(WHTM) — Roller coasters are getting taller, faster, and newer every year. It may look like it can be unsafe. But, in fact, coasters are some of the safest machines in the world. Fun fact: The author of this story used to work at Rock ‘n’ Roller Coaster at Walt Disney World!

So, how safe are these machines? To understand how they work, you need to know some of the parts that make up a roller coaster.

Lift Hill

There are two ways a coaster gets its energy. One way is a chain lift or some sort of launch. The chain lift is the most traditional way to get a coaster moving. It involves a large metal chain that hooks underneath the cars of a coaster train and gets pulled up the hill. Sometimes, a cable lift is used. This brings the train up the hill very fast, as a cable lift is lighter. Skyrush at Hersheypark uses the cable lift method.

The famous “clack clack clack” noise that is emitted as the coaster climbs the hill is caused by something called the anti-rollback system. The coaster cars are equipped with something called anti-rollback dogs. These devices bump against metal teeth that usually flank the chain lift. This is in case the ride comes to a stop on the lift hill, the train will stay secure and will not roll back.


The launch catch car on Kingda Ka (Photo: Ryan D.)

Another way to get a coaster moving is a launch. This can be done by large magnets which attract and repel magnets underneath the coaster train to propel it down the tack, compressed air, or a hydraulic launch.

Coasters like Hersheypark’s Storm Runner and the tallest coaster in the world Kingda Ka at Six Flags Great Adventure use the hydraulic launch. These launches are equipped with brakes, in case a train is launched too slowly. This way the coaster can roll back on the launch track and be slowed down to be reset. Rollbacks can happen on very tall coasters, such as Kingda Ka, and are completely safe and are a normal part of a very tall coaster.


Now that you know how a coaster gets its speed, how does it stop? Coasters stop by the use of many types of brakes. A traditional method of stopping a coaster train is by fin brakes. Fins are attached to the undercarriage of the coaster car and slide into a series of clamps attached to the track. When the coaster travels over a sensor near the clamps, the clamps squeeze onto the fin, causing the train to slow. These brakes are fail-safe and are designed to be in the closed position in case of a power failure.

Fin brakes (foreground) and magnetic brakes on Thunderbird at Holiday World (Photo: Ryan D.)

Another way is by magnetic brakes. These brakes do not contact the train, but rather create a magnetic field to have the train slow to a crawl. These brakes are usually supplemented by fin brakes.

Some brakes activate during the course of the ride. These are called trim brakes and trim speed off of the ride during the course. Trim brakes are sometimes installed due to coaster trains taking elements too quickly, sometimes due to weather or other conditions.

Coaster Safety

The safety system that makes sure trains do not collide with each other on the track is something called a block brake system., These are controlled by sensors around the track, which give the coaster computer, called the programmable logic controller (PLC), information on where the train is around the track at all times. Most coasters have two PLCs for redundency, they are the main computer and the back-up.

Both PLCs need to be in agreement for the ride to work. If one PLC detects an error of some kind, that means the computers are not in agreement and the ride will automatically stop.

A coaster’s circuit is broken up into sections called blocks. At the end of each block is a set of brakes that stop the train, in case the block section ahead is occupied. This is how multiple trains can be on the track at the same time. For every train on a coaster, there needs to be one additional block zone. For example, if a coaster has three separate trains, there should be four block zones and one will always be unoccupied.

If the coaster’s PLC notices an error of any kind, the ride will stop all motion. This is what many people call the coaster “breaking down.” This is partially incorrect because the coaster is doing what it is supposed to do. When a ride goes down and there are trains completing the circuit, the train will stop in the next available block zone, keeping all riders safe.

If you see a train stuck on a lift hill with people on it, there is no danger to people aboard the train. The train is secure to the lift hill because of the anti-roll-back devices mentioned above. The park maintenance team will come in to see what error code the PLC is showing and do the required work to fix it.

Usually, coasters just need to be reset (kind of like rebooting your home computer if it locks up) and a test cycle needs to be performed. Coaster sensors are extremely sensitive and can throw an error code even when nothing is wrong with the ride.

Once the reset is performed and test cycles are completed, the coaster can reopen to guests once again.

To show how safe coasters are, according to data from the International Association of Amusement Parks and Attractions, the chance of suffering a serious injury on a ride in an amusement park in the U.S. is 1 in 15.5 million rides taken.

One of the ways to make roller coasters even safer is to listen to the instructions given by the ride operators. Making sure no loose items are on you during your ride will make the coaster even safer for all guests. The ride operators are there to make sure your ride is the most enjoyable ride possible, so it is imperative to listen to their instructions.

Maybe knowing how a roller coaster functions will make you want to ride them even more!