DX Blocks Roller Coaster models are building block construction kits that let you build a roller coaster that really works, and that you can run over and over again. Just like the real thing, once the car reaches the top of the initial hill, it is designed to traverse the whole track back to the starting point, using gravity and potential energy in the most fun way possible. All of our roller coaster models are very mechanical in operation, with a gear shaft and crank to create that thrilling sense of the initial hill climb, and a unique smoothly operating track system for the downhill and thrills to follow.