Rapido OO Gauge GWR 44xx/45xx/4575 Small Prairie

[The Johnster]

Good point, ma'am.  The tiny wheels draw attention on a 44xx, a part of the gawky awkward (or is it awky gawkward) character of this rather individualistic design.

[The Johnster]

Just now, tomparryharry said:

From here, it looks good. I wonder if Llantrisant ever borrowed a 44xx tank?

 

If Tondu ever used one to cover for a failure on one of the mountain branches, which would be my Rule 1 excuse, I'm sure they would have been happy to lend one to Llantrisant, probably sending via Bryncethin-Llanharan to keep it off the main line as long as possible.  Perhaps cover for a failed 1471 on the Penygraig; 44xx were known good hillclimbers!

 

There were three allox TDU at a time, two to work Porthcawl and a spare to cover failures, washouts, &c, so there would have been a spare available for a good bit of the time, especially if it's only up the road and can be retrieved at short notice.  This will be my excuse for the appearance of one on the Cwmdimbath pickup...               

[Miss Prism]

Oooo-errr, 4402, 4403 and 4408 got 12-spoke (probably Swindon) drivers in later years.

 

[RapidoCorbs]

28 minutes ago, Miss Prism said:

Oooo-errr, 4402, 4403 and 4408 got 12-spoke (probably Swindon) drivers in later years.

 

I think 4402 only got new rear driving wheels as the other two pairs look to be 10-spoke. I would guess that for some reason (damage/wear?) they needed replacement and Swindon had standardised on 12-spokes?

4403 seems to have gained them earlier than the others so perhaps the castings were made for 4403.

 

 

 

[Miss Prism]

13 hours ago, RapidoCorbs said:

I think 4402 only got new rear driving wheels as the other two pairs look to be 10-spoke. I would guess that for some reason (damage/wear?) they needed replacement and Swindon had standardised on 12-spokes?

 

Usually, wheel centres were retained, old tyres knocked off and new ones fitted. I'm not aware of damage occuring to wheel centres, but I suppose it could have happened, and maybe spares of the 1906 Wolverhampton centres were no longer available. Easier to nick an axle's worth off a retiring 850 loco.

 

(There was a RMweb debate about the Hawksworth 16xx crankpin throw, but I can't remember what the conclusion was.)

 

[tomparryharry]

There s a direct correlation between cylinder stroke and crankpin throw. You cant have any discrepancy, otherwise the pistons will be playing 'peek-a boo'....

 

As far as coupling rods are, I thought the initial wheelsets were altered in relation to the crankpin-knuckle joint. The 45xx being the improved version, and the 44XX  being the original layout. 

 

Researchers please note that I might have got it wrong, so some further looking is required. After all, it's what our forum is all about...

[Compound2632]

9 minutes ago, tomparryharry said:

There s a direct correlation between cylinder stroke and crankpin throw.

 

On outside-cylindered engines, that is - physically, the crankpin throw determines the piston stroke, though in design terms the relationship is the other way round. 

 

The tyres would be re-profiled from time to time, without removal from the wheel centres. Is it possible that an engine going through the works would be re-fitted with the first available re-profiled wheelset, rather than its return to traffic being held up for the reprofiling of the set it came in with; thereby accounting for these mis-matched wheel centres? No need to postulate damage to the centres.

Edited December 3, 2023 by Compound2632

[tomparryharry]

Russell's Vol2 shows a 45xx with the coupling rod knuckle behind the centre crankpin...

[Miss Prism]

As it should be on a 45xx.

 

[The Johnster]

Would this be part of the process of reversing the frames, and hence the axle spacing, between the 44xx and 45xx designs, which is what prevented me from fitting a Baccy 45xx chassis under a K's 44xx kit bodyshell and attempting to re-wheel it (may have dodged a bullet there)?

[JimC]

Another difference was that the bearing for the coupling rod (but not the connecting rod) on the driving wheel was 1/4 in larger on the 45. All the others were the same though. Unfortunately the 1942 list of bush dimensions I have a copy of doesn't list dimensions for any of the pre Churchward 0-6-0T (or of course, the Hawksworth ones!). The dimensions for the 54/64/74 bushes, which I suppose might be similar to 2021s, are rather different from the 44s, suggesting that wheels wouldn't have been interchangeable between 44s and 850s->2021s without crankpin changes.

Edited December 3, 2023 by JimC

[Miss Prism]

Use of 2021 wheels on 44s/45s can be ruled out because of their crankthrow.

 

[tomparryharry]

15 hours ago, Miss Prism said:

Use of 2021 wheels on 44s/45s can be ruled out because of their crankthrow.

 

More importantly, the 44xx is outside cylinder, whereas the 850/2021 is inside cylinder.

I still can't find a decent photo of a 44xx coupling rod knuckle joint. 

[Miss Prism]

You have to take the conn rod off first.

 

[34theletterbetweenB&D]

On 26/11/2023 at 19:27, The Johnster said:

...Is this an actually sliding sliding cab side shutter I see before me, the handle towards the rear and a different piece of plastic to the red bits?  If so, kudos Rapido, TTBOMK a first for RTR

Not so. Hornby on their very fine Bulleid Q1, circa 2004, sliding shutters on the tender cab. The etched frame representation under the loco cab is also notable. 

[tomparryharry]

1 hour ago, Miss Prism said:

You have to take the conn rod off first.

 

I think we're talking at cross purposes here. For he sake of clarity, shall we start again? 

[Miss Prism]

Of course, but I'm not sure where we started from.

 

[tomparryharry]

54 minutes ago, Miss Prism said:

Of course, but I'm not sure where we started from.

 

Aren't we all!

 

[RapidoCorbs]

On 02/12/2023 at 10:29, rprodgers said:

If I may ask some questions for Rapido @RapidoCorbs with regard to the 4400 (early 1920s) version, will the copper cap and safety valve be a painted finish copper / brass ?
 

If so I think I will be looking at 4408.

 

Will all the GW versions (from the two earliest to the last two) be the same shade of green ? 
I know that there is not universal agreement on any change to GW green. Albeit there are later anecdotal tales of Swindon thinning down the paint that once fired the loco’s  green paint darkened.

 

Looking good !

 

 

Sorry I missed your message. I'll need to check our samples ref. colour as I am working from home today and not got my swatch box to hand. I think it may be that the eras represented by the tooling didn't see a change in green shade. But at the moment the plan is for them all to be the same green with just the decoration changing.

Chimney and safety valve - yes copper cap and safety valve cover painted brass colour on 4400 but black and green respectively on 4408. 

[tomparryharry]

If we swing over to GWR.org site, there is a Mitchell kit of a 44xx by Ted kanas. 

 

Opinions, please?

 

 

Edited December 4, 2023 by tomparryharry
More information.

[rprodgers]

1 hour ago, RapidoCorbs said:

 

Sorry I missed your message. I'll need to check our samples ref. colour as I am working from home today and not got my swatch box to hand. I think it may be that the eras represented by the tooling didn't see a change in green shade. But at the moment the plan is for them all to be the same green with just the decoration changing.

Chimney and safety valve - yes copper cap and safety valve cover painted brass colour on 4400 but black and green respectively on 4408. 

@RapidoCorbs sorry not necessary I only tagged you today ( you shouldn’t be pestered weekends).

 

Thank you for the reply, much appreciated.

The issue of GW paint is contentious some authorities state the GW green pre 1928 was a darker shade, including the paint manufacturers- Precision, Railmatch and Phoenix.

 

[Miss Prism]

16 minutes ago, rprodgers said:

The issue of GW paint is contentious some authorities state the GW green pre 1928 was a darker shade, including the paint manufacturers- Precision, Railmatch and Phoenix.

 

Bob Shephard, who was Mr Precision up to 2004, was firmly of the opinion that the paint was the same, and it was only the additional varnish coats in earlier years that made it look darker. See http://www.gwr.org.uk/liverieslococolour.html

 

I'm not taking sides on this issue.

 

[rprodgers]

22 hours ago, Miss Prism said:

 

Bob Shephard, who was Mr Precision up to 2004, was firmly of the opinion that the paint was the same, and it was only the additional varnish coats in earlier years that made it look darker. See http://www.gwr.org.uk/liverieslococolour.html

 

I'm not taking sides on this issue.

 

That’s interesting it explains why Precision Paints (and other paint manufacturers) sold two different shades of GW green- pre & post 1928.

In a similar way to coaches the varnish darkening the pale upper panels to make them appear cream in earlier days.

 

I guess the  application of extra coats of varnish would also cause a further darkening as the varnish aged.

 

I recall reading in a book(s) that at a later tale, at I think at an absorbed company loco depot they complained about the poor Swindon paint specification.

The paint was specified to be thinned that much that the green boiler turned almost black on its first firing.

 

Edited December 5, 2023 by rprodgers

[melmoth]

6 hours ago, rprodgers said:

 

I recall reading in a book(s) that at a later tale, at I think at an absorbed company loco depot they complained about the poor Swindon paint specification.

The paint was specified to be thinned that much that the green boiler turned almost black on its first firing.

 

 

John Gibson tells that story in his "Great Western Locomotive Design" (David & Charles, 1984, isbn 0715386069). It happened at Cirencester works on the MSJWR. where Gibson was an apprentice (if I remember correctly). The works was given the job of repainting a Dean Goods and put in a request to Swindon for 8 gallons of green paint. Swindon sent them 2 gallons.

[Harlequin]

13 hours ago, rprodgers said:

That’s interesting it explains why Precision Paints (and other paint manufacturers) sold two different shades of GW green- pre & post 1928.

In a similar way to the varnish darkening the pale upper panels to make them appear cream in earlier days.

 

I guess the  application of extra coats of varnish would also cause a further darkening as the varnish aged.

 

I recall reading in a book(s) that at a later tale, at I think at an absorbed company loco depot they complained about the poor Swindon paint specification.

The paint was specified to be thinned that much that the green boiler turned almost black on its first firing.

 

 

Another factor which could have affected the appearance of Locomotive Green is the "lead paint act" of 1926. The original formulation of the paints involved quantities of poisonous white lead and we know that even before this time the GWR were mindful of the hazards of using lead in paint because of the minutes of the "GWR Paint Committee" (who dealt with the fixed structures only, not rolling stock). They were actively involved in reducing the amount of lead in the Standard Tint paints. It's reasonable to assume that a similar process was undertaken for the paints used on locomotives.

 

Edited December 5, 2023 by Harlequin