Racer

The Racer is a wooden racing roller coaster located at the Kennywood amusement park near Pittsburgh in West Mifflin, Pennsylvania, United States. Built by Charlie Mach and designed by John A. Miller, the Racer opened to the public in 1927 and is one of the oldest operating roller coasters in the world.

It features a Möbius loop layout, in which both of its trains travel along one continuous track. Each train returns to the opposite side of the station from which it began.

Source: Wikipedia