according to westcoaster.net...
Some twit had a backpack that they didn't secure and it flew out of the train. The contents got jammed into the wheel bogies and caused the ride to valley! On Saturday they cleared the debris and winched the train up to the block brake. From there they released the train and it successfully finished the course.
so there you go.. backpack jammed the wheels so the train stopped much quicker than it should have.