Coasters-101: Daily Inspections
If you’re a frequent visitor of amusement parks you are probably aware that the roller coasters are inspected on a daily basis in order to ensure the rides run safely. But what does an inspection entail? The goal of an inspection is to prevent accidents. If maintenance personnel find something dangerous they are going to close the ride, whether it’s for a few minutes or a few days. Preventive maintenance is extremely important when it comes to thrill rides. There are a multitude of tasks that need to be performed on each area of the ride to keep it maintained and in great running condition.
First, before any inspections occur the ride must be locked out. This is extremely important for safety of the workers. There have been too many incidents in the amusement industry where a ride has been started with workers in dangerous areas leading to unfortunate accidents. (See one of our previous articles for more information about lock out tag out procedures).
A roller coaster’s track is typically inspected every day before the park opens, at the request of management during the day, or due to an accident or near accident. Maintenance personnel will visually inspect high stress areas, such as the bottom of a big drop or the underside of the rails of airtime filled hills. Before the coaster can be ran safely the track must be free of obstructions, such as tree limbs or litter which might have fallen on the rails during the night or after a strong storm. All the welds on handrails, stairs, and, catwalks are examined for cracks.
Some rides require booster tires to move the trains from one block zone to another. These tires must be properly maintained and inspected for proper inflation and wear. This may include keeping the tire pressure at a specific level, such as 50 pounds per square inch.
There are several items to check on the lift hill including: chain dampeners, anti-rollback on gearbox, sprocket and intermediate chain, chain trough, chain and chain tension. In the station and queue areas the station air gates should be checked for proper alignment. All buttons and lights on the operator’s panel should be working correctly. Transfer tracks should be locked in place. Brake shoes should be checked for excessive wear and proper alignment.
Now, let’s look at the vehicles. The exact tasks vary from one coaster to another but typical daily inspections on the roller coaster cars include: Inspecting the restraint system for proper operation, inspect condition of upholstery, condition of fiberglass, hitch yokes, safety cables, wheels for rotation, damaged urethane and proper oil level, castle nuts securing wheels, chain dogs, anti roll back dogs, and shafts, axle center spindle for looseness, undercarriage of trains for cracks and missing safety wire for nuts. Excessive grease may need to be cleaned from each of the cars.
Before the ride can open to the public it must be cycled a certain number of times. The E-stop or emergency stop must be checked for the proper operation of the ride. This may include bringing the coaster’s train to a complete stop on each of the ride’s brake sections of track. After a visual inspection, the maintenance crew runs the roller coaster empty of passengers, watching and listening for any abnormalities. Then the crew may get on for their own ride, this time paying attention to anything in the feel and the sound of the ride that seems out of sync. The roller coaster is open to the public only after a complete inspection of the cars, lap bars, and tracks that can take up to four hours or longer.
The number of technicians inspecting each ride really varies on the size and complexity of the ride. A larger roller coaster will obviously take more time and personnel to inspect versus a kiddie ride. Different technicians have different job responsibilities, such as a mechanical, carpenter, electrical, fiberglass, etc.
Ride components are checked for any signs of wear and often need replacing. There are two common terms when it comes to repairs. MTBF stands for the mean time between failure, or the average time between breakdowns of a ride or component. Ideally, this amount of time would be large as possible, like weeks or months or even years. If the ride does break down then we need to consider MTTR which stands for the mean time to repair or the average amount of time it takes to fix a ride. Remember this (from Steve Alcorn’s Theme Park Design : “If it ain’t broke, don’t fix it. But if it is broke, it better be fixable in one night.”
These are just some of the tasks that need to be done on a daily basis to keep an attraction properly maintained and running safely. There are other tasks that take place on a weekly, monthly, and annual basis. At least once per year, most parks X-ray their track or use magnetic scanners to check for metal stress or welds that need attention. Also, all vehicles are completely disassembled, inspected, and rebuilt at least once a year. Inspection schedules also vary between seasonal parks and parks open all year long. But that is a topic for another day. Stay tuned for the next session of Coasters-101!
To learn more about how coasters are designed check out Coasters 101: An Engineer’s Guide to Roller Coaster Design.