For those who may be interested, I have just put up an article written by Maurice Lewman about Hand Signals used on the Big Four/NYC in Indiana. This joins his work on Train Orders and the various Memory page article he has written.
You can access this from my Railroads of Madison County web site at http://madisonrails.railfan.net/ Just take the Memory Pages link.
Oh, he titled his article, "Communications (or how to railroad without a radio)"