GWR four-cylinder arrangement?

I sort of the agree with the comment about keeping your dreams to yourself but there does seem to be a trend on this forum for passive aggressive attempts (from some quarters more than others!) to shut down comments such as yours. This is after all a DISCUSSION forum so aren't people be prepared to give others the chance to opportunity to put their views forward? You don't have to read them!

 

'Best' is a word rather open to interpretation; you need to specify from which point of view they were 'Best'.

As you say the Compounds had their weaknesses and the main one was size - or lack of it. They were more than big enough for the (relatively) short trains on the Midland with its policy of lightweight but frequent trains, but attempts to introduce this system on the West Coast lines failed due to a lack of paths to accommodate the extra trains. As a comparison, a Compound (rated as Class 4) might leave St Pancras with a heavy train made up to 300 tons. A short walk away a LNWR George the Fifth (rated as Class 3) might leave Euston loaded to 400 to 450 tons, and that happened on a daily basis. The Claughtons and Dreadnoughts certainly had their weaknesses too but ultimately had the shear size and steaming capacity (not a Compound's strong point) to shift the heavier loads.

The Dreadnoughts' main problem was that it was never intended for high speed, long distance, non-stop running: that didn't happen on the L&YR. Instead they were intended for shorter runs with intermediate stops and restarts often against severe gradients. However good the Compounds might have been, they would not have done that on a day-in, day-out basis, or possibly at all. The Dreadnoughts' other issues were high coal consumption and mechanical weaknesses, particularly hot boxes. The former was cured, as it was on other LMS classes, by substituting multi-ring valve heads for the original Schmidt single ring and also eliminating the ball valves in the heads intended to give free running. Even Stewart Cox, who hated everything L&YR (he had been a Horwich apprentice!), reckoned they could be made good and reliable both easily and cheaply, but by that time the Stanier era was beginning and Dreadnought withdrawals had already begun.

The Claughtons were designed for the WCML and were fast and powerful - on a good day anyway. But their performances were inconsistent. Their excessive coal consumption was cured by the same multi-ring valve head conversion but their reliability and repair and maintenance costs were terrible, and there was no easy cure. The LMS eventually 'rebuilt' them with three cylinders, known for obvious reasons as 'Baby Scots', although definitely not by officialdom.

The Compound was a good intermediate express engine but nowhere near the answer to the LMS's needs for express power, even in 1923. This is shown by the introduction of the Royal Scots only four years after Grouping, an engine 23 tons 14 hundredweight heavier than a Compound.

 

If that is aimed at me, then I have no problem with discussion, I just happen to think that Mr Hermod should build a loco if he wants to experiment, rather than butchering historical locos.

 

I don't disagree, in terms of butchering a preserved loco but, in reality, he's only talking about his dreams and if he really wants to go ahead I think we all know what reception he'd get! If you thought the idea of using a Castle boiler to kit-build a 47XX was heresy then..........!

 

I have a Roche drawing for a King class and it seems to have straight frame plates with a cut out where aft bogie wheels are.
The distance from front bogie wheels to front drivers are exactly the same as on LNER B16/1.
A better King can be made by putting a single 23inch diameter /28 inch stroke high pressure up front outside beside a 34inchdia/30 inchstroke low pressure between frames.
A more crack resistant frame can be had if is made of four parts sliced around first driver main bearing bloks.
Best french compound used 11.2 lbs steam to make one ihph. Britania used 13.2 lbs and Kings 13.8lbs all after WW2.
Improving outdated technology is more pleasant than wondering where steel from war austerity scrapped herritage locomotives might end up.

 

Due to scaling factors I think compounding should work better on a miniature engine than it does on full size.
Consider a cylinder which is initially hot, the steam expanding will have a cooling effect, and the heat has to be replaced by the next charge of steam. My understanding of compounding is that there is less steam (or should I say heat?) lost due to this effect in a compound because there is less expansion, per cylinder. Now in a miniature engine the mass of metal is greater, when compared with the mass of steam, so the benefit of compounding should be greater than for a larger locomotive.
I hope this all makes sense! Compounding was more common on traction engines, but then again so was steam jacketing, On a traction engine, with the cylinders mounted on top of the boiler, it was easier to arrange for the condensate from the steam jackets to drain directly back into the boiler.

 

I have received a scan of a King GA and can se that outside cylinders (16.5 inches inner dia) are 7 feet 2inches apart.
On GWR mainline running straight forward there can thus be two outside cylinders of 26.5 inches dia 6 feet 4 apart.
(Midland compounds had cylinders 6feet 3 apart and the Adams 4-4-0 was 6 feet 2).
Two King cylinders can be substituted by a single 22.5 times 30 inch cylinder so gauge clearance will be OK.

 

The tonnage is not relevant as it is minimum steam consumption per indicated horsepower hour.
Russia used more than 5000 two cylinder compound 0-8-0 locomotives.
I intend to have an outside frame,inside low pressure cylinder and valve,inside frame and single outside high pressure cylinder.

 

Spot on and explain why four small King cylinders were not as frugal as two from Britania.