Recent Magnet Technology in Roller Coasters
When you’re riding a roller coaster, the last thing you’re thinking is, “What’s the science behind this contraption?” Your thoughts are more aligned with “Yahoo!” or “Weeeeee!” Roller coaster technology is fascinating, though, and it just so happens that it utilizes magnets.
These days, your favorite roller coasters use electrically induced magnetic fields and a launch system to propel coaster trains forward and slow them down. Two primary types of launch systems used are the linear synchronous motor (LSM) and linear induction motor (LIM). LSM is generally the more popular choice, but LIM is cheaper, although it uses more power.
The Launch Process
If a roller coaster is powered by electromagnetic launches, it’s built with metal fins on each piece of track and train. Their fins align, but don’t touch. Usually, a parallel pair of metal fins with a thin gap are built while a single fin sits on the underside of the train. As the coaster passes over these points, it accelerates or decelerates. For example, you could find one of these points right before an upward climb. The specific magnetic fields generated at each of these fin points is specific to a LSM or LIM system.- LSM: This kind of system uses a permanent magnet fin. The two aligned fins should be adjusted for the orientation of the permanent magnet in the train track. First, the train approaches the track fins. A current is generated that attracts the train. As it passes over, it’s reversed by the computer. This reverses the magnetic field and pushes the coaster away.
- LIM: In this case, the coaster fins on the train are made of non-directionally magnetic metal with randomly oriented dipoles. A current is applied to the track, generating a field. The coaster fin is attracted by the magnetic field, causing it to travel forward. When it passes over the track fins, an Eddy current is generated that induces a second magnetic field in opposition to the first. This pushes the train forward.