Accelerator Coaster

Roller coaster model by Intamin
the Intamin coaster model

An Accelerator Coaster is a hydraulically launched roller coaster model from Intamin. The model usually consists of a long, straight launch track, a top hat tower element, and magnetic brakes that smoothly stop the train without making contact. The technology was developed by Intamin engineers as an alternative to electromagnetic launch systems, such as the Linear Induction Motor (LIM) and Linear Synchronous Motor (LSM), that are found on earlier launched roller coasters like the Flight of Fear and The Joker's Jinx. Unlike the earlier linear induction motors, the Accelerator Coaster's launch system exhibits constant acceleration and is capable of reaching greater speeds. Accelerator Coasters with the top hat element are known to perform an occasional rollback – when the train is unable to complete the top hat element and rolls back to the starting point – which can occur due to a number of different factors. Despite this, Accelerator Coasters have a great track record for safety and are extremely power efficient, especially compared to older technologies such as the classic chain lift found on most roller coasters. Many fans also enjoy the rarity of a rollback. Formula Rossa, the world's fastest coaster, and Kingda Ka, the world's tallest, are some of the most well known installations around the world. Despite these world record setting achievements, Accelerator roller coasters have been infamous for their long terms of mechanical issues with its launch. Examples of these include Xcelerator at Knott's Berry Farm or the former Top Thrill Dragster at Cedar Point and as of 2022, Accelerator Coasters are no longer being produced.

One major advantage of this launch system compared to others is its low power consumption. The hydraulic pumps run constantly and actually use less energy than most chain lift drive motors. An Accelerator Coaster's hydraulic launch system also provides constant acceleration, unlike the acceleration from electromagnetic linear induction motors which begins to decrease or trail off after the initial push.

Most Accelerator Coasters use restraints that consist of a U shaped lap bar that locks into place. The restraint system features an over the shoulder restraint (OTSR) harness designed for comfort and fast loading times. Only three Accelerator Coasters have a lap bar restraint without the over the shoulder harness Xcelerator,

The newer over the shoulder design allows for faster load times, as opposed to lap bars. With lap bar designs, riders must rely on a seat belt around their waist as a backup restraint. It must be checked first by ride attendants before the lap bar can be lowered and checked, significantly slowing load times. In contrast, the over the shoulder restraints are held down with a seatbelt on the outside of the primary restraint. This means that guests can pull down their own restraints and buckle their own belts saving ride attendants time by checking both simultaneously. For trains that have the over the shoulder design, it is possible to swap out the hard, plastic straps that connect the primary bar originally installed to the pivot point with softer cushioned straps.

Most Accelerator Coasters are launched from the station, but there are some that advance the train to a separate launch area, either for theming reasons (Superman Escape) or to allow multiple trains to be loaded simultaneously (Top Thrill Dragster and Kingda Ka). For layouts that have the top hat element, a mechanism is in place to deal with the occasional occurrence of rollbacks where a train fails to pass the peak height of the element and rolls backwards returning to the point of launch. A set of retractable magnetic brakes also found at the final brake run exist on the launch track to stop the train during a rollback.