Castle Class rebuilding in the 50s

@Jimc - did the GWR use a duplicate list for its numbering at any point in its history? It was a feature of at least LBSCR and LSWR practice (and I’m sure elsewhere) since, when a new loco replaced an old one as (in your terms) a renewal, the old one would generally be scrapped (or sold) and the new one simply take its number in the main list. If there was still useful life in the old loco, it would be added to a duplicate list and given some cypher or variation on the original number. The practice seemed to die out in the grouping era when continuity of numbers ceased and new locos started being numbered in new, continuous, number series.

I’ve often wondered if the disappearance of the process correlated with some modern development of information storage away from simple large ledger books.

Tom

 

..... and that's before you get round to the boilers .... even under Stanier. If they'd been LNER locos, any idea how many sub-classes there'd have been by the end of construction?

Thanks Jim. As I said in my 1st post in this thread, no expert on Swindon's practices me. Do you happen to know if 4073 received any updated nits'n'bobs during it's last trip through the works which it hadn't previously carried during it's working life? The 'prep' for preservation seems to have gone well beyond even what the Southern carried out on 'Gladstone' before it's handover to the SLS back in the late 1920's.

 

Talking of 4073 , if it were ready for condemnation in 1955, but not actually withdrawn until 63, what work was done, especially seeing 4074 (in the same boat) had a very through job done on it.

 

Yes. In the very early days 110 became 110A. I think this was dropped around 1866. Next they started numbering replacements from 1000, but in 1875 they introduced a system of allocating blocks of 100 or more for different types. The unique "second digit" scheme didn't come about until 1912. My own *guess* is that once the second and third generations of replacements came through and the lines started to plan maintenance (rather than just fix 'em when they broke) the use of duplicate lists and reusing numbers just got too clumsy. There was an Armstrong Goods, for example, that in its first 3 years of existence was successively numbered 428, 1066, 1090 and 38. This is all covered in my book: is it in the Bluebell shop [blatant plug!].

 

I don't know, but at that period its more likely to have been the opposite - that the locomotive would have been back-revved to an earlier configuration. She's got a 3,500 gallon tender now, and I believe no Castle had run with one of those since around 1930.

 

For what it’s worth, I had a chance some years ago to talk to Ernie Nutty of Swindon drawing Office fame, and he confirmed what I had heard from other sources who worked ‘inside’. Before 4073 when off to the museum it had an ‘every nut and bolt’ overhaul with everyone determined it would be as pristine and perfect as they could make it before it did so as a monument to ‘the old company’.

Which means that a retro fit to an old spec is a possibility - but if anyone who has a record of exactly what that might be has kept it to themselves.

 

Probably 842. Frames, boilers (fireboxes/throatplates/flues/top feed/dome), wheelbase, axleboxes, hornstays, piston rods, slidebars, brakes, valve gears, chimneys, lubrication, ashpans, for a start. The list is almost endless.

 

The LMS had a duplicate list, they added 20000 to the numbers of some ex Midland and and LNWR locos after the building of Stanier types had started. Any which remained at Nationalisation then got completely new numbers in a series starting at 58000

 

So does Caerphilly Castle have joggled or dished frames? Can anyone supply pictures to illustrate the difference.

 

It seems rather amusing that there was all this tinkering about with the numbers given to the standard gauge locos to suit the accountants. While on the broad gauge - just names.

 

Dean started turning out his 157 class singles as renewals, in the usual manner for that time... Except that, like Banquo's ghost, some of the supposedly dismantled original Gooch engines were still running round the system. So the newly built engines were indeed officially changed to being new construction.

 

I don't really have good drawings of my own that illustrate this satisfactorily. There are photos of models about, but none I found were quite as clear as I'd like.
Basically its about clearance for the bogie wheels. The wheels overlap the main frames, so straight frames all the way along would mean there would be insufficient sideways movement for the bogie. On the two cylinder locomotives this was worked round by truncating the main frames in front of the driving wheels and bolting on extensions, which were really bar frames - shallower and thicker. My guess is this wasn't an option if there was to be cylinders between them.
So on the Stars and the first Castles they effectively put a kink or S bend in the frames, viewed from above, so the frames were narrower at the bogie wheels.
On the later Castles what was done, by contrast, was to put an almost hemispherical dish in the frames only against where the wheels were, so that the majority of the frame was still straight.
The dish would seem to be a better solution to my uneducated eyes, but my guess is it requires some pretty awesome machinery to bend the metal, whereas the one dimensional bend of the joggle frames would be a little more straightforward.
I wonder if its something that could even be done with the machinery available now.

 

Search flickr for images of 7027 Thornbury Castle, several show the dishing quite clearly behind where the front bogie wheels would be. Images of 4073 at Didcot suggest it has a joggle. There are several Star images showing the joggle.

 

Ah, here's one where you can see the joggle on Pendennis...

You'd think there's be a photo showing a set of Castle frames from above, but I can't find one...




And here's the dish on Thornbury...

 

Thank you for the explanation/illustrations. I'd never noticed.

 

You forgot the post war ones had fluted coupling rods and the beading round the cab windows was flat not half round!! Little wonder that the Irwell Press Book of the Black 5s runs to five volumes