thumb|The ESS 200 electric locomotive was introduced in 1925 in the Dutch East Indies, now Indonesia. An electric locomotive is a locomotive powered only by electricity. Electricity is supplied to moving trains with a (nearly) continuous conductor running along the track that usually takes one of three forms: an overhead line, suspended from poles or towers along the track or from structure or tunnel ceilings; a third rail mounted at track level; or an onboard battery. Both overhead wire and third-rail systems usually use the running rails as the return conductor but some systems use a separate fourth rail for this purpose. The type of electrical power used is either direct current (DC) or alternating current (AC).
thumb|The ESS 200 electric locomotive was introduced in 1925 in the Dutch East Indies now Indonesia An electric locomotive is a locomotive powered only by electricity Electricity is supplied to moving trains with a (nearly) continuous conductor running along the track that usually takes one of three forms an overhead line suspended from poles or towers along the track or from structure or tunnel ceilings; a third rail mounted at track level; or an onboard battery Both overhead wire and third-rail systems usually use the running rails as the return conductor but some systems use a separate fourth rail for this purpose The type of electrical power used is either direct current (DC) or alternating current (AC)