As modern, electrically-powered trains, elevated rail systems make relatively efficient use of electrical power provided through electrical distribution systems and grids. While environmentally superior to diesel and other fuel-burning locomotives, the relatively heavy train vehicles of elevated rail systems consume significant levels of electrical power in their normal operation. Significant reduction in electrical power consumption could be achieved only through a substantial reduction in the weight, or mass of the rail vehicles operating on elevated rails. Development of entirely new forms of propulsion or mechanical characteristics are not likely to take place on the steel-wheel, steel rail trains characteristic of new and old elevated rail systems.
The only fundamental changes in the mechanical and propulsion systems of elevated trains currently operational are in the form of magnetic levitation and monorail systems, which do not operate on steel rails. Elevated sections of high-speed trains share a similar energy consumption profile with at grade and subway steel-wheel, steel rail trains.
