There are two ways to use electricity and magnetism to launch coasters: Linear Synchronous Motors (LSMs) and Linear Induction Motors (LIMs). LSMs are used on rides such as Superman: Escape from Krypton at Six Flags Magic Mountain and Rock 'n' Roller Coaster at Walt Disney World - Disney's Hollywood Studios. An LSM launch has large magnets mounted under the train that are attracted or repelled by the magnetic field generated by the stators, or stationary windings, embedded in the track. The coaster seen here, and over two dozen other rides such as Flight of Fear at Kings Island and Mr. Freeze Reverse Blast at Six Flags Over Texas, use Linear Induction launches which utalize the stators to create an electric field in copper or aluminum sheets mounted on the cars. LIMs don't require heavy magnets on the trains which reduces weight on the cars, but they is less efficient than LSMs and require more electrical power and produce more waste heat as a byproduct.
©2018 Joel A. Rogers.