Linear synchronous motor

An LSM-powered lift hill on Maverick at Cedar Point

A linear synchronous motor (LSM) is a form of electro-magnetic propulsion containing no moving parts. The launch system is used to launch a roller coaster train to a high speed quickly. They are a relatively new launch technology and are now favored over the older linear induction motor technology.

The first use of linear synchronous motors for launching a train was in 1997 with the opening of Superman: Escape From Krypton at Six Flags Magic Mountain and Tower of Terror II at Dreamworld.

How it works

The LSM system contains electro-magnets to propel the train to a higher speed. The way it works is by having two pairs (sometimes one) pair(s) of magnetic rectangular fins, the fins produce a North to North magnetic push. as the roller coaster train goes over these fins there are a pair of corresponding magnets that are the same type as the fins. When the two magnets interact the repel each other forwards causing the train to go to high speeds. When the train is not on the LSM's track section the operator or coasters computer system will cut the electrical power to the fins this is only possible because the fin type magnets are electro-magnets, meaning they can be toggled on and off just by turning the power on and off.

Unlike other manufacturers, Vekoma's linear synchronous motor system has some differences. Each car do not have a permanent magnet underneath. A catch car is instead used to attach to the train. When the launch sequence begins, the catch car pulls the train down the track. This was meant to reduce the weight of the trains. The technology is used on Rock 'n' Roller Coaster at Disney's Hollywood Studios, a a clone of that coaster at Walt Disney Studios Park and Xpress: Platform 13 at Walibi Holland.