Steam Engine Valve Gear on the computer
This link will open to a web site I have no connection with other than I bringing it to via a club member.
Just find the valve gear that you need and down load the zip file unpack it and run the exe file
I have downloaded the File 10K Gresley 3 cylinder and the 10KA Walschaert
I have run both to show you what is all about
Just click play in the normal way if the video did not start