Most coasters with a chain lift have one chain and an anti-rollback device. This safety device is responsible for the "click-clack" noise associated with roller coasters climbing the first hill. A saw-toothed strip of metal on the track interacts with the hinged metal "dogs" that fall from the underside of the cars. These form a linear ratchet that prevents the train from falling backward down the hill.
Tornado has two chains and no anti-rollback teeth. It makes for a silent climb up the lift.
©2014 Joel A. Rogers.