Roger, I've just had a look at the link- (http://encyclopedia.jrank.org/SOU_STE/STEAM_ENGINE.html), It seems to me that the article was scanned but not proof read - it certainly appears that tables from the original document have come out something like Eric Morecambe's piano playing - (All the right notes were there, but not necessarily in the right order (sunbeam)). I too couldn't get the links to work properly. "Valves and Valvegears for Locomotive " republished by TEE as ISBN 0 905100 36 0 has a few examples of Zeuner diagrams, but does not cover the Reuleaux diagram. In fact, I'm not certain of the correct spelling - is it "Reau.." or Reu.."? The internet seems trangely silent when searched.... JohnP MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.