Hi WD. Thanks for your inrerest in the trolley. Sorry, I don't have any plans for this model. I just built it as I went along using simple tools. The axle that you see in the picture is a hollow tube soldered onto the rails, and the wheel shaft rides in the tube which was notched to accomodete axle and drive gear. Same with the crank and the other set of wheels. I'll try to draw up and post a sketch. It was a fun and simple build. Ralph