Pannier Tanks

Yes but... I'm not sure you're looking at that the right way. To my mind you first need to separate the large and small types, which had entirely different lineages (and route availability), and then look at boiler choices from the kit of parts.

Starting with the large types, and all these were designed and built at Swindon.
1813 (eventually), 1854, 1701, 2721 and 5700 had 7'3" - 8'3" wheel spacing, and P Class boilers with the flat grate between the wheels. Arguably they could all be described as a sort of super class.
When you come to the 9400, it was roughly speaking a lengthened 5700 chassis with the same wheel spacing (7'3" - 8'3" wheel spacing) and they were using an existing boiler originally designed for absorbed classes, not a new design. This was the standard 10, and already had a sloping grate and a rather longer firebox than the P class. The sloping grate enabled the longer box to fit over the rear wheels without having to change other components (other than suspension arrangements). If you consider the kit of parts available at the time the Std 10 (already used on the 2251) was the only existing boiler really suitable for a heavier 0-6-0T.

Now the small types, and the pre group ones were built at Wolverhampton and I very strongly suspect designed at the Wolverhampton drawing office.
850 and 1901 had 7'4" - 6'4" wheel spacing, and pre group 2021 and post group 5400, 6400, 7400 and 1600 had 7'4" - 7'4" wheel spacing. The pre group locos, including the 2021s, all had flat grates, but the 2021 had a longer boiler and firebox (U Class). When the 54 was designed, it had a new boiler, (Std 21) which was an update of another boiler built for absorbed classes which was a sort of U class with a sloping grate and a longer firebox. The later all new boiler design for the 1600 had a shorter firebox like the 2021, but still retained the sloping grate.

A little sideline I spotted reading the NRMS drawing lists is that judging by the drawing dates the 1500s were designed before the 9400s. The 1500 does look like a dedicated shunting locomotive with lever reverse, unlike the 94s and their screw reverse.

 

You don't know the book title and details do you? That certainly sounds as if it could be a sound argument for placing the order at the time they did. I wonder if its speculation or if the author had a source?

 

Note that the Standard 10 was the one fitted to the Taff Vale A class, one of the most modern pre grouping 0-6-2Ts. These were superheated as we're those fitted to the earlier 9400s. However later 9400s weren't superheated suggesting a change in their role tending towards heavy shunting rather than main line traffic.

 

Surely the "copy" element was the 0-6-2T wheel arrangement - the use of standard Swindon components and principles was not part of that equation.

 

That's a very good point. The Rhymney P, AP and A classes also had the Std 10. Those classes were just about all Red route, power class C, like the 94s, whereas the 57s where yellow route and had less adhesive weight, which I suspect was rather important taking coal trains down the valleys. So the 94s had the same power, braking adhesion and boiler capacity as the 0-6-2Ts they were replacing, but more 57s would not have had the braking or boiler capacity.

 

If I recall correctly the wheelbase was exactly the same as the Rhymney locos.

 

I believe you're right. The 5600 does rather look as if, to mirror phrases Holcroft used about a couple of jobs he was given, a roll of musty old Rhymney railway drawings were deposited on someone's board, and they were instructed to get out a GWR version and bring in all the standard features they could.

 

i think the 94xx would have been chosen for their greater adhesion and braking, being heavier.

As regards a waste of money, well, in hindsight perhaps but from a 1946 perspective, no. I doubt British industry then had the capacity to build huge numbers of shunters and in any case as already pointed out, these locos were not primarily shunters.

 

Possibly works capacity has a bearing. A huge number of locos would have been pretty knackered after WW2 and maybe it was decided to scrap as many as possible and replace them. Obviously many of the locos needing works would have been Panniers too

 

I read that the Southern was also profitable, in addition to the GWR

 

It seems unlikely, payment would have been made on delivery not at the time the order was placed and I'm not sure on what basis compensation was actually paid to shareholders. Does anyone know?

I don't know the terms of nationalisation, but if the locos weren't required then I would expect there to be some form of cancellation, or the government not to honour the contract.

More likely, as others have said, post WWII there was a desperate need for workable locos.

 

So it seems the Southern had a desperate need to spend money too ... Is that why they ordered the Leaders when a pannier tank would have been an economical alternative?

 

indeed, they were effectively screwed over by Bulleid pursuing his own engineering dreams when there was an urgent need for tank engines in good order. He did the same in Ireland too, but was cut short by early dieselisation

 

Shareholders were compensated based on share prices in 1946. It is not clear how converting cash to locomotives, even with the benefit of foresight, could have boosted the share price.

 

Quite. If anything it would push the share price down, although in those days the market was rather more opaque than these days lm

 

Interesting thoughts folks. I wonder what sources there are on the finance. I've found nothing helpful at Kew about why the 94s were built, but I haven't looked at the financial records: I lack the experience/knowledge to understand properly what I would be looking at!
One might also speculate that the GWR directors wanted to ensure that their healthy renewals fund was spent on locomotives for the (G)WR, not diverted elsewhere, but that's just evidenceless speculation.

I don't think there's any doubt that withdrawals of pre group locomotives had been delayed by the war: its easily seen on the class records. 5700s had continued to be built during the war - a good couple of hundred I think with a quick scan on RCTS. There was definitely a very big clearout of 19thC and non standard classes from 1946 to 1951.

I've done some sums quickly. There could be errors, especially with the absorbed classes, but I reckon this is roughly right.

On 31st Dec 1947 the GWR had, excluding dock tanks, other specials:-

931 large 0-6-0T (10 classes, 99 pre group in 8 classes, mostly Swindon built)
236 small 0-6-0T (9 classes, 171 pre group in 6 classes, mostly Wolverhampton built)
384 0-6-2T (10-15 classes , depending on how they are classified, 184 pre group, all absorbed)
-------
1551 (1215 0-6-2s and large 0-6-0T)

In about 1958, when all pre group had gone and all new classes built
1073 large 0-6-0PT (5700, 9400)
185 small 0-6-0PT (5400, 6400, 7400, 1600)
200 0-6-2T (5600)
--------
1458 (1273 0-6-2Ts and large 0-6-0PT)

Also worth noting that at that date all the other regions had numbers of 19thC 6 coupled tank classes left.

 

so 140 extra large panniers and 185 less o-6-2T. Given the overall shrink in the fleet, that more or less tallies with 94xx replacing pre group Welsh locos.

 

I don't have the data, but I suppose that BR standards should be added to the list. However my 1958 Observers suggests that the only other BR era tank engines were 20 5101s and a similar number of BR Standard 3s, and I reckon roughly that number of earlier Churchward 2-6-2Ts had been withdrawn by the late 1950s. Loco committee minutes from the 30s, where they do list what classes were replacing what, suggest that the general trend in GWR policy was to have fewer more powerful locomotives.

 

How did Europe manage then post 1945?

AFAIK there was not a lot of steam construction & almost all nations finished steam building by 1955.

Didn't Dutch Railways end steam by 1953

 

I think it may be the Marshall Plan without researching it. US supplied locos