Jim Champ's "Introduction to Great Western Locomotive Development"

3557, the last survivor of the class, looking in remarkably good condition at Kidderminster in 1932. (With a dinky 2000g tender.)

 

Well, I've made a small amount of progress on my 3521 tank drawing. I found a detailed drawing of the trailing axle assembly of the 0-4-2T version in Ahrons "British Steam Locomotive". Just need the rest of the locomotive now.  GWS, who have a considerably stronger 19thC drawing collection than the NRM, have a fair collection of odd components - much of the trailing bogie is available in detail drawings by the look of things - but no general arrangement or frame plan. Amazing what strange things survive. The NRM do have a couple of weight diagrams, but at 27+ quid a shot and with 19thC weight diagrams typically having next to no detail... Suppose I had better bite the bullet...

See what I mean... Here's where I am. It will be that boiler, although not sure what position, , frame outline on the trailing wheels drawing is from the drawing in Ahrons, frame outline on the driving wheels is from the frames as reused on 4-4-0s and the two don't line up... 

A bit of perusing of drawings tells me that the leading bogie on the odd 4-4-0T pannier tank 1490 is pretty much the same as the trailing bogie on the 3521s, so there's another source...

 

Edited February 2, 2023 by JimC