Mark 4 Coach Compatibility

[cessna152towser]

As the Mark 4 coaches are progressively withdrawn from front line service, let's assume a few find their way into ownership of railtour operators or heritage railways.

Would these coaches be compatible to run with class 47 or 37/4?

Would the Mark 4s be compatible to run in the same train as Mark 2 and Mark 3 coaches?

[Simon Bendall]

The main issue is the couplings which within a set are a tightlock variant with the brake connections built into them. Only the TOE and the DVT have conventional drawgear (drophead buckeye, separate brake pipes) at the outer ends.

[jim.snowdon]

Apart from the coupler, I believe the gangways are wider than the standard, probably due in part to the need to accommodate wheelchair passengers. Adjacent carriages are also coupled via inter-car dampers, required to achieve the necessary ride quality at the full 225kph, and I would expect the auxiliaries to be single-phase AC only, making them incompatible with non-electric locomotives.

 

Some sets are understood to have gone to Transport for Wales, where they will be run as sets topped and tailed by a DVT and an outer end carriage.

 

[Wild Boar Fell]

2 hours ago, Simon Bendall said:

The main issue is the couplings which within a set are a tightlock variant with the brake connections built into them. Only the TOE and the DVT have conventional drawgear (drophead buckeye, separate brake pipes) at the outer ends.

 

The brake connections are not part of the tightlock (or Alliance) coupler. They have conventional pipes with gladhands.

 

Agree that the gangways would not be compatible. Electrically the vehicles would be incompatible due to the systems used on a Mk4. ETS wise you could connect to other LHCS.

[Ken.W]

Basically yes, Mk4s are compatible with conventional loco haulage, but only from the outer ends of the DVT and TOE vehicles.

Remember, the Thunderbirds were initially 47s and latterly 67s.

The Electric Train Supply's the standard BR system, though when being diesel-hauled the kitchen needed to be isolated to avoid overload. A 37/4 might manage ETS for a couple of these coaches!

 

The inner ends are a different matter however.

The couplers are a form of fixed head buckeye, though different to that on the HST, and not normally compatible with other stock. They do have conventional brake pipes though, not via the coupler.

The Mk4 gangway's also incompatible with other stock, besides being wider as mentioned above, there's also locating lugs and sockets in the faceplate and locking clamps on the sides of them.

The TOE, besides having conventional draw gear and buffers, has no gangway on the outer end.

 

There's no damper between vehicles,  There was one added between coach end and drawbar.

 

For railtours / heritage railway use, there's also the disadvantage of needing the DVT, carrying empty space around.

It would only work in push-pull mode with TDM fitted locos.

Putting a TOE either end of the set wouldn't work, as it's the DVT that controls the Door Interlock.

It's also the only vehicle with a parking brake when the loco's detached.

 

Ken

(Cl.91 driver, 1991 - 2019)

Edited May 26, 2022 by Ken.W

[Merfyn Jones]

They are in service with Transport for Wales using Class 67 locos and the DVT when propelling. Have been for a number of months now.  There are 3 sets for 2 diagrams on Holyhead - Cardiff route, coaches still in LNER livery.  A further 5 (I think) sets in Grand Central livery have been bought for future introduction on Manchester - Cardiff route.

[Ken.W]

11 hours ago, Merfyn Jones said:

A further 5 (I think) sets in Grand Central livery have been bought for future introduction on Manchester - Cardiff route.

 

Interesting, are they the ones that had been intended for the proposed Blackpool - Euston services, now aborted l believe?

[Steadfast]

4 hours ago, Ken.W said:

 

Interesting, are they the ones that had been intended for the proposed Blackpool - Euston services, now aborted l believe?

Yep, that's the ones.

 

Jo

[Adam1701D]

Providing you have a standard class end coach with buffers or a DVT at the end, the Mk4s can be hauled by any conventional loco, with or without ETH. Class 90 haulage on the ECML was common along with Class 47 and later 67 Thunderbird rescue locos. The end coaches are blanked off at the buffer end, so could couple to other marks of stock but through access would not be possible.

[JeremyC]

When it comes to heritage railways I would suspect they would rather avoid anything later than a Mk2b/2c, because beyond that you are into much more complicated sub systems, e.g. Air Conditioning.

[Wickham Green too]

.... and few heritage railways could operate air braked stock anyway.

[Ken.W]

On 02/06/2022 at 10:28, Captain Electra said:

Providing you have a standard class end coach with buffers or a DVT at the end, the Mk4s can be hauled by any conventional loco, with or without ETH. Class 90 haulage on the ECML was common along with Class 47 and later 67 Thunderbird rescue locos. The end coaches are blanked off at the buffer end, so could couple to other marks of stock but through access would not be possible.

 

 

Yes, that's the TOE (Tourist Open End) vehicle l referred to above, with conventional drawgear and no gangway at the outer end. I should perhaps add to what l said earlier about the Mk4 gangways being incompatible with other gangways that, the gangwayed end of Mk4s were actually prohibited from being coupled to any other types of gangwayed stock.

 

ETS isn't a problem, other than the high load of these, as l said they've the standard BR loco-hauled system, and although of course they can be hauled without it on, you certainly would not want anyone travelling in them in that case as there's no other form of ventilation. GNER even introduced portable door barriers on them so they could stand with doors open when stranded by power failures.

Plus after a short time without ETS the lighting goes down to emergency only, and when the batteries go down you've no door control and Interlock!

 

The class 90s were of course fully compatible* and worked in push-pull mode with them, not just loco hauled.

 

* Other than screw-coupled ones were prohibited from propelling around Carstairs curve.

 

On 02/06/2022 at 13:10, JeremyC said:

When it comes to heritage railways I would suspect they would rather avoid anything later than a Mk2b/2c, because beyond that you are into much more complicated sub systems, e.g. Air Conditioning.

 

Added to which, in this case, door control and Interlock operated by FDM, and retention toilets requiring specialist equipment to empty.

 

22 hours ago, Wickham Green too said:

.... and few heritage railways could operate air braked stock anyway.

 

Or operate ETH

[JeremyC]

Would retention toilets be that difficult a problem to deal with, wouldn't the equipment required be similar to the 'pump out' facilities provided at many boatyards on the canals?

 

On the subject of air brakes, can a steam loco fitted with the steam era Westinghouse brake work modern air brake stock or is the system totally different?

[Steven B]

There are plenty of steam locos fitted with air-brakes - Flying Scotsman, Clan Line, Tornado, Sir Nigel Gresley, Royal Scot and several Black Fives for example.

 

Air-con Mk2s aren't unknown in preservation circles, although they lack the flexibility of the dual brake/dual heat of the earlier types. There are several of the former Gatwick Express coaches preserved for example. There are still plenty pounding the mainline with the likes of West Coast Railways though.

 

As far as the Mk4 is concerned, it wouldn't be impossible to relocate door control and parking brake equipment from the DVT into a modified TSOE to make a TSOBE. The Electric train supply needs would restrict their use on preserved lines unless they were fitted with a generator. Probably far too much work for the vast majority of railways. There may be scope for train tour sets such as with the refurbished Blue Pullman HST and Intercity Mk3a sets.

 

Steven B.

[keefer]

There are plenty of support coaches (either Mk1 BG or Mk2/a/b Brake) with a generator set for use with 'heritage' trains - either steam (which won't have any ETH) or diesel (which may not have enough)

Certainly the easiest way of ensuring your rake of stock has adequate ETH and also provides accommodation for train/loco staff.

Would've thought that was easier than trying to chop & change safety critical eqpt in & out of different coaches.

 

[frobisher]

7 hours ago, keefer said:

There are plenty of support coaches (either Mk1 BG or Mk2/a/b Brake) with a generator set for use with 'heritage' trains - either steam (which won't have any ETH) or diesel (which may not have enough)

Certainly the easiest way of ensuring your rake of stock has adequate ETH and also provides accommodation for train/loco staff.

 

Though with the MK4's, the most expedient thing would be to modify the DVT to a generator van (the mods made to the MK3 ones would likely be a good template) eliminating two of its issues simultaneously rather than adding extra "dead space" onto the rake.

[roythebus1]

The Isle of Wight uses the Westinghouse air brake. Would the Mk4s fit on the ferry? :)

[hexagon789]

On 03/06/2022 at 19:54, JeremyC said:

On the subject of air brakes, can a steam loco fitted with the steam era Westinghouse brake work modern air brake stock or is the system totally different?

The modern system is UIC twin-pipe, this is fitted to all air-braked coaches Mk1 and later. It is backwards compatible in that you can operate it as single pipe if necessary or run twin-pipe vehicles with single pipe ones.

 

Given that air and dual-braked diesel and electric locomotives have worked twin-pipe passenger and freight stock and single-pipe freight stock with distributors without issue I would imagine that steam locos with traditional Westinghouse equipment would be able to do so, except the train would have to be worked as single pipe and the brake control would be graduated in application only.

[Covkid]

On 03/06/2022 at 19:54, JeremyC said:

Would retention toilets be that difficult a problem to deal with, wouldn't the equipment required be similar to the 'pump out' facilities provided at many boatyards on the canals?

 

On the subject of air brakes, can a steam loco fitted with the steam era Westinghouse brake work modern air brake stock or is the system totally different?

The majority of main line registered steam locos have air pumps to work on Network Rail metals. In fact there are only two operators which use vacuum brakes. Vintage trains' mixedcMk1/2 rake at Tyseley is vacuum braked and a proportion of WCR stock at Carnforth. Everything else is air or dual braked. The steam engineers have to be creative about siting the steam pumps and one of the Stanier pacifics has it in a plated recess on the back of the tender.

[pete_mcfarlane]

On 02/06/2022 at 10:28, Captain Electra said:

Providing you have a standard class end coach with buffers or a DVT at the end, the Mk4s can be hauled by any conventional loco, with or without ETH. Class 90 haulage on the ECML was common along with Class 47 and later 67 Thunderbird rescue locos. The end coaches are blanked off at the buffer end, so could couple to other marks of stock but through access would not be possible.

 I can add nothing to this debate, but the photo reminded me of watching class 91s through the little window in the end of the outer Mk4 coach. Not very often, as it was the smoking coach, so the train had to be a bit rammed before you'd risk going in there. 

[Adam1701D]

I remember that well. When GNER did the Mallard refurbishments, the rear half of the TSOE was still smoking, as well as half the end FO. There was a really heavy door separating the two halves and a very powerful smoke extractor system - the vents are still on these coaches today.

[Wickham Green too]

On 05/06/2022 at 22:53, Covkid said:

.... The steam engineers have to be creative about siting the steam pumps ....

Does the air pressure actually have to be created on the locomotive ? ..... with a two pipe system Id've thought they could fit an engine driven compressor in the vastness of the support coach and just fit the application valve on the loco.

[JeremyC]

34 minutes ago, Wickham Green too said:

Does the air pressure actually have to be created on the locomotive ? ..... with a two pipe system Id've thought they could fit an engine driven compressor in the vastness of the support coach and just fit the application valve on the loco.

The Leighton Buzzard Railway seems to use a system like you are suggesting. Of course what is acceptable for a light narrow gauge train might not be permissable on a larger one.

https://www.deviantart.com/rlkitterman/art/Isabel-in-PC-Allen-s-Train-at-Stonehenge-Works-752073542 

(The caption says "Isabel was built on the frame of a Motor Rail Simplex diesel locomotive to power air brakes on passenger trains pulled by locomotives lacking their own compressors.")

Edited June 6, 2022 by JeremyC

[5944]

13 hours ago, JeremyC said:

The Leighton Buzzard Railway seems to use a system like you are suggesting. Of course what is acceptable for a light narrow gauge train might not be permissable on a larger one.

https://www.deviantart.com/rlkitterman/art/Isabel-in-PC-Allen-s-Train-at-Stonehenge-Works-752073542 

(The caption says "Isabel was built on the frame of a Motor Rail Simplex diesel locomotive to power air brakes on passenger trains pulled by locomotives lacking their own compressors.")

For mainline locos, I believe the air compressor has to be on the loco. 35028 has it on the tender and I believe they've said if given the choice, they wouldn't put it there again. If the compressor is on the support coach, it would need to stay pretty much permanently attached to the loco.  

 

Amberley use (or certainly used to) a static compressor and recharge the air when the train stopped. But that's for a slow speed, short distance narrow gauge line.

[jim.snowdon]

17 hours ago, Wickham Green too said:

Does the air pressure actually have to be created on the locomotive ? ..... with a two pipe system Id've thought they could fit an engine driven compressor in the vastness of the support coach and just fit the application valve on the loco.

No, and what you propose is pretty much the way it works on a multiple unit.