Rugby loco testing station

This fact was told to me by Chris Bailey when discussing his work with the restoration of D9531; he noted that the bottom half was based on the GWR 94xx 0-6-0 and the top half was a "modern diesel" design. Given that the Ribble Steam Railway's resident D9539 is owned by a member I suspect he has researched many sources to find out facts about his locomotive.

 

I am struggling with this idea.

The driving wheel diameters are clearly very different. At best, the position of the driving wheel centres could be similar or the same. Everything else is different.

Is there written documented evidence that can be pointed to for this, because on the face of it, it looks very absurd.

 

Looking at the side-by-side pictures posted by @S.A.C. Martin the immediate thing that strikes me is that the 94xx is a three axle design, whereas the Class 14 is a four axle design. That's a pretty fundamental stretch to suggest one is based on the other. The intermediate jack shaft then suggests to me that the wheel spacings aren't the same in the two classes. The depth of the frame plates looks much deeper on the class 14. A class 14 is longer than a 94xx.

Then - internally. On a steam loco, you start by positioning the cylinders and motion bracket to give rigidity to the front of the loco, and frame stretcher at the back under the cab and bunker, leaving a clear space for the firebox between the frames. Now, I'm no expert of diesel design, but I know they don't have a pair of cylinders in the same place, nor a motion bracket! I assume though that the general design process is the same - i.e. you make the frame a rigid structure with stretchers positioned to support the equipment it needs to support - it's just that the layout of that equipment is completely different, so the stretchers (and any holes, cutouts etc) will need to be positioned differently.

Maybe some small details might be similar? Well, the wheels are clearly different, as are the coupling rods. The brake blocks are in front of each set of wheels on the 94xx, but behind the leading wheels on the class 14, so there must be some fairly significant differences in the brake layout. Buffers? They look different.

Where exactly is the similarity that makes it plausible that "the bottom half was based on the GWR 94xx 0-6-0"?

Tom

 

If there's documented evidence that shows there to be a real, tangible link to the 94xx, I'm prepared to be humbled! But on the face of it, I can't see how you arrive at the diesel from the steam loco other than starting with an 0-6-0 wheelbase arrangement. On the face of it, it seems apocryphal to me.

 

But are there different perspectives for this? Now I have exactly no actual information on the subject, this is all guessing. However it seems to me that stretching or shrinking wheelbase, maybe even adding the extra axle, aren't very significant factors on the drawing board. Crucial of course if you want to exchange parts. **If** the arrangement of the suspension is the same, the axlebox components, all that detail, is there a case to be made? Mind you that begs the question, how different could it be? It is, after all, a 6 wheeled locomotive chassis in which the drive is transferred between wheels by coupling rods.

The 94xx chassis and its components, for all it was very much developed from all those that went before, was probably in detail design pretty much what Swindon Drawing Office considered to be best practice in 1946. How much had the state of the art in those sorts of chassis components advanced in the meantime? Wouldn't you expect the drawing office staff, trained from their apprenticeships twenty years before to reuse standard components whenever possible, to do exactly that? If you imagine the same suspension components, same bearings etc, then that's a great many parts you can just trace onto new drawings with the different spacings rather than design each component from blank paper. I have no idea whether that sort of thing went on, but it doesn't seem beyond the bounds of possibility that it might have. If you think how many drawings must make up the chassis for a locomotive like this, I bet relatively few of them actually include the wheel spacing.

It seems to me that if you can save even 20% of the design work by using existing components or even tracing significant parts of those components without compromising the design then that's a useful saving. How much reuse of existing drawings counts as "based on", well that's a hard thing to define... But if you were a draughtsman in Swindon drawing office working on the chassis design for the new 0-6-0 diesel, why wouldn't you have the drawings for the last 0-6-0 steam on the table beside you to see what you could reuse?

 

It may stem from the LMS diesel shunter 1831,which was based on the wheels and frames of an ex Midland 0-6-0 tank. It kept the same number as it was regarded as a rebuild, although a drastic one!

 

Sorry, but IMO the only thing that the 94xx and Cl.14 have in common (apart from being 0-6-0's) is the work for which they were designed - shunting and tripping - and much of that had disappeared by the time the latter were built.
Ray.

 

“The bottom half”

I think it’s the “bottom half” of the wheels…and only when the weights are at the top…

 

Hughes, the author of the paper who was I believe also the leader of the GT3 project, does not spend a lot of time on this point but makes the comment "The intention behind the frame design was to give a stiff unit free of weakeness.." but the frames must have been a useful source of weight. The adhesive weight on the driving wheels was 65tons which with a starting tractive effort of 36,000lbs gave a factor of adhesion of 4.0. It appears that production locos would have been a bit lighter with a factor of adhesion of 3.7.

 

AIUI E2001 was used as a mobile load bank for testing and commissioning of the overhead lines as the electrification work progressed. I remember it in the sidings outside the testing station in the late '60s; there was a lane alongside the DED from which a metal gate gave access to the drive up to the testing station. The sidings were on the opposite side of the drive to the gate, E2001 was parked about a third of the way up and there never seemed to be anyone about. One day my mate and I decided we'd climb over the gate and get a photo with my old Brownie 127 camera, but some bloke came down the drive in a car and caught us. He demanded, quite sternly, to know what we were doing. When we told him his attitude softened, he told us to be quick and to make sure the gate was properly closed when we'd done. He then drove down to the gate, got out of his car opened the gate and drove away leaving us to close it for him.

 

The only thing the 94XX and the Cl.14's have in common is the gauge and the vacuum pipes. Even the couplings are different. Oh, and the corks in the coupling rods. Anyone who thinks otherwise is dreaming.

 

Now this is interesting - this is a true "rebuild of a steam loco to a diesel form". https://topstastic.blogspot.com/2021/07/lms-1831.html

Diesel hydraulic, only ran for about seven years. Paxman engine, interestingly (the company of HST Valenta fame).

Quite an impressive conversion, really. The wheels, frames, running plate and buffers/bufferbeam have clearly come from the steam loco but little else has I would suggest.

 

I wonder what they did with the cylinders - left them in situ for bracing and weight purposes, or took them out and put in new stretchers?

Anyway - while on this diversion about weird conversions of traction, here's another: No. 56273 from the first series of what later became the well-known SR "Queen Mary" brake vans. The first ones were rebuilds on the under frames of the LBSCR overhead electric Motor Luggage Vans, which had been made redundant by the conversion of the short-lived LBSCR overhead electric to LSWR-pattern third rail at the end of the 1920s.

(The MLVs were interesting vehicles, generally sitting in the middle of a five coach set with a trailer and driving trailer vehicle at each end.





Tom

 

I nominate this thread for a prize for greatest thread drift.

 

Davey Paxman in those days of course, perhaps better known to enthusiasts for supplying steam locos to the Ratty and RHDR. I think the hydraulic transmission is worth further study. From a description in the Locomotive (where it is described inter alia as a "hydraulic generator"), the diesel engine was used to pump fluid to a "transmitter", which I suspect is describing something different to a co-axial torque converter which became the standard form.

 

Have always felt it was a shame the testing station was knocked down I think in the 80's. My memory may be incorrect but I think where it was is still unused land.

 

I well remember my friend suggesting that we cycle to Rugby to "see the trains" and we ended up where the GC line went across the main line and the testing plant was just in sight. What I hadn't realised was how far Rugby was from our home in Leicester! This was around 1963.