Why keep HSTs?

[Glorious NSE]

Aren't some Mk4s supposed to be staying with East Coast though?

[Coryton]

Aren't the mkIV's longer than the mk III's?  This will lead to clearance issues on first radius curves  Having said that ISTR that when Grand Central started running short HST's there was an issue with braking capability.

 

 

If they are longer, it can't be much. They're all nominally 23 m coaches, aren't they? The IEP coaches are the first ones on National Rail significantly longer.

 

As for braking, I don't see it being a problem on the routes planned in Scotland - I don't think there's much scope for 125 mph running - after all they're replacing 170s. 

 

Aren't some Mk4s supposed to be staying with East Coast though?

 

Some, yes. And perhaps it would be handy to keep some of the others to cannibalise for spares?

['CHARD]

Aren't the mkIV's longer than the mk III's?  

 

Both nominal 23m vehicles.  

[Davexoc]

Mk.4 DVTs are only compatible with TDM fitted locomotives, of which no diesel locomotives are or were fitted.

Wasn't the TDM system originally developed for Scotland on diesel engines specifically for Glasgow-Edinburgh push-pull, class 47/7 shove-duffs? Done to replace the top and tail class 27s with dedicated Mk2 pressure ventilated stock.

Later rolled out on the electrics, classes 86 and 87.

 

Dave

[45125]

Wasn't the TDM system originally developed for Scotland on diesel engines specifically for Glasgow-Edinburgh push-pull, class 47/7 shove-duffs? Done to replace the top and tail class 27s with dedicated Mk2 pressure ventilated stock.

Later rolled out on the electrics, classes 86 and 87.

 

Dave

The shove duffs used FDM not TDM.

[D854_Tiger]

Only around half of GW HSTs are going to Scotland and only in 5 car formation.

 

This begs the question are there any plans for the remaining sets and the surplus mk3 coaches.

 

Wasn't it the long term ambition of Chiltern to convert all their Birmingham services to push pull operated mk3.

[Talltim]

Only around half of GW HSTs are going to Scotland and only in 5 car formation.

 

This begs the question are there any plans for the remaining sets and the surplus mk3 coaches.

 

Wasn't it the long term ambition of Chiltern to convert all their Birmingham services to push pull operated mk3.

I thought the long term ambition of Chiltern was to get rid of LHCS?

[frobisher]

I'm happy that this means there is life left in the HSTs, but it seems a shame to scrap the much never Mk 4s.

I'd guess that a few MK4 sets plus 91s might get picked up for other (open access) routes. Failing that, I'd place a bet on Bulgaria and Hungary nabbing a few.

[frobisher]

The Mk4's are fitted with tightlocks within set, so shunting/uncoupling/reforming etc. is no more difficult than with buckeye couplers.

They aren't at the standard height however so would require bespoke translators.

 

Ultimately, there's going to be a lot more MK3s available which are nowhere near as non-standard (relatively speaking) as the MK4s.

[russ p]

I thought they were standard height but the gangways are none standard and will only couple to themselves as they have locating lugs

[tamperman36]

A point that I believe many have overlooked is that by using an HST you get 2 diesel locomotives, one at each end as aposed to having one loco and a DVT, so should one power car fail the second power car could hopefully keep the train moving and thus keep the line open.

 

As for the MK3s fitted with powered doors. Didnt 442s have powered doors thus leading the way for the engineering and proving the it can be done. The MK3 has proved to be a very vesatile coach design with several conversions whereas MK4s have never really been given any major alterations so it would be a bigger job

[Coryton]

As for the MK3s fitted with powered doors. Didnt 442s have powered doors thus leading the way for the engineering and proving the it can be done. The MK3 has proved to be a very vesatile coach design with several conversions whereas MK4s have never really been given any major alterations so it would be a bigger job

 

More to the point it's already been done for Chiltern...and I believe it turned out to be harder than expected.

 

I'm not sure what alterations to Mk 4's you had in mind - they already have powered doors and CETs.

[Wheatley]

I thought they were standard height but the gangways are none standard and will only couple to themselves as they have locating lugs

They're a non-standard height, they are on what would have been the pivot point/axis on the tilting version of the Mk4. had they ever built any.

[royaloak]

Aren't the mkIV's longer than the mk III's?  This will lead to clearance issues on first radius curves  Having said that ISTR that when Grand Central started running short HST's there was an issue with braking capability.

 

Ed

2+5 is the shortest allowed for 125mph running, shorter formations are allowed but have speed restrictions due to the reduced brake force available.

[Coryton]

2+5 is the shortest allowed for 125mph running, shorter formations are allowed but have speed restrictions due to the reduced brake force available.

 

I don't think there's much 125 mph anyway running north of Edinburgh/Glasgow...

 

These trains are replacing 170s...

[Iankirby]

Only around half of GW HSTs are going to Scotland and only in 5 car formation.

 

This begs the question are there any plans for the remaining sets and the surplus mk3 coaches.

 

Wasn't it the long term ambition of Chiltern to convert all their Birmingham services to push pull operated mk3.

GWR are intending to keep some shortened sets for Cardiff - Taunton and Exeter/Plymouth - Penzance services although the exact number keeps changing.

[Titan]

They aren't at the standard height however so would require bespoke translators.

 

Ultimately, there's going to be a lot more MK3s available which are nowhere near as non-standard (relatively speaking) as the MK4s.

 

 

I thought they were standard height but the gangways are none standard and will only couple to themselves as they have locating lugs

 

 

They're a non-standard height, they are on what would have been the pivot point/axis on the tilting version of the Mk4. had they ever built any.

 

They are at a non standard height, but will couple to a standard buckeye. Not suitable for anything other than yard shunting due to the misalignment, which is why barrier (not translator) vehicles are required for main line use.

 

A translator vehicle is one which 'translates' the braking system  e.g. from dual pipe air to three step westcode. Usually they will need different couplings as well to haul the intended vehicles, but it is the translation of the braking system that makes them translator vehicles. The Mk4's will have air brakes so no translation required.

[pete_mcfarlane]

As for the MK3s fitted with powered doors. Didnt 442s have powered doors thus leading the way for the engineering and proving the it can be done. 

The CIE Mk3s were the first to have power operated doors. The design of the 442 was based on these. 

[phil-b259]

Unless the cost of changing the doors on the HST is zero, That will cost more than doing nothing with the Mk4 doors. Unless the cost of fitting retention tank toilets to the HST is zero, that will cost more than doing nothing to the Mk 4 toilets. As said, the trains will be fixed formation anyway so no coupler modifications required. As for wiring, if it really is that expensive/difficult just put a translator module in the TOE that converts the inputs from the loco to TDM. In that case only a small modification to the TOE is required, which would probably cost less than changing a door or two on a Mk3, no matter how cheap that is, with the rest of the train completely untouched. About the only point above which may be correct is spares availability.

 

The Mk4's are fitted with tightlocks within set, so shunting/uncoupling/reforming etc. is no more difficult than with buckeye couplers.

 

Thats all very well - but as has already been pointed out the Mk4 fleet is the LAST of the fleets to get displaced by the IEP / IET / whatever you want to call it. ScotRail want extra stock NOW!

 

Thus it doesn't mater how much cheaper / easier it might be to use MK4s over rebuilding MK3s - time simply doesn't permit such a thing being considered.

[royaloak]

GWR are intending to keep some shortened sets for Cardiff - Taunton and Exeter/Plymouth - Penzance services although the exact number keeps changing.

11 sets at the moment although GWR are trying to increase the number to 17 sets.

[Ken.W]

There's several problems with trying to re-form the Mk4 sets.

 

To start with, other vehicles / locos (inc the 91s) can only be coupled to the nose end of the DVT (fixed buffers, and drawhook / no coupling) or the outer end of the TOE vehicle (drophead buckeye, retractable buffers and no gangway). The intermediate ends / vehicles have fixed buckeyes, and besides hight issues discussed above with these, the Mk4 gangways can't be coupled to any other vehicles as they're wider than standard and also have locating lugs and side-clamps on the faceplates. So if reforming the sets, the only vehicles which can be at the outer ends are a DVT or TOE.

The DVTs are of little use on a shortened 5-car set, offering no passenger accommodation, and as already discussed, without major changes aren't compatible to work push-pull with any diesel locos.

Reform the sets with a TOE either end for Top and Tail working? Again major changes required as the DVT can't be left out of the set as it's this that controls the train door controls and actually operates the Door Interlock with the train brake. It's also the only coach in the set with a Parking Brake. Also, how many sets do Scotrail want, and would enough TOEs be available for this option? - EC plans on retaining six sets, and would probably want a couple of spares as the sets can't operate without one, so this would leave enough pairs for about ten sets plus spares. This option would also require a pair of modern diesels, expensive compared to a pair of redundant HST Power Cars, and with one being hauled around dead.

Also, without even more alterations, the Service Vehicle can't be left out, with it's full buffet and kitchen even in a 5-car set, as this contains the auto-announcer and controls the train PA system!

 

On the gauging question, it's not simply a matter of not having been passed for routes they're not required to work and there are differences between these and Mk3s. On the Durham Coast route for example, used for diversions, there's restrictions on Mk4s, but not for HSTs, such as speed though Heworth platforms.

 

The biggest issue with Mk4s though, as I've said previously, is their (lack of) reliability. In my previous comment that other operators suggested as recipients of them were prompt in saying 'no thanks' (or, more likely behind closed doors, 'you've gotta be joking'!), GEML was one of those I was referring to, and they have now ordered new stock instead.

 

Compare all this with the HSTs, change the doors and toilets, but full compatibility of any vehicles within the set, readily available Power Cars, no major reliability issues, and available sooner.

Finally, remember the Mk4s will be around 35 year old by the time they're replaced on EC, hardly to be considered as relatively new stock.

[pom-pom]

It is going to be a very sad day when the HST are withdrawn from front line services.

 

Terry

 

I agree, due to their longevity and success. However, I also recall feeling the same way about the class 44/45s being displaced off the Midland mainline services by the HSTs in the '80s... it was sad to see the last proper loco-hauled expresses disappear.

 

Nick

[Coryton]

I agree, due to their longevity and success. However, I also recall feeling the same way about the class 44/45s being displaced off the Midland mainline services by the HSTs in the '80s... it was sad to see the last proper loco-hauled expresses disappear.

 

Nick

 

Many years ago when a lot of people were mourning the end of the Deltics, resenting HSTs and saying that nobody would miss them when they were gone, I had a strong suspicion that when the time came for the HST's to bow out, they would be missed as much as the Deltics had been.

 

I think I was right.

 

Except perhaps they will be missed more. When the Deltics went, there were plenty of other loco hauled trains around with opening windows...

 

Given that we seem to be reaching a steady state now of multiple units with wholly underfloor equipment (be they electric or diesel) I wonder if there is much more scope for change. Some of us won't be around to see it, but I imagine that when the 800's finally give way to something new, it won't look all that different.

 

Then again fashions come and go and perhaps in 40 years a unit train will seem a wasteful use of power that does nothing overnight and we'll be back to locomotive hauled stock. Who knows?