Fourth-dimension roller coaster
| Fourth-dimension roller coaster | |
|---|---|
| 'X2' (formerly 'X') was the first fourth-dimension roller coaster in the world. | |
| Status | In production | 
| First manufactured | 2002 | 
| No. of installations | 18 | 
| Manufacturers | Arrow Dynamics (discontinued), S&S Worldwide, and Intamin | 
| Riders per row | 4 | 
| Restraint Style | Over-the-shoulder | 
A fourth-dimension roller coaster is a type of steel roller coaster where riders are rotated independently of the track's orientation about a horizontal axis perpendicular to the track. This feature allows riders to experience inversions without the track rotating upside down. Some fourth-dimension roller coasters are controlled, with seats that rotate based on the spacing of two additional rails on the track. Others are free-spinning, where the seats flip primarily due to forces exerted by the ride's elements, offering a different experience during each ride.