What Does It Mean When a Roller Coaster Valleys?

Coaster Round-Up

Hydra The Revenge Cobra Roll Dorney Park Roller Coaster

Roller Coasters are incredibly complicated feats of engineering with many moving parts, but they don't always work well. One of the most common problems with roller coasters is when they valley. But what does that mean.

Valleying, is a term for a specific problem that is one of the most common major problems for many roller coasters.

Typically, vallying occurs when for whatever reason, a roller coaster does not make it to a high point on the track layout. This can be either a hill or the top of an inversion. When the coaster fails to reach this peak, it falls backwards and ends up in the valley of the track.

Thunderbolt Roller Coaster Train at the Bottom of Inversion Coney Island Luna Park

The above picture, although not of a coaster valleying, depicts where a coaster might stop during an incident.

The causes of this issue can vary, and some coasters are more prone to this issue than others. Some common causes include high winds, the coaster being operated at extreme temperatures beyond what it was designed for, or wheel issues.

Most often this issue is not a major problem. People can be evacuated from the ride vehicle and then it is safely relocated to the ride station.

Rarely it can cause serious problems or injuries, but this is usually a result of a combination of problems. A significant incident happened on the roller coaster The Smiler at Alton Towers involving several serious injuries after a ride vehicle valleyed, but this only happened as the safety systems on the ride were erroneously overridden after the incident engaged them.

While it might sound scary, this is a relatively insignificant issue in most incidents that parks plan on happening occasionally on major rides. Even still, it is exceedingly rare and unlikely to happen while you in particular are riding an attraction.