The Theme Park Automation Crisis

As technology advances, and we find new innovative ways to entertain our guest, we often forget about the systems that are already in place. Its simply that most of the time those older systems work, and if it isn’t broke than why fix it? To the average theme park patron they see a ride, they see something that provides entertainment to them. As they board the ride, an ominous feeling overwhelms them, knowing they are going to return safely from their journey. It is very well known fact that statistically you have a higher chance of dieing in a plane crash, than being killed on an amusement ride. The advancements over the years have helped to provide an even safer ride for our guest. These advancements aren’t perfect tho.

There is no substitute for good experienced operators, mechanical backups, and a solid maintenance plan. A computer system cannot monitor all the variables which which may lead to an accident. For example, On June 22nd 2008 at Six Flags Kentucky Kingdom, a 13 year old girls legs where severed when a cable on the ride snapped. In a statement from the attendant of the ride, she said that she “heard something snap”, and than told then main operator to press the E-stop. The computer would not have given any indication that the cable was about to fail, and unless the operators where watching the ride it is hard to tell if there could have been any other out come from this tragic event. Superman Tower of Power, has since been removed from the park.

The systems that power these rides are very basic in nature, they are custom tailored to each ride & park needs. The programmable logic controller, or PLC, is the rides brain. It is connected to an input and output system that takes information from the various sensors and process’s it. On the input side of the system you may have proxy switches, photo eyes, laser counters, switches, and push buttons. The output side is attached to the braking relay system, the block or zoning system, air gates, the lights for the push buttons and switches. Its impossible for me to list all the possible things, so keep in mind this just a small list. A human has to program the system, humans make mistakes. While these systems can sometimes have redundancy, often times they don’t. If a component fails, it can give the system bad information. Unless there is an redundant error checking function built into the system the computer can only act with the information it receives.

One summer I was working maintenance for a local theme park, and we got a call for a ride down with an E-stop. Upon reaching the ride we found it in the up position, moving slowly in the wrong direction of travel. The E-Stop light is clearly solid, So I perform a power disconnect so I can manually lower the ride by dumping the hydraulics. Its probably 108 on this day, AC isn’t working in the computer room and by now I can tell its going to be one of those days. Unload the guest off the ride, bring pressure back into the hydraulics, and restore power to the ride. As soon as powers restored, ride is once again running backwards slowly lifting back up. That E-Stop is still as red as ever, So I pull the E stop out and work to clear it from the computer. Ride goes nuts, spinning backwards, going up and down, all lights on the panel flashing. !-Smack-! – E-stop has been pressed again.

I disconnect the power again and adventure into the computer room, this system was a dinosaur by today’s standards. After an hour I called for help, and it came with a simple solution to a common problem. Replace the ram card. When the RAM failed on this machine, the computer defaulted to pulsing certain outputs to indicate system trouble. It just so happened that those outputs where connected to the hydraulics and the electric motor. While that system was a dinosaur, ten years later not much has changed in the way that control system is setup.

Newer rides I worked on in the late nineties had redundant systems, but they required at certain points to offload data to a desktop computer and which is then fed back into the system. Doesn’t it defeat the purpose of having redundancy if your one source of failure is an aging Pentium one desktop running windows 95 which handles cross checks and error handling. Lets be a little realistic here, 95 was a somewhat stable system for the time, but now we have much more stable choices to choose from. Can’t we upgrade? Of course we can, but because it cost so much to do it parks won’t, unless they have to. Because if it ain’t broke don’t fix it. You have often heard me say that a rides fate is often decided when its operation worth is less than the cost to keep it running. There have been some great rides that where sound mechanically, but needed to have a electrical overhaul. What a waste of a perfectly good ride, rusting away in a field until scrap prices go up.

This is a big problem for our industry, While it doesn’t effect every ride at every park, the rides it does affect could turn into a serious problem down the road. We need to work to fix the gaps in our control systems, and to develop policies that promote an operator first line of defense against computer faults. Even tho our operators may only be 16 years of age, they are smart enough to know what the ride should and should not be doing. It comes with the experience of operating a ride for hours on end. Management is often so fixated on ride uptime that they punish there best operators for stopping the operation of a ride to investigate a problem. God forbid ride downtime on paper be a little high because an operator found something wrong. I have never disciplined an operator for stopping a ride as a safety precaution, But that doesn’t stop others from doing it. Computers don’t know when a guest is having a heart attack, or if the wheels are loose, or if that third rack on the restraint is worn out.