Monorail

A monorail is a form of urban rail transit in which trains run on or are suspended from a single rail or beam, rather than on the paired rails of conventional railways. The word is often used loosely for any elevated railway or people mover, but it refers more exactly to the single-beam track structure. Two main designs exist. In the straddle-beam type the vehicle rides on top of a concrete or steel beam, and in the suspended type it hangs beneath the guideway. The straddle-beam design descends from the ALWEG system of the 1950s and dominates modern installations, while suspended systems such as the Wuppertal Schwebebahn, which opened in 1901 and is the oldest monorail still operating, remain in service. Monorails offer capacity above trams and below heavy metro systems, and they are used in large cities, at airports and in theme parks.