Monorail

A monorail is a railway in which the track consists of a single rail or a beam. The term is also used to describe the beam of the system, or the trains traveling on such a beam or track. The term originates from joining "mono" and "rail" from 1897, possibly from German engineer Eugen Langen, who called an elevated railway system with wagons suspended the Eugen Langen One-railed Suspension Tramway.