Video

Actually, there is at least one video which outlines the basic signals, it is "Running Steam Locomotives, Volume III, Freight Locomotive Road Operation". I don't know if it's still available anywhere, but there is a segment on hand signals and that formed the basis of my earlier post.
One thing to add, according to the video, and I believe I've seen this on the C&TS as well, is that a trainman can signal the distance between cars by a horizontal wave of his arm. Twice for two car lengths, once for a single car length. Then the "arms wide over his head" stance when the cars are around 10 feet apart.
Don