BR(S) DEMU could they have been developed further.

[KeithHC]

A couple of questions for the DEMU experts. The 2H when original built was based on the 2HAPs being built at the same at Eastleigh. As both types are basically similar could the DEMUs be built as dual mode. Could also the 6L and 6B have been built to restriction 4 and as Electro Diesel MU as further units for the western section. These units if possible could have been on the juice to Basingstoke for Salisbury and Exeter and to Bournemouth for Weymouth.

 

Keith

[JohnR]

It would have been interesting to see what the SR had planned for the East Devon branches. 

[frobisher]

As I understand it, there was a difference in the control systems between the EMUs and DEMUs which would come into play.  The two types couldn't work together so effectively isolating the two from each other would stop the problem occurring (because let's face it, if you could connect two MU types together, SR would do it).  So that might have pre-empted the obvious step of making the DEMUs bimode.

[Oldddudders]

New Haven had already successfully procured the FL9 electro-diesel, and Southern's own version wasn't many years away. Making the same configuration into a MU power car would have been feasible - but might not have left too much room for passenger accommodation. 

[25kV]

Given that control system interoperability existed between (say) 33s, 73s and EMU stock, it's probably not beyond the bounds of possibility that the SR could have made a bi-mode unit work, so it's perhaps that they just didn't need to... 

Now I'm leaping to the 1980s in my head and a bi-mode Class 210/455 design... :)

[30368]

On 26/06/2023 at 14:02, JohnR said:

It would have been interesting to see what the SR had planned for the East Devon branches. 

 

Sadly BR decided to handover West of Salisbury to the Western Region and memories are long lived on Britains Railways. I guess we are lucky that the former SR "Exeter Branch" survives. It is though nice to speculate.

 

As Ian mentions above, the SR DEMU's, whilst superior to the DMU's* of the day, were real rattlers and tended to shake themselves to bits as well as the 4SRKT engine and cooling system taking up a lot of space. If I recall 1129 had a high speed Dorman V12 fitted for testing. It was a small unit and would have given some additional space if pursued but it was staggeringly noisy. I know, I did a number of test runs on it and I'm sure my hearing suffered as a result. I don't think any of the control issues raised would have been unsurmountable. Unlike most BR Regions, the SR had its own Rolling Stock Development Department which was always looked on with suspicion by BRB M&EE Derby. I know, I worked there and it really was fun for a young engineer just out of his apprenticeship.

 

* Sorry Clive if you are watching....

 

Kind regards,

 

Richard B

Edited June 28, 2023 by 30368
Spelling!!!

[Wickham Green too]

Second generation BR(S) DEMU : - 

Carrickfergus 22/5/95

 

Third generation BR(S) DEMU : - 

Bangor : 15/5/89

[30851]

I think I read that they did consider bi-mode when designing the hasting units but the benefits were out-weighed by the extra costs so they didn't do it.

 

As for West of Salisbury I also think that the cancelled 3rd stage of the Kent Coast electrification was supposed to have released units from the Hastings and Oxted (and possibly others) lines for transfer to the west.

 

 

 

Rob

 

 

[johnofwessex]

Surely what would have been needed for further development was a better body, with power doors

[Wickham Green too]

I'm of a generation that knew how to open and close railway carriage doors .............. nowadays I stand in front of a pair of sliding doors  clearly marked 'AUTOMATIC DOORS' and expect them to open automatically ...... DUH !

[hexagon789]

5 hours ago, frobisher said:

As I understand it, there was a difference in the control systems between the EMUs and DEMUs which would come into play.  The two types couldn't work together so effectively isolating the two from each other would stop the problem occurring (because let's face it, if you could connect two MU types together, SR would do it).  So that might have pre-empted the obvious step of making the DEMUs bimode.

 

5 hours ago, 25kV said:

Given that control system interoperability existed between (say) 33s, 73s and EMU stock, it's probably not beyond the bounds of possibility that the SR could have made a bi-mode unit work, so it's perhaps that they just didn't need to... 

Now I'm leaping to the 1980s in my head and a bi-mode Class 210/455 design... :)

The prototype refurbished Hampshire unit 205101 (fitted with gangways etc during its refurb) had its control systems modified so that it could, in theory, multi with an EMU.

[Southernman46]

5 hours ago, 30368 said:

 

Unlike most BR Regions, the SR had its own Rolling Stock Development Department which was always looked on with suspicion by BRB M&EE Derby. I know, I worked their and it really was fun for a young engineer just out of his apprenticeship.

 

* Sorry Clive if you are watching....

 

Kind regards,

 

Richard B

Indeed, was fortunate enough to work there in the 2nd year of my BR Apprenticeship. I still possess the copy of the SR engineering drawing showing a 4-SUB retrofitted with a pantograph (I kid you not !) showing some of the thinking that was going on at the time

 

The Hastings Line units really were only a (typically ingenious SR) stop-gap between the Steam and full electrification which had been planned to carry on after the completion of the BOMO scheme, sadly due to the downturn in the industry during the late 60's & 70's, it never happened until 1986 and even then it required a number of technical developments to squeeze the scheme through on the cheap - all the while the RS department were valiantly preventing the DEMU's from rusting to pieces during the additional 18 years they operated ...................................

Edited June 26, 2023 by Southernman46
Memories

[bécasse]

I seem to recollect that there was some story that adding shoe gear to 6S/L/B units would have been foul of the Restriction 0 loading gauge and that was one of the reasons why the EDs had retractable shoe gear. However, it was a long time ago now!

[EddieK]

On 26/06/2023 at 20:13, hexagon789 said:

 

The prototype refurbished Hampshire unit 205101 (fitted with gangways etc during its refurb) had its control systems modified so that it could, in theory, multi with an EMU.

The prototype refurbished unit was originally unit 1111. As I recall, it could multiple with EMUs, some SR locos and also the mess room kettle.....

[Nearholmer]

On 26/06/2023 at 15:14, 30368 said:

I know, I worked their and it really was fun for a young engineer just out of his apprenticeship.

Was Alan Hall the man in charge? I’ve got a mental picture of the guy, but am not sure I’ve got his name right.

 

Honourable mention for this https://en.m.wikipedia.org/wiki/British_Rail_Class_210 , and of course, we all know that the HST was inspired by the stunningly rapid and near-silent acceleration of a train to Hastings clambering up out of Tonbridge.

 

More seriously, the DEMU concept, roughly in the form that it emerged on BR(S), goes back far into the history of diesel traction, and British firms had built versions for export. The GWR got close to building/buying some in the 1930s. The real Southern Railway’s traction plans as laid out in the couple of years prior to nationalisation included DEMUs for branch-lines, so the design teams had been mulling things over and drawing sketches for a good while before the chance to build any materialised.

 

Making a DEMU that would have had all the bi-mode capability and near-universal compatibility of an ED was definitely possible from the point that EP braking was adopted*, but the problem with DEMUs for a long time was the power-volume/weight ratio of engines and generators, which meant that they ate into potential paying space. It’s also the case that even now there’s not a clear-cut advantage for an electric transmission over the alternatives at the power levels needed  for distributed-power diesel passenger trains, unless/until multi mode capability, and/or the energy efficiency realisable by including energy stores for regen braking, or some other particular factor come into the equation.

Anyway, I’m jolly glad that I grew up in DEMU-land, because the BR(S) ones were light years ahead in terms of “passenger experience” when compared with those awful rasping, rattling, cloud-of-blue-exhaust-trailing abominations that infested other regions. Even in the power cars the ride was fairly good, and in the trailers there was no detectable difference from an EMU. IMO, the most cosy coaches on the SR were the first-class corridor trailers in some of the Hastings units ….. and the rate of progress allowed one to admire the glorious scenery of The Weald!

 

 

*In fact, thinking about it, probably even before that.

Edited June 28, 2023 by Nearholmer

[Nearholmer]

On 26/06/2023 at 14:02, JohnR said:

It would have been interesting to see what the SR had planned for the East Devon branches.

They explicitly stated in 1946/47 that they envisaged DEMUs for branch-lines in the west and for the odd branches east of the Bournemouth main-line where electrification couldn’t be achieved economically. I’ve often wondered which lines would have fallen into the latter bracket - very few, I think, given the Southern’s talent for ingeniously finding cheap ways to do things. Maybe single-line stragglers like the Cuckoo Line, but who knows?

[JohnR]

13 minutes ago, Nearholmer said:

They explicitly stated in 1946/47 that they envisaged DEMUs for branch-lines in the west and for the odd branches east of the Bournemouth main-line where electrification couldn’t be achieved economically. I’ve often wondered which lines would have fallen into the latter bracket - very few, I think, given the Southern’s talent for ingeniously finding cheap ways to do things. Maybe single-line stragglers like the Cuckoo Line, but who knows?

 

In the early 60s, the SR plan was for the East Devon branches to be converted to DEMU operation, and a depot was to be built in the 'v' of the junction at Exmouth Junction - on the opposite side of the main line from the Steam Sheds. 

[russ p]

On 26/06/2023 at 15:14, 30368 said:

 

Sadly BR decided to handover West of Salisbury to the Western Region and memories are long lived on Britains Railways. I guess we are lucky that the former SR "Exeter Branch" survives. It is though nice to speculate.

 

As Ian mentions above, the SR DEMU's, whilst superior to the DMU's* of the day, were real rattlers and tended to shake themselves to bits as well as the 4SRKT engine and cooling system taking up a lot of space. If I recall 1129 had a high speed Dorman V12 fitted for testing. It was a small unit and would have given some additional space if pursued but it was staggeringly noisy. I know, I did a number of test runs on it and I'm sure my hearing suffered as a result. I don't think any of the control issues raised would have been unsurmountable. Unlike most BR Regions, the SR had its own Rolling Stock Development Department which was always looked on with suspicion by BRB M&EE Derby. I know, I worked their and it really was fun for a young engineer just out of his apprenticeship.

 

* Sorry Clive if you are watching....

 

Kind regards,

 

Richard B

 

Hi Richard,  was this a later retro fit or one that was fitted from new. If that the same dorman V12 that's fitted to those big GEC 6w shunters it would have sounded fantastic you could hear those things for miles when they worked in Lackenby.  Sorry to hear it damaged your hearing. 

[Morello Cherry]

So here is a question, thinking about longer distance journeys and the modern use of 159s on the Exeter line.

 

Could they have designed a DEMU precursor using the CIG/BIG/TC/REP body work for Waterloo - Exeter and beyond.

 

Thinking about the 6L but rather than restricted width, Instead using the Mk1 body, buffet facilities for longer journeys. Ability to split at Salisbury.

 

A 6E?

 

Also, wasn't the 73 originally going to be a duel mode MLV? So presumably the equipment would have fitted in an MLV body MK1, so you might have lost a lot of the first carriage but you could still have had it have haulage capacity? Presumably the electric equipment would be able to go under the body as per the other SR electrics?

 

 

[BachelorBoy]

1 hour ago, Nearholmer said:

They explicitly stated in 1946/47 that they envisaged DEMUs for branch-lines in the west and for the odd branches east of the Bournemouth main-line where electrification couldn’t be achieved economically.

 

And then Riddles came along and screwed everything up....

[Nearholmer]

1 hour ago, Morello Cherry said:

Could they have designed a DEMU precursor using the CIG/BIG/TC/REP body work for Waterloo - Exeter and beyond.

I think you have to get into the mindset of the times, when Exeter and beyond was very firmly “long distance main line”, not even secondary main line, it was THE main line to the west so far as Waterloo was concerned, which meant relatively infrequent (except on peak summer Saturdays), heavy, locomotive hauled trains, and probably that would have remained the answer, as it did elsewhere until the 1970s.

 

For such long trips with heavy loads, it doesn’t make a whole lot of sense to spread the power down the train, especially if it prevents there being a corridor (there were serious dining facilities on the WoE expresses), and doing so simply multiplies the number of bits that can go wrong, as well as disrupting the established separation of maintenance facilities between engines and carriages.

 

The paradigm shift to full MU operation is vastly simpler with pure electric traction (no refuelling, very little maintenance, nice and clean) and the sort of high-intensity operation where stock doesn’t go ECS to a carriage depot between turns is a lot simpler to implement on relatively short hauls, with simpler catering facilities. Quick turnaround at Waterloo was increasingly used for loco-hauled Bournemouth trains, but even some of those were going ECS to Clapham Junction between trips right up to 1967.

 

If you look at how DEMUs were used on long-distance services elsewhere, various ‘streamliners’ in the USA in the 1930s, in Europe in the 1930s and again as TEE got cracking after WW2, Blue Pullman in this country, they tended to be lightweight, limited-capacity trains, power cars at the outer ends (one end only in the USA), providing s premium service, which is what the GWR looked at them for in the 1930s (IIRC for the Cheltenham Flyer). Those trains didn’t cover the ‘bread and butter’ heavy express diagrams. As power density grew, the ‘power car at each extremity’ trains could get faster and longer, taking us to the big changes that HST permitted, when infrequent 12 and 13 car trains were replaced by more frequent, faster, shorter trains.

 

I’ve often thought that where a continuing real Southern Railway might have got to was a sort of half-way house for the big WoE trains, using a 1600hp loco at each end of a train consisting of high-quality TC sets, maybe three four-car sets, some being what I will call 4-TR having catering facilities, and TLVs (big luggage, parcels and mail demand on long distance trains then). Using TC/TR would have made splits for Ifracombe, Plymouth etc very easy, EMU-like in fact.

 

In short, my instinct is that they could have created a WoE DEMU, it would have been more of the same but a bit comfier, and hopefully with a bit more power per car (The Green Pullman?) but probably they wouldn’t have, because in the context of the 1950s it was the wrong travel market for that sort of train.

 

As a footnote: Back in the mid 70s, I went on a couple of excursion trains to the WoE that used 33,TC, wired buffet,TC, 33, and that was a really nippy and flexible combo, with a higher hp/car than was typical of WoE trains via either the GWR or SR routes at the time.

 

 

Edited June 28, 2023 by Nearholmer

[Nearholmer]

12 minutes ago, BachelorBoy said:

And then Riddles came along and screwed everything up....

I think I’d blame capital starvation rather than one man …… the real-SR might, just have been able to raise the capital to see its plans through at reasonable pace, but in the context of a nationalised industry, other bits of which needed capital even more, in a country that was skint and trying to fund a few other things (the NHS, public house building, a huge schools-building programme, a probably oversized military, the muddled shutdown of an empire etc), it wasn’t going to happen.

[BachelorBoy]

1 hour ago, Nearholmer said:

I think I’d blame capital starvation rather than one man …… the real-SR might, just have been able to raise the capital to see its plans through at reasonable pace, but in the context of a nationalised industry, other bits of which needed capital even more, in a country that was skint and trying to fund a few other things (the NHS, public house building, a huge schools-building programme, a probably oversized military, the muddled shutdown of an empire etc), it wasn’t going to happen.

 

Northern Ireland was beyond Riddles reach ... hence its use of multiple units. 

 

[Nearholmer]

And coal was always more costly in Ireland, because most of it had to be shipped in.

 

The Enterprise remained a classic heavy, loco-hauled train into the 1970s and beyond though, didn’t it? In fact, thinking about it, it still was when I was last over there, which must have been about five years ago now. Ah, but thinking about it, maybe with a DVT.

 

 

 

 

Edited June 28, 2023 by Nearholmer

[BachelorBoy]

29 minutes ago, Nearholmer said:

And coal was always more costly in Ireland, because most of it had to be shipped in.

And presumably diesel was even more expensive because all of it had to be shipped in :-)