It's not only Disney which use backstories in their attractions. Here's my first non-Disney backstory for the collection, written for the Nemesis inverted roller coaster at Alton Towers Theme Park, England.
Nemesis comes from another dimension, a dimension beyond our imagination. There are theories, and then there is the legend... Beneath the ground at Alton Towers something strange and horrible lurked: a creature put on the Earth 2 million years ago. The creature was disturbed during maintenance work on one of the other rides in Forbidden Valley. The creature, angry at being discovered, caused havoc, ripping up trees and buildings sending them hurtling skyward. A security silence fell over Alton Towers as historians, archaeologists and the Ministry of Defence nervously began some serious investigations. What they discovered was Nemesis. It had to be controlled - 250 tonnes of steel and 200 men pinned down Nemesis. The steel holding down the monster was twisted and bent into unusual shapes - the steel was the roller coaster track thrill seekers ride today - Nemesis.