A Webberized Mikado

Mr Webb built a simple 0-8-0 locomotive having 240 litre cylinder volume and a three cylinder compound with 320 litre.The compound was better and more were built and hauled coal for many years.
The first P2 with 220 psi had 445 litre and a 250 psi version can thus have 395 litre for same tractive effort.
A Webberized version shall thus have 33% more that is 525 litre.
If we allow GWR strokes of 30 inch we shall have two external high-pressure cylinders of 15 inch diameter and a single inside of 30 inch.
Two 15 inch cylinders can evidently be further apart than the 21 inch cylinders of the first P2 for a given loading gauge.
It will also allow plus-minus one inch horizontal movement of first coupled axle giving less track stress.

 

Mr Eigthpot has kindly shown a drawing of the original P2 cylinder and asked for a comparison to a Webb version with 50 mm flexibility of first coupled axle.

LNER mainline gauge must have been wider than 8 feet 8 and the prince of Wales P2 will have smaller cylinders to clear present gauge.
The outside LNER cylinder-center was 1022mm away from centerplane and I doubt that the P2 no 7 can be closer.
The Webb version can have an 15 inch cylinder 1050mm away and still clear present loading gauge as shown .

 

Mmmm..... Am I the only one thinking "high centre of gravity"? It's an issue which bedevilled more than one design. Just on the "Brighton", the B4x and D1x rebuilds come to mind.

 

A picture of Gressley and Webb- like cylinder P2 and smokebox within a loading gauge with 8 feet eight platform edge distance

 

The first six P2s were rebuilt rebuilt to A2/2 pacifics.Done differently a more economic von Borries Compound respecting shrinking British loading gauges could have been made.






The outside 600mm high- pressure cylinder is 950 mm from centerplane and drives on to first coupled axle inside the coupling rod.




It could also have been made as Sauvage/Smith type three-cylinder compound and still be within gauge.Again the outside low pressure cylinders sit 1900 mm apart

Most powerfull,economic British pacific and best-looking as well?

 

A VonBorries format compound would be lovely to see and to hear. I've always had a hankering for a B&NCR 'S' or 'S1' class 2-4-2t .... but they were 3'-0" gauge, so unless the Waterford and Suir Valley folks fancied one, probably not happening any time soon.

Would a recreated 19th century VonB perhaps be a more likely newbuild candidate?

 

A war time austerity minimum effort rebuild could have resulted in something like this

https://i.imgur.com/QnlK5Tp.jpg

 

Both the GNR and GER loading gauges were 8ft 8in at platform height. I'd be astonished if the LNER gauge was wider. I doubt all 8ft 8in would be available though because of throwover. 9ft was available more than 3ft 6in off the railhead on the GNR. My study needs a LNER composite gauge, I'd like to see one.

 

The Robinson GCR 2-8-0 war engines were 8 feet 10.5 inches over the Cylinders.
LNER bought quite some of them.
The drawing of the original P2 cylinderblock shows 8 feet nine and a half at 3 feet and 6 from rail top
Loading gauge must have been more than 8 feet 8 on parts of LNER