Q1 and B12 valve gear

Some time ago I did a computer model of Stephenson valve gear to help a chap who had made the expansion link radius wrong. None of the other packages would allow this. I've been tidying it up, and am now looking for some typical dimensions to add to the package. With considerable help from Silly Old Duffer, I've extracted some dimensions from the late Bill Hall's program, but when I come to load it into mine I find that it is incomplete. Does anyone have information on the Q1 model which featured in ME some years ago, or the GER 1500 class, later known as LNER B12. I have details of eccentrics, eccentric rods, expansion links and the link suspension, but nothing thereafter, rocker beam etc

Whilst you are looking, the standard GWR setup as applied to Churchward 2-8-0 etc would be nice. According to OSNock, all Churchward 2 cyl locos had the same gear dimensions? Can anyone confirm this?

Failing the above, any full size setups would suffice

Edited By duncan webster on 29/08/2021 20:34:29

The Wallace program has some examples of Stephensons and Walschaerts with most of the dimensions shown. Perhaps you could try some of these in yours. The program takes a bit of familiarisation if you haven't used it.

Thanks Simon, I've just downloaded the windows version from Avocet, I'll have a play. At first sight it isn't obvious how to relate the dimensions quoted to the actual bits

Edited By duncan webster on 29/08/2021 23:54:25

Under " view edit" the dimensions used are shown. Also look at "valving". To test a valve gear design, you really need to draw it in Cad, with the x axis being the line of the motion, not the frames. Then you can derive dimensions not specified, on eg, plans. It is a fair bit of work.

I was frustrated by not being able to analyse Stevos, recently, with the " wrong" driveline, ie, launch links with direct drive to slide valves. I first used Don's Excel sheet to get close with correct suspension pin offset, but can't go forther with Wallace. It is the only simulator I am familiar with. I suppose I could contact Allan Wallace.