HERSHEY, Pa. (WHTM) — Roller coasters get their speed from many different ways. It could be that the train is pulled up a tall hill by a chain or cable, or can be launched with the use of magnets.
There is one method that some coasters use that launch the train so fast, that it is used on the world’s tallest and fastest coasters in the world. That launch is the hydraulic launch method. This launch method is used locally on Hersheypark’s Storm Runner.
There are four basic components to a hydraulic launch. They are hydraulic motors, a catch car, a winch, and a cable pulley system.
According to NTS, each launch cycle starts with pumping hydraulic fluid into several storage containers. Each of these containers is divided into two compartments. One is for the fluid, and the other is for nitrogen gas.
While the hydraulic fluid is filling one compartment, the nitrogen in the other compartment becomes compressed. Once it gets to a high enough pressure, the hydraulic fluid is stopped and the gas moves into a cylinder
While this is occurring, a catch car is sent down to the beginning of the launch track. This mechanism is what pulls the roller coaster train down the track. Around 5 seconds before launch, the train will slightly roll back to engage with the catch car, and hundreds of magnetic brakes will lower.
Five seconds later, the pressurized hydraulic fluid powers many motors all connected to a single ring gear. This gear transfers power from the engines to the winch.
This winch spins extremely fast and pulls the cables attached to the catch car down the track. The catch car and cable are in a separate trough embedded in the track. Once the coaster reaches top speed, the catch car is slowed by magnetic brakes in the trough, and the coaster travels on its own momentum. This leads to an extremely smooth launch.
As soon as the catch car releases the coaster train, it begins to decelerate rapidly to get ready for the next train. The return cable pulls the catch car back to its starting point, and the motors crank the winch in the opposite direction to get it ready for the next launch. The process is then repeated for the next train. You can see this in the video below:
Sometimes, water is sprayed on the cable, due to the intense friction caused by the launch and pulley system. This can be seen on Kingda Ka’s launch at Six Flags Great Adventure.
These motors power the world’s fastest roller coaster, Formula Rossa, which launches from 0 to 149 miles per hour in 5 seconds.
Click here to see a large hydraulic motor that was on the now defunct Top Thrill Dragster coaster at Cedar Point looks like it launching a train. The one on Storm Runner looks similar, but it is smaller in size.