Monorail

Railway with a single rail or beam

A monorail is a railway in which the track consists of a single rail or 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. Monorail systems are most frequently implemented in large cities, airports, and theme parks.

This keyword could refer to multiple things. Here are some suggestions: