page_title: Electric locomotive
section_title: Power transmission
hierarchical_section_title: Electric locomotive / Types / Power transmission
context_page_description: An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor.
  Electric locomotives with on-board fueled prime movers, such as diesel engines or gas turbines, are classed as diesel-electric or gas turbine-electric and not as electric locomotives, because the electric generator/motor combination serves only as a power transmission system.
  Electric locomotives benefit from the high efficiency of electric motors, often above 90%. Additional efficiency can be gained from regenerative braking, which allows kinetic energy to be recovered during braking to put power back on the line. Newer electric locomotives use AC motor-inverter drive systems that provide for regenerative braking. Electric locomotives are quiet compared to diesel locomotives since there is no engine and exhaust noise and less mechanical noise. The lack of reciprocating parts means electric locomotives are easier on the track, reducing track maintenance.
context_section_description: Electrical circuits require two connections (or for three phase AC, three connections). From the beginning, the track was used for one side of the circuit. Unlike model railroads the track normally supplies only one side, the other side(s) of the circuit being provided separately.
caption: A modern half-pantograph
exif: {}