The One About Malfunctions

By: William Supko

Once again an article has surfaced stating something along the lines of “a ride has malfunctioned causing a train to stall around 200 feet in the air”. Add in a long wait to get off, the fact that it's the third time in a week and fail to mention that this happens daily in the amusement industry and it's a perfect media storm.

You end up with comments like “no way”, “they're not safe” and “tear them all down”. How about instead of trying to generate fear and panic amongst amusement park goers we educate them on how these extreme scream machines operate, and operate VERY safely.

A block check is preformed on Fury325 before it's open to the public every day.

There were approximately 67 deaths from both mobile and fixed amusement devices in the United States from 1987 to 2004. This means there is far more risk of death while traveling to the amusement park than there is once your inside the gates.

You may be wondering why this ride would halt on the lift if these rides are so safe. The reason for the stoppage is a preventative measure. Sensors around the ride monitor the roller coasters speed and location throughout the ride on most rides. Sensors on the ride can determine if the lap bars are up or down, if the air gates are open or closed, if equipment is functioning properly (including the lift chain, air compressors and braking components). If any of these functions fail the ride will shut itself down to prevent any serious accidents.


The ride will only stop in designated areas with almost all ride break downs.  Roller coasters run on gravity from the time the leave the lift hill until the time they hit brake run areas.  There are times when a coaster doesn't navigate the entire track.  This is called valleying and it happens very rarely.  The main reason for valleying is that it's to cold to operate the ride.  Something getting jammed in the wheels or a wheel assembly failing is another reason a train may halt where it's not suppose to. 

A roller coaster uses block sections to prevent two trains from running into each other. The blocks

Sensors on Maverick - One set lets the ride know the train
has exited one block and the other set lets the ride know the
train has entered another block.

usually consist of the lift, the running track, block brakes, holding brakes and the station. The ride will shut down all or part of its components (closing brakes, stopping the lift chain) in the event that two trains come too close to each other. In some cases these rides are designed to restart immediately once the situation has been rectified.

Most roller coasters use two sets of sensors to monitor where the ride is at. If the sensors sense the train at the same time the ride will run normally. The ride will stop itself in the event that one sensor is triggered but the other is not. This is called a PLC (programmable logic controller, or the roller coasters “brain”) mismatch and is where a majority of ride breakdowns come from.

There are several reasons for PLC mismatches. The system will read an error when a sensor goes off line or malfunctions. Things like spiders, dirt and leaves can trigger the sensor causing the system to think a train has passed by when it really hasn't. Sometimes the sensors may be triggered out of order which will cause the system to shut down.

Block brakes on rides like GateKeeper stop a train if the train before it hasn't
made it back to the station.

Power failure is another reason a coaster may stop.  Gravity will once again take over if the ride has crested the lift hill before the power fails.  In the event that the power fails all braking mechanisms are designed to go into the closed position.  This prevents trains from running into one another when the power goes out.

A majority of attractions are designed to be idiot proof. Trains can't leave the station with the lap bars unlocked. The system will not allow trains to be dispatched when the gates are open. Some ride manufacturers are now putting limit switch sensors in the seats that require all restraints to be down to a certain position before the train can leave the station.

There is a HUGE amount of redundancy in the production of amusement park equipment. Roller coaster seats come with a double locking mechanism so that in the event that one fails you have the second one there to hold you in. Another important thing to know about amusement park accidents and deaths is that a majority of them are due to either rider or operator error, not the equipment.

Safety at an amusement park is priority number one.  The maintenance department works very hard to maintain a ride.  Checklist and maintenance procedures are created for items that need to be taken care of daily, weekly, monthly and yearly.  Seasonal amusement parks use the off season to tear apart and rebuild many components of the ride while analyzing pieces for stress cracks.  Year round amusement parks will use a slow time of the year to close down and overhaul a ride.  Once maintenance hands the ride over to the operations team they will monitors the ride during operating hours and reports anything that could cause a potential problem.

So the next time you see a ride stop on the lift or the block brake or the back brake there is no reason

Rides are sometimes stopped if a rider is stupid enough to pull out a cellphone.
Want to get hit in the by a phone while flying 85 MPH? I know I don't

to alert the media. The ride is safe and did what it's suppose to do. The guests in the car are just fine and a lot safer than the employees sent up the lift/to the brake area to talk to them. The fire department, the police and 911 aren't needed. The park can handle the situation as they have done the many times it's happened before. A majority of the time it's a minor inconvenience that can be rectified quickly.  Other times it may take some time or require guests to walk off. Park management has procedures and protocols in place for that as well. First Aid in most parks is also trained in how to retrieve guests with disabilities in those situations.

Go ahead, sit back, relax and enjoy the view if you get stuck up on the lift hill or on the brake run but please put your cellphone away. For the love of man please do not call the media, the fire department, 911 or your mother (yes, we know she worries, but you are going to be just fine!)