I jut added this to my to do list. From the Tyrol tourist board site:
Mieders Alpine Coaster, the steepest track in the Alps—it will speed you down to the valley surrounded by the gorgeous mountain scenery of lofty Serles Peak. Those riding the coaster will race along a 2,800 meter track, through the forest, and down the mountain in individual coaster cars. Equipped with rollers and brakes, excitement becomes a reality as you feel the rush of the 640 meter vertical drop. Riders have complete control of their speed (up to 42 kph) for a truly unique, hands-on experience. The alpine coaster makes 40 hairpin turns and is elevated off the ground like a roller coaster.