Sceme of a wooden roller coaster track and wheels - based on design by John A. Miller, October 28, 1919, United States Patent 1,319,8881: weight bearing wheels
2: sidefriction wheel - to keep the car on the track
3: upstop / under track wheel - to lock the car to the track
4: track with metal armor (red)
5: car
Own work
Stefan Scheer