At a half dozen points during the downhill run, cars pass tires mounted to the side of the track. Some of the larger tires, which look like standard automobile tires to me, are rotated electrically in order to control the cars' speeds. The only brake on the course is located under the awning seen in this picture. Two large bars can extend away from the side of the track and pinch the sides of a car in order to slow it down.
©2020 Joel A. Rogers.