GWR 39xx class

When the GWR rebuilt some of the Dean Goods into 2-6-2Ts was the working pressure of the new boilers 180 psi, thereby retaining the tractive effort of about 17,000 lb? Or were they set at 200 psi which would have been the pressure the new boilers were designed for, being, from memory, a standard Number 4, and do raising the tractive effort to around 20,000 lb?
If the latter, what effect did it have on the mechanics of the loco?

 

According to Russell the 39xx were fitted with a No5 boiler pressed to 180psi. I seem to think that the No5 was quite a bit smaller than the No4 and similar to a No2.
Ray.

 

Even smaller, same as 4400/4500 small prairies

 

"Standard No 5" is the boiler type used on 4500- class "small prairie" tanks. Quite a number of them still around.

 

Of course - I should have remembered that! Thanks Lester.
Ray.

 

According to RCTS the boiler pressure varied. It was originally 2oo psi, but later on 165psi on some, 180psi on others.