The most unexpected part of the testing was a high speed rollback. The wrong button was pushed so there was no braking. The amount of destruction was impressive. Even so, enough repairs were made for the remainder of the tests to be done the next day.
Rollback test, starting at 4:25
"For the last test that was performed in this series, the main drive shaft that was connecting the gear reducer to the bullwheel was disconnected at the coupling adjacent to the gear reducer. The lift was allowed to travel in reverse with a couple of loaded chairs passing around the bullwheel. It was then instructed that the chairlift be stopped using the bullwheel brake, but since this lift has two stop buttons, the normal stop button was depressed inadvertently instead of the one for the bullwheel brake. Because of this, the lift gained a tremendous amount of speed in the reverse direction, reaching speeds up to 1500 FPM. The 57 pound concrete disk that were placed on the chairs were thrown 120 feet into the air from the center of the bullwheel. Chairs were dislodged from the haul rope and flung in different directions causing them to become tubular steel pretzels after going around the bullwheels. During this rollback, the chairlift traveled 1440 feet or 24 chair lengths resulting in total destruction of the carriers that went around the top and bottom bullwheels. The guidage rails for the top and bottom stations were damaged beyond repair and one carrier managed to get lodged into the lower stations guidage rails. The track rope brake was quickly applied, but because of the speed the lift was traveling and the chairs that were attached to the haul rope, the chairs moved the haul rope out of the track brake. The chairlift eventually slowed down and came to a stop because of the forces of destruction."