at Tojoko land. After debuted improved type model built named loop the loop built at few amusement park in Japan , and variant model:Moonsault Scramble. Meisho's model used catch car lift , pulls to the top and dropping backward through the station into the single vertical loop and traveled up opposite side hill, through the loop, and into the station. In 1980 Senyo Kogyo debuted Atomic coaster at Mitsui green land. Senyo model used chain lift , pulls to the flat top and dropping backward through the station and second downhill , through the low single vertical loop. Vekoma's Boomerang In 1984 Vekoma debuted its Boomerang shuttle coaster, which features a lift hill rather than a launched train. In addition to the original Boomerang, Vekoma also designed the Invertigo and the Giant Inverted Boomerang. As of 2018, 55 Boomerangs and its variants are currently in operation around the world. Linear motor launched shuttle coasters In 1996 Premier Rides debuted the first coasters ever to use linear induction motors, and in 1997 opened Batman & Robin: The Chiller at Six Flags Great Adventure, a pair of dueling launched shuttle coasters. Intamin introduced its reverse freefall coaster in 1997. In these models, the train is accelerated out of the station along a long, level track using linear synchronous motors, rises straight up a vertical tower, then free falls back down to return to the station. Only two reverse freefall coasters were built: Tower of Terror II at Dreamworld, and Superman: Escape from Krypton at Six Flags Magic Mountain, both of which first broke the 300 foot and 400 foot barriers. Tower of Terror II, however, discontinued in 2019. In 1998, Intamin introduced its first impulse coaster, Linear Gale at Korakuen Amusement Park in Japan, which featured inverted trains traversing two vertical towers. In 2000, Intamin introduced Superman Ultimate Escape with a spiral tower and one vertical tower. Intamin introduced Wicked Twister in 2002, a variation with two spiral towers. With each pass through the station the train accelerates faster and travels further up the towers. The first modern wooden shuttle coaster, Switchback, opened at ZDT's Amusement Park in 2015. Manufactured by The Gravity Group, the ride utilizes a traditional lift hill like most wooden coasters but ends on a tower before traversing the course backwards and returning to the station via a switch track. See also Shuttle Loop — shuttle coasters manufactured