on the track as the trains ascend the lift-hill. This makes the "clicking" sound and allows the train to go upwards only, effectively preventing the train from rolling back down the hill should it ever encounter a power failure or broken chain. This feature was derived from the similar feature originally used on the Mauch Chunk Switchback Railway in Pennsylvania, starting in 1846. The two uphill planes that cars were drawn up under the power of a stationary steam engine had two slightly different early forms of this anti-rollback device. The entire concept of the modern roller coaster was also initially inspired by this railroad. References Roller coaster elements Roller coaster technology de:Achterbahnelemente#Lifthill