How does the roller coaster work?

What you may not realize as you’re cruising down the track at 100 kilometre hour is that the coaster has no engine. The car is pulled to the top of the first hill at the beginning of the ride, but after that the coaster must complete the ride on its own. You are not being propelled around the track by a motor or pulled by a hitch. The conservation of potential energy to kinetic energy is what drives the roller coaster and all of the kinetic energy you need for the ride is present once the coaster descends the first hill. Once you are underway, different type of wheels help keep the ride smooth. Running wheels guide the coaster on the track. Friction wheels control lateral motion (movement to either side of the track). A final set of wheels keeps the coaster on the track even it is inverted. Compressed air brakes stop the car as the ride ends.