Complex sentence: It operated under that name until the end of the 2007 season when the park closed the ride indefinitely, and the Gerstlauer trains were relocated to Six Flags St. Louis to be used as spare parts for The Boss, another Custom Coasters International ride with Gerstlauer trains.
Split into simpler sentences: It operated under that name until the end of the 2007 season when the park closed the ride indefinitely. Although standing but not operating, the Gerstlauer trains were relocated to Six Flags St. Louis to be used as spare parts for The Boss, another Custom Coasters International ride with Gerstlauer trains.