GWR 94xx Pannier Tanks, ex-Edward Thompson Thread.

It's an interesting thesis. I had a look at photos of a 1366 class to see how that was disposed (as the only other outside-cylinder pannier tank) but a cursory look at dimensions showed that that is a really very much smaller locomotive, particularly with smaller diameter and stroke to the cylinders, so the "packaging" considerations are very different.

Tom

 

Yes, the 1361/1366 are tiny (and loosely based on an 1873 design by F Trevithick* for the Cornwall mineral railway).

It occurs to me that maybe the reason for the Standard 10 on the 15s was the longer firebox made the balance a bit easier. I was just looking at a 1500 GA, and wondering why they were heavier than a 94 when my eyes settled on a massive structure between the cylinders , presumably there to stop them racking the frames to pieces.

*yes, a son of Richard Trevithick.

 

How do you explain the class 14s, 22s? (Another 114 engines)

WR had its own type 1,2,3 and two type 4s.

Is it really because of Midland region bias or because the hydraulics were more expensive and also their lack of ETH meant that they could not run with the latest coaching stock.

I can not help but think that the policies employed in the dieselisation of British Railways were perhaps the biggest disaster for the railways and destroyed the credibility of the railways with government to manage themselves. So much money wasted on poor designs, locos that were not needed etc etc. (But this is maybe for another thread)

But doesn't this take us back to the earlier point that the SR was right to focus on electrification - and in the end even its diesels were more successful than those on the WR

Shunters - success
Type 3 - success
71/74 - a failure by SR levels but as long lived as the WR hydraulics
73 - success
4xx - total success.

Modernisation and standardisation. (

Even measures like 33/1s were a cheap and efficient way of resolving a problem such as when electrification didn't extend west of Bournemouth for 20 years.

The only dogs dinner were the Exeter services until the 159s came along.

I think you could argue that going down the line of DEMUs was the biggest mistake and more DMUs would have done the job as well. I find it hard to argue that a 3H could do the job better than a 101, 108 or 117

Edited:

In the comparison of 0-6-0s perhaps a J72 ought to be added since the LNER/BR built a batch of them post-1945. I think it is significant that the LNER/BR didn't build batches of J50s but went for the J94s. While the LMS was already ahead of the curve with the precursors to the 08 so no need or interest in a new batch of Fowler 3Fs.

 

I'm just going to go with "I'm sure you are right", in all that you have said. Being a child of the 70's, the noisy blue boxes appalled me, and whilst I ended up regarding the HST very high, and cl66s sound oddly melodious in strange contrast to the work they are doing, I still don't like any of them.
I know, in my head, that electric traction is superior, that diesel-electric made economic sense etc, but my heart is unconvinced.

 

You’ve also conveniently forgotten that the Warships actually consisted of three different classes with different wheel arrangements, different engines and different transmissions so hardly a standard design. About the only thing they had in common was being named after Ships of the Royal Navy.

 

Class 74, or HB, were pretty dreadful. HA, or 71, were fine until their Dover to Hither Green traffic dried up. Noisy though, I once uncoupled the NRM example from a railtour at Southampton. It ran off with a roar that drowned out the 56 that replaced it.
Pat

 

The fallacy of electric v hydraulic rears its divisive head once again.

The Western Region acted on the BTC statement that all future freight trains would be braked hence the region adopted the lightweight hydraulic concept which offered the same power for half the weight (Class 42 = 78 tons for 2200 hp; Class 0 = 133 tons for 2000 hp). The BTC failure to actually follow that policy led to the "failure" of the WR's traction policy in adopting the hydraulic designs. A further consequence was that Beyer Peacock's hope of a further order for 200 Hymeks were dashed because the heavier Class 37s could handle the unfitted freights better hence the traction orders for South Wales Valley coal services.

A look at the WR policy shows a "standardisation" on Maybach engines BUT these were largely built by Bristol-Siddeley of Coventry who "changed" the specification without Maybach's knowledge and to the detriment of engine performance. The other policy "standard" of having 2 engines per loco was quickly abandoned by the designs preferred by the suppliers of diesel electric designs - apart from the Class 55 Deltic fleet whose success was gained by unit replacement at Doncaster whereas unit replacement at depot for transfer to Swindon for repair was deemed one of the factors that made maintenance costs too high in comparison with maintenance costs for diesel electric designs.

Even a close look at the Warship classes highlights the problems of "standardisation".

The North British D600 series was actually an hydraulic version of 10000 / 1 - built to the same specification but fitted with an hydraulic rather than electric transmission. The North British D8xx series was a poor copy of the Swindon product and was ordered at at time when it was hoped the order could keep the company afloat. It failed because poor workmanship / faulty metric measurement conversions to UK standards resulted in poor engine performance. In normal service the Class 43s were always considered inferior to the Class 42s hence the former were among the earliest withdrawals. Even the final Class 50 Warships were a botched "standard" being the development of DP2 with its 2750 hp engine a direct development of the 1600 hp engine fitted to 10000 / 1. It failed because BR insisted it have a flat front thereby forcing re-location of nose-mounted equipment, sought duplication of various accessories and addition of other equipment (e.g. slow-speed equipment) that turned the bread-and-butter efficiency of DP2 into the troublesome mix of technology that quickly gained a reputation for both unreliability and unpredictability in service. The fact that the preserved examples are so reliable is IMHO down to the removal of much of this extra equipment to return the locomotives to the same specification as DP2.

Reference was made to the Class 22 but this was also a trial design; its hydraulic transmission was built for comparison with the electric transmission of the Class 21 but the poor electrics of the latter combined with the engine problems of both classes quickly resulted in - initially - transfer of the Class 21 to Scotland and the subsequent re-engining of 20 but still retaining the problematic electrical equipment.

The final example of the Class 14 was designed as a replacement for the many Pannier designs; although I understand its bottom half was designed from the 94xx its top half was the "standard" centre-cab principle with the "standard" Paxman engine - albeit the 6 cylinder version IIRC of the engine later adopted for the HST.

In essence the WR tried to adopt a standard fleet but policy changes from above quickly prevented this whilst the "standard" policies of the individual regions (e.g. ER standardised on Class 30 / 31; MR (Midland) standardised on Sulzer; MR (Western) standardised on English Electric) conflicted with, rather than supported a national policy of standardisation. The nearest BR came to a "standard" locomotive was with the Class 08 diesel shunter and the Class 47 mixed traffic locomotive.

An interesting parallel is the electric traction fleet whereby the Class 86 was initially the sum of experiences from operating Classes 81 - 85 but the decision to change to axle-hung traction motors created a reliability problem that has dogged the various sub-groups throughout their lives. The Class 86 was improved to create firstly the Class 87 (with its reversion to frame-mounted traction motors) then the Class 90 (initially Class 87/2) to provide a line of development that has proved both reliable and obvious.

The irony is that diesel traction orders were encouraged by the availability of Government funding whilst the electric traction orders were delayed by the reduction of government funding in the Marples era when electrification schemes were suspended. Perhaps Marples' railway policies had a silver lining after all !

 

Another observation from Tom's comparison is that it considerably reinforces the proposition that the USA/S100 was in no way capable of doing the work that the 94s were designed to perform. Not only is it considerably less capable than the 94 design for trip work, its not even the equal of the 57xx for such services.

Can we also say that the more one looks at the detail, the less the 15xx looks inspired by the S100?

 

Is there any evidence of that, or is it one of those enthusiast myths? I'd have thought that if you take a steam locomotive chassis, remove the cylinders, remove the motion bracket, rearrange all the frame stretchers to suit machinery that will be in different positions and adjust the suspension for a loco of different weight and weight distribution, it's a bit tenuous to say the chassis of the diesel uses that designed for the 94xx! OK, it's got six wheels, two longitudinal frame plates and two buffer beams, and possibly used standard components for things like axle boxes, buffers, draw gear etc. but beyond that? You might as well say every class of inside cylinder 0-6-0 had a chassis design that was either "derived from" or "influential towards" the 94xx ...

Tom

 

But the S100s could have done the job of the 15xx no?

But lets go back to the question of need. Were the 94xx actually necessary to run the South Wales work? 210 locos with restricted RA for very specific jobs. By way of contrast - 110 Bulleid light pacifics, Q1s with wide RA. Was the need for the 94xx a critical need or was it something that could have been left for a few years and that the gap could have been filled with something else ie BR stds or transfers from elsewhere? That is a big investment for niche work with limited RA.

To echo the WW2 posters - is your engine really necessary?

 

There's only four ways to skin the cat of an 0-6-0 tank engine: inside or outside cylinders, and inside or outside valve gear. One of those wasn't (to my knowledge) used in the UK (though I think other countries had examples).

One of those - specifically, outside cylinders / outside valve gear - was relatively uncommon in the UK. So it is pretty inevitable that if two such designs emerge in close proximity, as in the S100 and 15xx, people will jump to the conclusion that one "inspired" the other. Whereas I suspect the answer is probably much more prosaic: the design office started thinking out the desirable features, and once you hit on "preparation without using a pit" you only have one avenue to go down. In other words, different design teams could quite easily arrive at very similar conclusions entirely independently if those conclusions are very obvious end points from the same or similar given starting points.

Tom

 

I suspect this is where you would need to look at what was scrapped at the same time as the 94xx was built. If you have 200-odd 40 year old 0-6-0PT locos near the end of life, then you need 200-odd locos of basically similar capability, but ideally more modern design, with which to replace them. (Or, in an ideal world, fewer such locos if you could guarantee higher availability from them) (*).

(*) That was, incidentally, exactly the argument for Leader: it didn't work, but the locos were designed to reduce a larger number of locos on account of better availability; but the fundamental requirement existed in the first place simply because those sleighted for withdrawal were by that time between 40 and 50 years old.

Tom

 

We've been through this before. A 94XX has three axles. A D95XX basically has four - three for the wheels, and a fourth for the drive shaft. There is absolutely no way they were derived from or inspired by. Different size wheels, different size wheelbase. Basically the only similarity is that the frames are made of metal.

It's a bit like the rumour that GT3 used a spare set of Std 5 frames. None of the published dimensions match. The wheel spacing is closer to that of a Manor than a Std 5.

 

I was just playing with that. A 15xx with the drive to the trailing wheels would have had a connecting rod some 13'6" feet long. The longest standard rod was on the 28s and 2cyl 4-6-0s at 10'8.5". Would that have been practical?
The 15xx valve gear has certainly been challenging to model engineers, perhaps not helped by the Speedy design being, shall we say sub optimal, but I don't think I've seen a serious criticism of the full size implementation. But I *think* I can start to see how some design factors interacted. It might have been nice to move the driving wheels forward to help with the front heaviness, but if they had done that there surely would have been no room for the motion. So they are stuck with the first two pairs of wheels where they are. The rearward ones could have come further forward to help with weight distribution and move the drive to the rear wheels, but if they had done that the wheelbase would have been very short, and the unsteadiness at speed even worse than it was. I'm definitely wondering whether the designers were forced into the short wheelbase rather than it being an original aim.

When I look at Tom's numbers it seems to me the S100 was closest to the 74xx (this was a very close relative of the preserved 64xx, but with a higher pressure boiler). It wouldn't have been anywhere near a 15xx. So unless the 15xx was very overboilered for the job then the answer is no. Its also instructive to look at some of the Welsh classes. The Rhymney S1 0-6-0T, for instance, used as a pure shunter, at 56T8Cwt, 1258 sqft heating surface and 23,870TE was a monster compared to the S100.

The RA does not seem to have been an issue in South Wales. And one should remember just how much of the GWR fleet was crammed into that small piece of geography. I've seen it said that everywhere was red route, and certainly the final designs of 0-6-2T on the Barry, Rhymney and Taff Vale were all red restricted. The pre group Welsh locomotives were all getting on and all scheduled for withdrawal. My opinion is that to replace many of the Welsh 0-6-2Ts - and at this stage only the newer and larger classes were left - the choice must have been between the 94s and building another lot of 56xx 0-6-2T. BR Standards don't come into it - when the 94s were ordered there was nothing on the horizon. So no, I don't think it could have been left for a few years, and I don't think a class of 210 can really be classified as niche. Were there that many of any of the BR Std tank engines?

 

Can we just pin that post somewhere to refer to every time the assertion is made, which is regularly …

I wonder if a lot of those kind of misapprehensions come from modelling, and particularly the 1970s to 1990s period with body kits made to fit on proprietary r-t-r chassis? You go from “white metal class 14 - fits Lima 94xx chassis” to, in fairly short order, “the class 14 had the same chassis design as the 94xx”.

Tom

 

I think you may be right there. But at least no one seems to suggest that an 08 has the same chassis as a Jinty!

Steve B

 

Well we had the question back a few pages ago about whether the SR needed 140 Bulleid pacifics so it is worth asking does the GWR really need 210 red route restricted 0-6-0s.

The point is that you hold on for a few more years with the older locos and then you build a bigger batch of BR stds. The Leader for example was a failure but it is hard to argue that the SR suffered because they had to wait a few more years till the Ivatts and BR standards arrived.

I find it hard to imagine that an S100 could not have handled ECS work in and out of Paddington. Paddington - Old Oak Common is hardly working stock out through Gasworks Tunnel.

 

IIRC the Bulleid Pacifics were built to replace a variety of 4-4-0 and 4-6-0 mixed traffic and passenger designs that were due for replacement by the beginning of WWII. Bulleid judged that the inefficiencies of working local trains capable of haulage by 4MT designs (note the number of 2-6-4T locomotives operated by BR on SR routes) would be offset by the high degree of standardisation from a modern fleet of Pacifics. That leads to the cost of making and storing the necessary spares which leads to the overall cost of running a locomotive fleet where the accounting world clashes with the operating world (i.e. total costs v operating costs and expense v income).

 

In respect of the Class 14 replacement I quote from The Diesel Impact on British Rail by R.M.Tufnell [ISBN 0 85298 438 3] where on Page 57 he states : The Class 14, known as Class D9500 when produced, was intended to be a replacement for the 0-6-0 tanks used for local freight and empty stock haulage, and it had been considered that a market existed for about 400 of this type. In fact the intention of the first 2 orders (for 56 locomotives in total) was to replace steam in the western reaches of the South Wales network west of Cardiff.

 

That doesn't say that the "bottom half was designed from the 94xx" as you stated though, does it?

Tom