A 4th Dimension roller coaster is a type of steel roller coaster whereby riders are rotated independently of the orientation of the track, generally about a horizontal axis that is perpendicular to the track. The cars do not necessarily need to be fixed to an angle.
John F. Mares, a corporate attorney, invented the 4th Dimension roller coaster concept in 1995 and holds six US patents related to the technology of their spinning seat systems. Three 4D roller coasters: ‘X2,’ ‘Eejanaika,’ and ‘Green Lantern: First Flight,’ which were either built or installed in the United States, have been licensed by Mr. Mares’ company (Meteoro Amusement Corporation).
The first 4th Dimension roller coaster to be built, ‘X,’ which opened at Six Flags Magic Mountain in 2002, was designed and patented by Alan Schilke. 4th Dimension roller coasters are somewhat of a cross between roller coasters and the popular carnival ride known as the Zipper.
Arrow Dynamics was the first company to produce a 4th dimension roller coaster, lending its name to the ride style. The trains feature seats capable of rotating forward or backward, 360 degrees in a controlled spin. This is achieved by having four rails on the track; two acting as per normal, and two to control the spin of the seats. The two rails that control the spin of the seats, known as ‘X Rails,’ vary in height relative to the track, and spin the train using a rack and pinion gear mechanism.
The Intamin ZacSpin was developed in response to the Arrow Dynamics 4th dimension roller coaster. Some of the main differences between the Intamin and Arrow Dynamics/S&S Power versions are the uncontrolled rotation of the seats, which produces a different ride each time, and single cars. Another notable difference is the absence of any lateral movements, causing some enthusiasts to not consider the rides 4th dimension roller coasters due to the fact that all movement is restricted to a 2 dimensional plane.
‘Kirnu’ at Linnanmäki in Helsinki, opened for the 2007 season and was the first of its kind. Later that year ‘Inferno’ opened at Terra Mitica in Spain with an identical compact layout. In 2009, ‘Insane’ opened at Gröna Lund in Stockholm with a different track layout. In 2011, the first ZacSpin in the United States opened at Six Flags Magic Mountain as ‘Green Lantern: First Flight,’ and is themed to the DC Comics superhero of the same name. It features the same layout as ‘Insane.’