JimC

Which in turn got be thinking about 0-6-0Ts and 0-6-0s on the GWR. The 57xx and the 2251s had slide valves with this layout when built in the 30s, but piston valves had been tried on the 2796 and some of the 2779 lots of 2721 class pannier tank before about 1920. According to RCTS they had exactly the same valve gear as the Stephenson's fitted locomotives, but had the valves on the centre line, one above and one below the cylinders. The steam passages must have looked like a nest of snakes! RCTS says that the valve rods carried arms which provided the offset to the valve spindles. I'm not sure I altogether understand that, whether they were jointed or rigid, but it must have looked rather peculiar. Bet you never realised your Hornby model might have had something so unconventional hidden inside! And this in turn got me thinking about inside cylinders and 0-6-0s and why they survived so long. If you have inside cylinders for the lack of rocking couple and its presumed effect on the track, (I wonder if outside cylinders tended to make already dodgy track worse - that could be a consideration for industrials perhaps?). Why not put valve gear outside to make things easier. But then I wondered, if you did that might some drivers be a bit lazy about big end oil boxes? Dean tried external Stephensons valve gear, internal cylinders on one of his more outre experiments, but it would look bizarre on an inside cylinder locomotive. Do I feel another sketch coming on? [Later] - looked at external valves and gear on a 94 and it doesn't work. Wheels just as much in the way as they would be for outside cylinders.

Yeah, grafting the 4-4-0 layout of the leading wheels being driven onto a 4-6-0 chassis is problematic. However laying things out to drive the middle wheels requires more design expertise than I possess. I'm not uncomfortable with having plenty of smokebox behind the saddle - think 4700 in Std 1 boiler form or the Bulldogs with Std 3 boilers, but a forward extension of the smokebox might well have been necessary, it's a good thought. Valves on the City/Aberdare/Duke series are *under* the cylinders, in what's called the Stroudley arrangement, which leads to rather convoluted and long steam passages but does help with space. It also gives direct drive to both valves and cylinders, rather than indirect via rocker as in the Churchward Standards. The cylinders and valves are not on the same axis, the valves are level in line with driving axle, the cylinders inclined 6 degrees. Now I think of it, I idly wonder if this inspired Holcroft when he pointed out to Gresley that valve and cylinder didn't need to be on the same axis with the centre cylinder of his conjugated gear. Another thought from writing this is that Stephenson valve gear layout is best with direct drive - valve rod aligned with wheel axle, but Walschaerts doesn't require this. Hence it seems to me that slide valves between cylinders is an ideal layout for Stephensons, but with large piston valves and cylinders I guess it's easier to get a good layout with Walschaerts. The Churchward outside cylinder classes have the complication of rockers to align everything correctly, whilst the 4 cylinders take advantage of the intrinsic properties of Walschaerts (and the scissors gear on 40 was really a Modified Walschaerts) to fit everything in. Cylinders saddle and chimney are typically vertically aligned on GW 2 cylinder classes and I wanted to follow that pattern, thus cylinders between bogie wheels. On reflection I probably should have paid more attention to the layout of the cylinders on the Stars, rather than looking solely at the City for the workings, but the inspiration was the Dapol kitbash. Also the further I go from the Swindon draughtsmen's work the more likely it is that my lack of knowledge and training will result in something ludicrous that could not work, which is a problem for me if not for the topic! Very good thought provoking post, I fear I've just edited it into a long essay, got me thinking about a number of design issues I hadn't considered before. I hope my guessing/interpretation is reasonable, and I'm not coming up with false speculation.

I had a bit more of a play with the inside cylinder Saint, and drew up the valve gear and cylinders. That was all very well, but that made me realise the front bogie was in the wrong place re the cylinders, so I had to extend at the front (and move the chimney on the smoke box) . Then I realised the brake cylinder was all tangled up in the motion and I had to change the brake setup round , and it started getting difficult. Still not sure that will work. I also gave it a short cone boiler and removed the top feed to make it look more Edwardian. I'm really surprised by how much that changed the appearance. Just for a bit more amusement, here's a wire frame of the drawing. Basically the cylinders, motion and (steam) reversing gear are from the City Class, so the valves are under the cylinders, Stroudley style. The drawing I had seems to be for the as built condition with slide valves. Presumably piston valves would have come later. The performance would doubtless have been rather second rate compared to a real Saint.

Perhaps get the first two driving wheels as close together as possible and aim for something like an inside cylinder Saint?

In RCTS (pC24) they mention No 245 having had at different times a Swindon boiler put on at Wolverhampton, and a Wolverhampton boiler put on at Swindon. I suppose one might imagine a Swindon boiler swapped off a locomotive at Wolverhampton, repaired, and put on the next repair, but I get the impression that in the 19thC boilers were not swapped regularly in the way they were after Churchward. A train of various boilers being taken from one factory to the other would be something different for modellers! More likely, I suppose, that they would go one at a time on normal service trains, but its a fun thought.

I think a desire to standardise parts was widespread. Gooch rejecting locomotives that didn't come up to specification is a often noted early example, and there are lots of examples of 19thC Locomotive Superintendants attempting to standardise parts across two or three new classes. I think the credit due to Churchward is not that he founded the concept, but that he was the best at it, and by commitment and vision did a far better job than anyone else. Another part that we perhaps tend to overlook is how important competent management was. Railway workshops - perhaps all workshops - had a definite tendency to revert to doing one job at a time with little regard to the big picture when it seemed convenient. Perhaps Churchward's biggest achievement was not that he introduced a number of classes with standardised parts, but that the (G)WR was still operating to those principles thirty years after he retired. I don't have too many non GWR books - only so many bookshelves even in a house where we have thousands of books, but one is Cox' 'Chronicles of Steam'. Around p48 Cox is talking about standard boilers, and reading between the lines some of us may judge that the LMS draughtsmen pushed back mightily on Stanier's ideas to refit LMS locomotives with a range of standard boilers by claiming it was just too difficult and not worth it. We might note their contemporaries at Swindon managed, but doubtless Stanier judged which battles were worth winning. ----------------- Incidentally, am now going through RCTS trying to produce a rational list of pre Armstrong 0-6-0s. Damn its going to be a struggle. Did I mention management - locomotive policy in the early days was (predictably I suppose - it was early days) chaotic and loans, rebuilds, renewals, reconstructions, make it a very challenging task. Makes me recall why I tended to fight shy of that era in the book, and also increases my admiration for the RCTS author(s) who had to try and make some kind of order out of what must have been a spectacular mess of source documents from all over the place. In the past I've wished the author of RCTS Part three had used a more tabular and less narrative style describing classes, but I'm starting to realise that, especially in a pre word processing age, doing so would have been an almost insufferable burden. What a filing system he must have had to create!

Something that's struck me today, looking at these and trying to find pictures of them in their later careers - can anyone help - is what an incredible rag-bag of 0-6-0 freight engines the early GWR possessed. I haven't looked at numbers, but there seem to be many more than I imagines, quite outnumbering the GWR constructed early 0-6-0s. They were pretty much all rebuilt or renewed at Wolverhampton, tending too merge towards a common style, especially with GWR boilers fitted, but all different, all different. No wonder that Armstrong's class were called Standard Goods: there was so many that were anything but. I imagine the same is true of 2-4-0s and 2-2-2s, although I haven't really explored, but the 0-6-0s really struck me today.

This seems OK now. Have you changed something (if so well done) or is it a side effect of the site running in basic mode?

I've been trying to sketch out an express Atlantic based on the GWRs notorious Krugers, but I just couldn't make it work. The grate on the Kruger is quite long even though its a wide box, and the whole thing was out of balance. I got this far before I gave it up as a bad loss... You'll notice that various vital components are missing which I hadn't got to before I gave up. Thought I'd post the part complete anyway to provide, hopefully, a smile in times that need them... One thing for sure, if anything its got even uglier!

Found an illustration of the 2-4-0 :-). This is from the same article in the Engineer as the image I linked to earlier. There's also some discussion and more images on this thread:

I've had a first stab at the locomotives in original condition, which I've added at the top. For the vexed question of livery, I've seen mention of dark reddish-brown, and that's my idea of a dark reddish brown. As is my convention I've left off lining. I'm being naughty by giving it the number 1 - it seems that four of the locomotives carried names, but probably not their numbers, while those that were nameless displayed the numbers. No 1in the stock list was the mis-spelt Treffrey. Coal - well maybe @MarcD can tell us from the GA drawing. I note, however the diagonal line of rivets towards the back of the tanks, which looks like a watertight partition. I'll speculate, on no more evidence than those rivets, that possibly there might have been a coal supply there. The eventual Lynne & Fakenham/Eastern & Midland/M&GNJR version of the locomotives as 2-4-0s with larger driving wheels would be an interesting addition to the page, but rather off my theme. But does anyone have a photo they could upload? There's a photo of one as an 0-6-0 tender locomotive here. https://rogerfarnworth.com/2019/11/16/the-lynn-and-fakenham-railway-part-1/ Interesting to note that at this stage it still retains the side tanks, complete with the original CMR number plate, but has acquired a reasonable cab.

That would be interesting and useful to see. Would you be able to share it with me or let me know the source?

https://www.vintagedition.com/1890-cornwall-mineral-railway-1873-locomotive-metamorphosis This is from an article in "The Engineer" about the other members of the class that were rebuilt as 2-4-0 tender engines somewhere well to the east of Swindon, but the drawing is very helpful. I tend to be suspicious of drawings (and models) as sources, on the grounds that the artist may well not have been any better informed than I am, but that one clarifies a number of smudges I was unsure of in the photo and seems well founded. I was also delighted to spot in the text a dimension for the footplate height, which is rarely documented on the weight diagrams but enormously helpful for getting proportions correct. The buffers appear to be conventional but short, which is also the case in some other small locomotives of the period I have sketched. Supposedly as pairs they were single manned, and you can see how the cab steps would make transfer between the cabs on the run possible, but surely rather perilous even for 19thC concepts of safety. You'd think a gate in the rear cab sheet would have been far more practical. Maybe though, if they were used in pairs, they tended to run with the driver in one cab and fireman in the other. Also one imagines that speeds on a 19thC mineral railway would have been very low, even compared to the conventional 25mph of unfitted freight on the main line.

According to RCTS a lot of them lived at Swindon. Here's a thing. I'm just looking at sketching up the as built configuration as per this very useful photo. RCTS states that the frames were lengthened at the back to fit in the bunker, but when I line up this photo with my drawing it seems as if in fact they didn't. Instead the cab entrance was moved forward. At least I'm finding that the cab spectacle plates and wheels only line up with the photo if you assume they didn't extend it. What does the panel think? And another curiosity- the locomotive is assumed to have been named after Joseph Treffry, a major local land owner and entrepreneur who had built several horse drawn tramways that became parts of the Cornwall Mineral Railway. But if so they spelt his name wrong!

I do wonder how much coal they spilled coaling these from a standard GWR stage. There were special carts for smaller bunkers as below at Didcot, but even so it must have required some precision. The glazing on that rear mounted spectacle plate must have been awfully vulnerable too.

For interest, these are the two images I made most use of for this sketch. The numbers shown with 1392 present and 1398 absent presumably date the diagram to between April 1883, when 1398 was sold, and November 1906, when 1392 was withdrawn. My best guess is that the weight diagram is the condition after they were converted to saddle tanks in 1883/4, and the photograph is possibly after the first boiler change which was Jan 1904 for 1396, but it could be any time up to March 1934, by which time it would presumably have had a 1361 boiler (RCTS doesn't mention dates for that change).

An interesting class, not least because they were significant as being the basis of the design of the 1361 and 1366 classes. In their original form the locomotives did not look much like this, being side tanks with no back to the cab and intended to be used in pairs operated by a single crew. They were built by Sharp Stewart for the Cornwall Minerals Railway. The designer is a little obscure. Its apparently credited to an F. Trevithick. Francis Trevithick, son of the great pioneer, had formerly been Locomotive superintendent of the Northern division of the LNWR and was resident in Cornwall at the time working as Factor for the Tehidy Estate, which had considerable mineral connections. One of his subordinates had been Alexander Allan, inventor of the eponymous valve gear, with which these locomotives were fitted. There were other F. Trevithicks, but he seems to be considered most likely. The GWR took over running the line in 1877, but only acquired nine of the line’s eighteen identical locomotives as the other nine were pledged as security against various debts and were sold separately. The GWR numbered their locos 1392-1400. In 1883/4 they were all converted to saddle tanks and given a rear frame extension to provide a conventional cab and bunker. They received a variety of cabs, tanks and bunkers over the years and were twice reboilered, the second time with 1361 class boilers, but were otherwise little altered. One was sold in 1883 and 1392 scrapped after a collision in 1906, but otherwise they survived into the 1930s. After 1392 was scrapped the class became known as the 1393 class! At the 1912 renumbering 1400 was renumbered 1398, being the number of the loco sold in 1883. In GWR history they were significant as being the basis of the design of the 1361 and 1366 classes. Harry Holcroft tells the story of "a roll of musty old drawings" being deposited at his drawing board, which were those of the 1392s, which he was instructed to use to design a complete new class. This sketch is partly based on a 19thC weight diagram which is minimal in the extreme, and partly on 20thC photographs. I think its hopefully reasonably representative of an 20thC configuration for the class, although I've had to rely a little more on the known similarity to the 1361 class as is perhaps advisable. Later weight diagrams exist and it would be interesting to see those to try and tie things down a little more.

Oh yes. if you want to get an idea of the variety of subclasses of boilers take a look at the end of my GW standard boilers web page here: https://www.devboats.co.uk/gwdrawings/gwrstandardboilers.php#prefix I was lucky enough to have sight of a couple of GWR documents which listed boiler prefixes - as the GWR called the two letter code - and combined the information and published it there. Its not a complete list, because some types were extinct by the time of the documents.

Perhaps overstated for the GWR. If there was a significant operational or maintenance advantage then they would most definitely retrofit. Perhaps the most obvious example is the rate at which Churchward had superheaters fitted to the existing fleet. I believe that by WW1 the GWR had more superheated locomotives than all the other lines in Britain combined. And fitting superheaters is not a minor change as the whole tube layout is different with the flue tubes. Presumably with top feed the advantages weren't so marked on the small tank engines as it was on the taper boilers where it seems to have been retrofitted quite swiftly. I don't believe the Frenchmen had top feed. I think you'll find the arrangement that looks superficially like top feed is in fact external steam pipes. I think it depends on your background. The key point to the GWR seems to have been interchangeability. They certainly didn't let standardisation preclude necessary improvements: indeed you could make a case that continuous improovement - to some extent anyway - was GWR policy. An example is in tenders, where one can see a mix and match approach where later design parts would certainly be installed if necessary/desirable. With boilers its important to be aware that there were sub classes, and with the most numerous types there were quite a number which weren't strictly interchangeable with different fittings for tank and tender engines and the like. I don't think, for example, that 2721s ever carried the 200psi boilers with two flue tubes used on 57xx. The number of P class boilers was large enough that they didn't need to be pooled between the pre group and Collett classes with P class boilers

The other problem with this on my 1920x1200 Huawei tablet is that the downward creeping banner hides the notifications, so I have to tap repeatedly and quickly to grab them before they are hidden. If I'm too slow only thing to do is hit refresh and try again. This obviously does not help site performance one little bit. Also at the moment I am largely typing blind since blank top ad, video and on screen keyboard cover about 85% of the screen. I refuse to use ad blockers for moral reasons, but this is not a user friendly experience... NB Its only an issue on the tablet, its usable on 720 x 1280 phone and on PC.

GWR Goods wagons has dimensioned weight diagrams for similar types which should help. Unfortunately b/w scans so dimensions are difficult to read. O39 17'01/4 inside body, 8'0 body width, 8'7 over ironmongery, 7'3 height off rail, 3'51/4 solebar to top of body. Anotated 040/042 same except brakes and W iron type. V36/7 were 20'6 over buffers, 17'6 over headstocks, 5'0 and a fraction door entry clear, 11'81/4 total height, 6'0 9/16 door entry height clear. Both 10' wheelbase.

A number of classes were given rear frame extensions for more coal and water capacity and the bunker could also go higher, so maybe those changes were made after a bit of experience with the prototype?

Perhaps I can be of assistance? Does this help? And for non-fictional GWR 4-6-0s may I recommend the link in my signature?

The current "going Loco" blog at Didcot features Pendennis Castle's record card. https://didcotrailwaycentre.org.uk/product.php/78/going-loco. To my surprise she appears to have twice been fitted with the relatively rare flush tank (=Collett) 3,500 gallon tenders in the 1930s after having had 4,000 gallon tenders.

I'm not sure there's a good answer to that request. There was a feature in the Great Western Study Group Magazine Pannier, issues 17 and 18, which isn't bad, and the GWSG will supply reprints. There's some information in RCTS part 12 which is only available on the second hand book market, but I don't think its one of their best pieces. There are illustrations at the end of the Russell books, also only on the second hand market, but no significant written content. There's a chapter in my book, but its only seven pages and I could do better now as I've had sight of some significant archive material since then. There's probably a book's worth of material if one were to cover the subject in good detail, but how many people would buy a book on GWR tenders? I can't imagine the author making enough to cover the cost of some reasonably thorough research. Even though I say it, the web page I wrote the shell of and @Miss Prismhas considerably expanded at http://www.gwr.org.uk/no-tenders.html is probably not the worst piece on the subject.