[astrayelmgod]

Model Railroader Books has "Model Railroad Bridges and Trestles" which has plans for two, a Scherzer rolling lift bridge, which is the fancy Bascule, and a very plain bascule bridge that looks more like a plate girder bridge that goes up.

The book is so old that I think George Stephenson contributed to it, but it is still in print. I got mine from a local hobby shop, but I see Amazon has it in stock.