JimC

23 hours ago, Compound2632 said:

, but an increase in capacity would, if the renewal was on a vehicle-for-vehicle basis, require additional capital expenditure to be authorised. 

I haven't looked into wagons, but for renewals of locomotives on the GWR post grouping a nominal value was placed based on locomotive weight, so n 0-6-0s would be renewed as n-1 4-6-0s. If a similar policy existed for wagons one would indeed expect 2 x 10T brake vans to be renewed as 1x 20T.

[Next Day] I had a quick look at a few years of GWR minutes, but in the ones I looked at I didn't see brake vans listed separately.

Are you aware aware there are short cone and long cone taper boilers? That looks to be long cone I think (D3 in RCTS parlance) . There are also variations in smokebox length to consider - if I read photos right that's a longer one.  According to RCTS few received top feed *before superheaters* and the first with top feed was March 1911. I fear it's going to be tricky to pin down that exact config without finding a photograph. TBH you could consider leaving be until/unless evidence turns up that it's not right as 3345/Smeaton.

7 hours ago, FraserClarke said:

The view that Didcot is obsessed with new builds and just leaves everything else in the shed doesn't really hold up to the numbers... 

Agreed. There are also signs of a major changing of priorities at Didcot in recent years. The line of tatty wagons outside the locomotive shed has had considerable cosmetic and maintenance attention and looks far better than it did. The buildings, infrastructure and visitor facilities have been bumped up in priority. The 47xx has always been somewhat at arms length, which may have been part of the problem, and doesn't take up any Didcot volunteer resources, while the 4-4-0 County has been pushed out from under the Didcot umbrella completely. The long term desire for a Dean Single build appears to have been firmly shoved to the back of the cupboard. Most the emphasis on the GWS website is on overhauling small engines and buildings and infrastructure, although one shouldn't forget excellent work being done in the carriage department. 

45 minutes ago, Hal Nail said:

yes the way I read it, the argument posed was that the money spent on new builds could be used to get locos running again.

In the case of the  GWS projects by and large it couldn't, because there are separate appeals for different projects and the money is ring fenced. No doubt there would be arguments that the money would be donated anyway, but I suggest at best that's no more than partly true. 

On 28/03/2023 at 07:13, rogerzilla said:

2. SR happily sent Lord Nelson drawings, and parts of the firebox design were used.  Holcroft said it was more than that, Cox said that was all.

On 28/03/2023 at 07:32, LMS2968 said:

The LN and Scot fireboxes show similarities in profile but are very different in end view. Eric Langridge, a draughtsman at Derby, a was equally adamant that the Scot owed nothing to the LN design.

I think if you give a talented design team a set of drawings to use as inspiration/guide  they use the information as inspiration and influence without actually tracing individual parts. It doesn't bear thinking what the morale situation must have been in the LMS design office when the senior management delivered such a massive vote of no confidence in their own people as they did when rejecting an in progress in house design in favour of external contractors. It's little wonder everyone has their own spin on it.

It seems to me that another way of interpreting the Jubilee/high superheat thing is to note that Churchward's boilers with moderate superheat worked just fine, even on exchanges with LMS and LNER using local coal. If the jubilee boiler couldn't steam with moderate superheat but the Castle boiler could, does that indicate that there was something not quite right about the Jubilee boiler and/or draughting?

1 hour ago, Mike_Walker said:

They were built for a specific purpose, principally fast overnight fitted goods trains where as the 28xx were designed for slow mostly mineral trains.  There were only 9 47xx's because that was all that was needed.  Both types were very successful and even got pressed into passenger service on summer Saturdays - with preference given to the 47s.

Its maybe a little ironic to note that Cook tells us the running department put in a request for more 47s, but Collett elected to build a batch of Castles instead as being more versatile even though more expensive. The other thing to note is that WR thought it justified to build a new set of boilers for them in 1955-7 which suggests it was thought they would run for many more years. One might observe that fitting Castle boilers instead of a new batch of Std 7s might well have been a cheaper option since one fewer would have been needed.  There was also a plan to fit screw reverse to them in the 1950s, although this went no further than the drawing board.

9 hours ago, MPR said:

The wheel spacings are the same, but the articulation between the rods was forward of the middle wheel on Stars and early Castles, 

The coupling rod bearing on the Castle driving wheel was larger too.

https://www.railwaysarchive.co.uk/documents/MoT_Beighton1942.pdf

This is what I've sketched up from the drawing in GWW and information above. Dimensions in inches. No guarantees its correct and any required corrections welcome. It would be interesting to have widths for 1, 2 and 3 digit plates.

 

2 hours ago, tanatvalley said:

 See https://www.gwra.co.uk/auctions/bycategory/13/53/Cabside-Numberplates.html

Yeah, I tried scaling off those, but there's just enough camera distortion that I didn't think it reliable enough. 

Trivia. In general three figure plates all seem to be a standard width (unsure whether iron different as per 4 figure), also probably two figure, although not many of those to work from. But 111 appears to have had her own no-standard width cabside. 

8 hours ago, tanatvalley said:

The height is the same as the brass plate, 11.75in. Also the position of the 4 keyed fixing holes are the same for brass and cast iron.

So the end screws are slightly further from the edge of the cast iron plates than the brass ones? Was the raised border the same distance from the edge on both?

Yep, its a vector drawing. Most use if drawing your own plates. I've got reasonable outlines of all the numerals on there.

Alan, that's a useful observation and probably  explains some inconsistencies I was seeing scaling from the photos on the Railwayana site . Do you have any of the other dimensions for iron plates? 
I'll look at working up a dimensioned jpg.

Hopefully this is to scale 1 mm to 1 inch and will work for people. 
I've worked it up mainly from railwayana photos. The narrower plates are estimated widths from the photos.

GWRcabsidenumerals.svg

According to a drawing in Great Western Way, 2'1.25in * 11.75in, but 1, 2 and 3 digit ones were narrower. I think that's over the polished brass outline rather than the actual edge of the plate though.

2 hours ago, Happy Hippo said:

 

Since the boiler overhaul regime was on a different schedule to a loco going through the works, I would suggest that if the boiler was appropriate for the loco, it came off the front of the line of available boilers.

Indeed, but according to the numbers in RCTS there weren't any spare non-super Std 10s to form a pool for the 94s and 15s.

Rcts records various boilers being converted between superheated and not in the first quarter of 20thC, but not Std 10s. As you say a very big job, but they did have all the facilities. 

So it appears to me we are left with 4 possibilities

1.superheated boilers were fitted on externally built 94s, with or maybe even without the actual superheater elements and header. 

2. Some super-standard 10s were rebuilt without flue tubes and used for a pool, even though RCTS doesn't mention it. 

3. RCTS has got the total of non-super Std 10s built wrong. 

4. There was no boiler pool for the non super Std 10s.

None of these seem especially likely! 

3 minutes ago, Happy Hippo said:

The first 10 of the 94xx panniers were superheated. The rest, plus the 84xx and 34 xx classes were not.

That's how they were built, yes. Did they stay like that? I've seen it said 9400 no longer has a superheated boiler.

IIRC according to RCTS only enough saturated Std 10s were built to fit the 15s and the 94s with none spare for a pool. There must have been superheated Std 10s reasonably available from the pool for 2251s and absorbed, plus more freed up as absorbed locomotives were withdrawn while the 94s were being built. Were s/H superheated boilers retubed? RCTS doesn't mention it AFAICS, and it does for other types. Were the 10 superheated locomotives allocated separately? Did superheated boilers migrate round the fleet? I haven't managed to find any of this out. I must get to Kew and look at boiler records to see if there are any clues. 

2 hours ago, Happy Hippo said:

As Phil points out the bulged cover plate is for the oil feeds. The oil feed pipes under the boiler cladding needed to be lifted clear of the join where the boiler cladding met the smokebox ring.  The cover was removeable to give access for inspection and maintanence when required. 

 

A superheater is just a series of pipes that carries steam from the regulator back down through the enlarged superheater tubes in the boiler. The tubes may go back and forth several times before being delivered to the  steam chests and thence to the cylinders.

 

Most GW loco had hydrostatic lubricators whereby oil was introduced into the steam to lubricate the  steam valves.  

 

When the change to a higher superheat was made to certain locos, the hydrostatic lubricator was not as effective, so a change to mechanical lubricators was made.

 

This resulted in a change to the piping arrangements on the rhs of the boiler, which created the larger and more obvious covered plate as shown in the picture.

 

[This is a very simplistic explanation.]

 

 

 

 

Trouble is there are also oil feeds on the saturated types, if not as many. I'm glad I'm not the only person who's wondered what on earth it is that is visible. Pre group and 94xx panniers are the ones where I'd very much like to be able to tell and haven't managed to.work out a way. 

No, that's the 4 cone ejector. 

I think everyone who has written books or magazine articles knows the temptation to use a good story that has slightly dubious provenance or has been exaggerated just a tad. Lets face it we've all come across tales that have grown in the telling.  And its also going to be the case that not every story told in the first person actually happened to that individual. 

As for Tuplin: well he definitely has, shall we say, a weakness for a good story. The other one I take with a bit of a pinch of salt is Gibson's "critical appreciation of GWR locomotive design" where I've found a number of places where what he has to say literally doesn't add up!

1 hour ago, rodent279 said:

What if you made all 4 cylinders into one casting, all in a row?

 

How does that work with clearances vis a vis the wheels? Obviously there are ways and means to juggle it a bit, but isn't the main limiting factor the need to have the connecting rods in line with the piston centre and reasonable bearing widths for connecting and coupling rods? 

I suppose one should add that problems of water supply, quality and cost were a major preoccupation to the railways. From my readings of GWR minutes the cost of water supplies was always discussed, and water supply contracts etc were a significant preoccupation at director level in the GWR. Improving water quality was also a priority, because better water meant better boiler life and had a very great influence on running costs. In his book Ken Cook records how Swindon made big improvements in boiler life through both selection of supply and installation of water softening plants. 

There was also the load problem. AIUI most vans ran at best part full, hence the later development of partitioned vans. No point in a 20T van with 6T of merchandise in. 

I think a drawback with superpowered 1840s locomotives would have been the same one that largely prevented superpowered locomotives in the 30s - the rest of the infrastructure. Double the train weight and how are you going to stop it? I don't suppose there was much in the way of refuge sidings etc at that time either.

Fair enough, the specific example doesn't work on inspection, but I think the point remains that different technology /operating patterns could have led towards different working patterns and different solutions. I'm not one of those who believes our ancestors were fools, but sometimes with the benefit of hindsight we might be able to imagine feasible alternatives.

14 hours ago, rodent279 said:

They weren't, the schedule was something like 8 hours for what? about 140 miles. Lots of standing around in loops & refuge sidings, lots of toddling along at 25mph at best, not ideal for turbines.

OTOH that's a ridiculous way to run a railway. Desperately expensive. Now supposing the mineral business could be migrated to 12 ton or 16ton containers loaded in 3s and 4s onto converted coach chassis as flats? Existing coal handling facilities modified to suit the containers, which aren't so very different from the PO wagons in size. Maybe the same to general freight traffic. Now we have a freight traffic that can run at stopping train speeds. What's going to be required?