elevated railways

An elevated railway (also known in Europe as overhead railway) is a rapid transit railway with the tracks above street level on a viaduct or other steel, concrete or brick structure. The railway may be standard gauge, narrow gauge, light rail, monorail or a suspension railway. Elevated railways are usually used in urban areas where there would otherwise be a large number of level crossings. Most of the time, the tracks of elevated railways that run on steel viaducts can be seen from street level.