Capacity optimization

Journey into Themed Design

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Capacity optimization

You could have the best ride in the world, your satisfaction rate will never rise if you can’t absorb the guests at a reasonable rate. In order to increase the flow, a lot of techniques are often used. Here are a few examples :

A good scene-cutting

In rail-guided rides, or even in dark-rides (let’s ignore the omni-movers), the number of simultaneous vehicles depends on the layout of the scenes.

In a rollercoaster, the ride is divided in zones. Each zone has an emergency-brake allowing to completely stop the train before it gets to the next zone. A train can move only if the next zone is free, which means there are no vehicles inside. The number of trains you can use in theory is « Number of zones – 1 ». In reality, these conditions would cause a lot of technical problems (called « intrusion » : a train tried to enter an occupied zone) and we’d rather have a margin to ease the operations. For example, Big Thunder Mountain in California is divided in 8 zones, but allows a maximum of 5 trains.

Brake zone from « Gate Keeper ». Credit : NewsPlusNotes

In a more story-driven ride, the cutting will be done regarding the scenes, in the true meaning of term. We will therefore not allow two vehicles or clusters to be in the same picture at the same time

  • Firstly for immersion ! Tough to feel like an adventurer if there are 24 people experiencing all the surprises right before you.
  • For technical reasons : some special effects have to be resetted to function.

That’s why the layouts are often tortuous : it allows to isolate the scene between them. Try to count the number of turns and U-Turns in Indiana Jones adventure… and this particular attraction sometimes have vehicles crossing each other!


As you can see in the blueprint above, borrowed from, the loading scene is separated from the scene 1 (Chamber of Destiny), itself separated from the next scene by an automatic door.

The difficulty is that the scenes have to be the same length to avoid creating a backup… (except if you create the same scene in double, like in Ratatouille). This constraint is the origin of one of the most famous special effects of theme parks : the boulder scene! Interlude!


Indiana Jones Adventure – Boulder Scene

Put yourself in the shoes of an Imagineer for a moment : impossible to picture a 5 minutes Indiana Jones ride without a giant boulder straight from Raiders of the Lost Ark coming right to your vehicle! However, in this situation, anyone would put the reverse gear to avoid a certain death. Here is the sequence you could imagine : 

1 – Face to face with the boulder

2- The boulder is coming at you, you go backward

3- You go frontward again to take the hidden way right under the boulder

You’ve just made a major hit to your ride capacity. The backtracking of your vehicule and his second move frontward will take a time you cannot allow yourself without creating a backup. Moreover, you will need to keep a long distance with the car behind to be able to move back without entering its field of view… Can we move back… without moving back?

Seems possible. Legend says the idea comes directrly from Tony Baxter, Vice-President at Walt Disney Imagineering back in the time. Good ol’ Tony was going to get his car clean at the automatic carwash. He stops his car, pull the handbrake, and wait for the machine to clean his car. At the moment the carwash advances to his vehicle, Tony thinks for a brief second that it’s his own vehicle which is moving. The brain is so much conditionned to think that « the car moves, the scenery doesn’t » that the reverse
hypothesis comes second. That’s exactly the principle used in the attraction.

1 – Face to face with the boulder

2- The bolder comes toward you… The car leans to the front, with the right sound effects of tire scratching. Passengers are retained only by their seatbelt. The walls move forward to create a scrolling illusion. The magic is happening

3- The vehicle moves forward and take the hidden way right under the boulder.

You’ve won a direction switch, distance traveled, and precious second to save your capacity!




Let’s be a little more technical now. Each ride is conceived with a Theoretical Hourly  Ride Capacity (THRC). This number means the number of guests who can ride the attraction each hour in perfect theoretical condition : no empty seats (Hello, single rider liner!), all vehicles available, and operators as fast as rockets. 

The calculation is fast

THRC = 3600 / dispatch time, both numbers in seconds.

The dispatch time is the minimum time you have to wait between two vehicles dispatch. It is the maximum value between the longuest scene and the time in station. The time in station is : Time for the train to park + time to unload passengers+ time to load + time for the train to leave the station.

When a ride has two parallel stations, this time is divided by two. 

The number of simultaneous vehicles comes from this data : you just need enough to have one available when the dispatch time is over.

Picture from