A monorail traffic corridor is a passage or right-of-way for trains traveling on a single track. This type of train is far less common than conventional two-rail trains, and must be entirely separated from the street grid. Most monorails rest on a fairly wide central guideway, although some hang from an upper rail, and gyroscopically balanced monorails (with a single thin rail similar to a normal train rail) have also been developed as prototypes.

The vehicles can rest on a central guideway or hang below an upper rail. The definition is not limited to one of those arrangements.

The single-rail system is distinct from an ordinary two-rail line operated as a single track. The route retains the stated separation from the street grid.