This is a great site for anyone interested in steam locomotive workings and nomenclature. Check out all the links at bottom of page for excellent drawings and animations.
http://home.roadrunner.com/~trumpetb/loco/locoworks.html
I found the site about a year ago and had it bookmarked. Later the site went down with no forwarding address. I finally found the new site after a lot of searching.
About "Walschaerts", the man.
http://en.wikipedia.org/wiki/Egide_Walschaerts
Enjoy. 8)
Thanks for that. It will some interesting reading.
Bruce