The original Switchback Railway at Coney Island was the first roller coaster designed as an amusement ride in America. It was designed by LaMarcus Adna Thompson in 1881 and constructed in 1884. It appears Thompson based his design, at least in part, on the Mauch Chunk Switchback Railway which was a coal-mining train that had started carrying passengers as a thrill ride in 1827.
For five cents, riders would climb a tower to board the large bench-like car and were pushed off to coast 600 ft (183 m) down the track to another tower. The car went just over 6 mph (9.7 km/h). At the top of the other tower the vehicle was switched to a return track or “switched back” (hence the name.) [...]
[via The Retronaut]