs 43000/43001 (ex 41001/41002)

11001 and 12001 would be rebuilt as Royal Saloons 2903 and 2904 for HM The Queen and HRH The Duke of Edinburgh respectively.

Incidentally I have been told this is why despite being built before the production HST fleet the loco-hauled Mark 3s were designated Mark 3A because the prototype vehicles with three-phase heating versus the more usual ETH (now ETS) were Mark 3, which continued with the production builds.

When the production builds were ordered all power cars had Lot No.s issued in the standard BR series used for loco hauled and multiple unit stock. They also got diagram numbers and there were two types:

• 43002-43152 were DMB (Driving Motor Brake)
• 43153-43198 were DM (Driving Motor)

The reason for the difference was that with the fourth batch the Guard's accommodation was moved from the power car to the new TGS (Trailer Guard Standard) vehicles numbered in the 44xxx series - the next in sequence series after the catering vehicles (40xxx), TFs (41xxx), TSs (42xxx) and power cars (43xxx).

The trains were ordered in batches:

• 253001-253027 - 27 2+7 sets for Bristol and South Wales GWML services
• 254001-254032 - 32 2+8 sets for ECML services
  • 43120/43121 built out of sequence as spare GWML power cars
  • 43122/43123 built as spare ECML power cars
• 253028-253041 - 14 2+8 sets for Devon and Cornwall GWML services
  • 43124 built as spare GWML power car
  • 253041 built with one less TS and contained prototype TGS 44000; entered service as a 2+7 NE-SW set (see below)
• 253042-253059 - 18 2+7 NE-SW CrossCountry sets
  • 43189/43190 built as spare power cars for GWML allowing 43120/43121 to move back to ECML as spare
  • 253042-253046 delivered as 254033-254037 2+8 sets for ECML.
• 254033-254036 - 4 2+8 sets for ECML (BR had wanted seven sets)
  • Delivered as 2530xx 2+7 sets for NE-SW services due to the first sets from batch 4 going to the ECML (see above)

Reformations happened from early days, with catering vehicles moving around and then the removal of a TS vehicle from the first 72 sets to be replaced with TGS coaches ordered as part of sets 74-91 (set 73 had the prototype TGS).

Some NE-SW sets started being disbanded in the mid-1980s to replace some Kitchen cars (2 x NE-SW sets), to strengthen some ex-GWML 2+7 sets transferred to the MML (1 x ex NE-SW set) and then to strengthen some GWML sets (1 x NE-SW set). I think it was by the time the third set was disbanded that the decision to stop treating the whole as a DEMU was taken, because with an increased float of spare power cars coupled with declining power car reliability it was increasingly hard to get power cars back into the original set.

If you look at sets in blue/grey they carried the 25xxxx set number on the emergency coupler cover hatch. Early InterCity Executive painted sets kept the set number but in InterCity Swallow colours power cars gained what was now their loco number on the front.

 

[hexagon789]

Incidentally I have been told this is why despite being built before the production HST fleet the loco-hauled Mark 3s were designated Mark 3A because the prototype vehicles with three-phase heating versus the more usual ETH (now ETS) were Mark 3, which continued with the production builds.

The Irish Mk3s are arguably more like HST trailers in that respect having 3-phase ETS though at different voltage

 

[43096]

The trains were ordered in batches:

• 253001-253027 - 27 2+7 sets for Bristol and South Wales GWML services
• 254001-254032 - 32 2+8 sets for ECML services
  • 43120/43121 built out of sequence as spare GWML power cars
  • 43122/43123 built as spare ECML power cars
• 253028-253041 - 14 2+8 sets for Devon and Cornwall GWML services
  • 43124 built as spare GWML power car
  • 253041 built with one less TS and contained prototype TGS 44000; entered service as a 2+7 NE-SW set (see below)
• 253042-253059 - 18 2+7 NE-SW CrossCountry sets
  • 43189/43190 built as spare power cars for GWML allowing 43120/43121 to move back to ECML as spare
  • 253042-253046 delivered as 254033-254037 2+8 sets for ECML.
• 254033-254036 - 4 2+8 sets for ECML (BR had wanted seven sets)
  • Delivered as 2530xx 2+7 sets for NE-SW services due to the first sets from batch 4 going to the ECML (see above)

A neat summary!

The delivery from 253041 onwards was re-jigged, so that the power cars for 253041 (43151/152) became the spares that 43189/190 had been intended as, and the extra 4 East Coast sets were prioritised for delivery and delivered as 5 sets (power cars 43153-162), with the NE-SW shuffled backwards. In effect, the original 253041 was eventually delivered as an extra East Coast set. I suspect that the swap-round of 43151/152 and 43189/190 as the spare power cars was to avoid giving 43151/152 to the Eastern Region, which would have left them with those two as oddballs by virtue of their GEC traction motors. What didn't help was that Crewe continued to outshop the power cars with their originally intended set numbers on the front hatch rather than in accordance with the revised delivery plan - a fact "theblackwatch" of this parish pointed out to me.

The list below shows how it changed. First column is power car number, then intended set, then as actually delivered. 43193-198 went almost immediately after delivery to the ER and spent little, if any, time on NE-SW workings.
43151 - 253041 - Spare
43152 - 253041 - Spare
43153 - 253042 - 254033
43154 - 253042 - 254033
43155 - 253043 - 254034
43156 - 253043 - 254034
43157 - 253044 - 254035
43158 - 253044 - 254035
43159 - 253045 - 254036
43160 - 253045 - 254036
43161 - 253046 - 254037
43162 - 253046 - 254037
43163 - 253047 - 253041
43164 - 253047 - 253041
43165 - 253048 - 253042
43166 - 253048 - 253042
43167 - 253049 - 253043
43168 - 253049 - 253043
43169 - 253050 - 253044
43170 - 253050 - 253044
43171 - 253051 - 253045
43172 - 253051 - 253045
43173 - 253052 - 253046
43174 - 253052 - 253046
43175 - 253053 - 253047
43176 - 253053 - 253047
43177 - 253054 - 253048
43178 - 253054 - 253048
43179 - 253055 - 253049
43180 - 253055 - 253049
43181 - 253056 - 253050
43182 - 253056 - 253050
43183 - 253057 - 253051
43184 - 253057 - 253051
43185 - 253058 - 253052
43186 - 253058 - 253052
43187 - 253059 - 253053
43188 - 253059 - 253053
43189 - Spare - 253054
43190 - Spare - 253054
43191 - 254033 - 253055
43192 - 254033 - 253055
43193 - 254034 - 253056
43194 - 254034 - 253056
43195 - 254035 - 253057
43196 - 254035 - 253057
43197 - 254036 - 253058
43198 - 254036 - 253058

 

[theblackwatch]

Further to post #88 by @43096 , 43189 & 43190 also had '253060' put on them at Crewe Works when they were painted - not sure if this was removed before they left though as I've never seen a picture of them out and about anywhere with it on them.

 

[Helvellyn]

A neat summary!

The delivery from 253041 onwards was re-jigged, so that the power cars for 253041 (43151/152) became the spares that 43189/190 had been intended as, and the extra 4 East Coast sets were prioritised for delivery and delivered as 5 sets (power cars 43153-162), with the NE-SW shuffled backwards. In effect, the original 253041 was eventually delivered as an extra East Coast set. I suspect that the swap-round of 43151/152 and 43189/190 as the spare power cars was to avoid giving 43151/152 to the Eastern Region, which would have left them with those two as oddballs by virtue of their GEC traction motors. What didn't help was that Crewe continued to outshop the power cars with their originally intended set numbers on the front hatch rather than in accordance with the revised delivery plan - a fact "theblackwatch" of this parish pointed out to me.

Thank you! I was doing it all off memory. As you say, having 43151/43152 as spare made sense but at what point did 43152 move to become an Eastern Region power car? (It was NL based by 1986 and named St. Peter's School York AD627)

95 sets and seven spare power cars gave one per HST depot in effect (LA, PM, OO, BN, NL, HT and EC). To compliment them seven spare TGS vehicles, 44095-44101, were also built and again were allocated one per depot.

I've dug out some old Platfom 5 books and the power car Lot No.s are:

• 43002-43055 Lot No. 30876 Derby 1976-77 (Dia. GB502 DMB)
• 43056-43123 Lot No. 30895 Derby 1977-79 (Dia. GB502 DMB)
• 43124-43152 Lot No. 30941 Derby 1979-81 (Dia. GB502 DMB)
• 43153-43190 Lot No. 30946 Derby 1980-81 (Dia. GB503 DM)
• 43191-43198 Lot No. 30968 Derby 1982 (Dia. GB503 DM)

The 1985 Platform 5 combined volume no longer shows power cars in the set formations but still lists the vehicles as being in sets numbered 2530xx or 2540xx. The 1989 Platform 5 combined volume is the first to include the power cars as locomotives within the locomotive section.

With regards Diagram numbers for the power cars I am assuming GB501 was used for the two prototype power cars when they became 43000/43001 as part of 252001?

Oh, as an aside the fact that 41001 became 43000 when it was reclassified as a Class 252 should show the intent that it had become a DEMU - locomotives are not numbered xx000, only coaching stock and multiple unit vehicles.