Monorail

A monorail is a railway in which the track consists of a single rail or a beam. Colloquially, the term "monorail" is often used to describe any form of elevated rail or people mover. More accurately, the term refers to the style of track. Monorails are single-rail systems often found in airport transfers and medium-capacity metros. Monorails differ from trams and light rail systems by always being separated from other traffic and pedestrians.

The first monorail prototype was created in Russia in 1820, and since then, various monorail designs have been proposed and implemented. Early monorails used a single metal rail or a gyroscopically balanced system. By the 1950s, monorails adopted larger beam- or girder-based tracks, with ALWEG straddle and SAFEGE systems emerging as popular designs. From the 1980s onwards, Japan became a leader in monorail mass transit, with the Tokyo Monorail being one of the world's busiest systems. China also began developing monorails in the late 2000s, including the world's largest and busiest system in Chongqing. Monorails have since found continued use in shuttle markets, amusement parks, and a growing number of cities using them as modes of mass transit.

Modern monorails rely on a solid beam as the running surface and are divided into two classes: straddle-beam and suspended monorails. Straddle-beam monorails are more common, with trains straddling a steel or reinforced concrete beam. Suspended monorails, like the Wuppertal Schwebebahn in Germany, are less common. Most monorails are powered by electric motors, but diesel-powered systems exist as well. Rubber-tired monorails are designed to handle a 6% grade, and there are mechanisms that allow monorails to switch tracks. Monorails have been featured in popular culture, including movies, television shows, and video games.