Editing Rail transport (section)

===Motive power===
[[File:Trains in Napoli Centrale-Garibaldi 18 55 44 221000.jpeg|thumb|An Italian [[InterCity]] electric train at [[Napoli Centrale railway station]]]]
[[Steam locomotive]]s are locomotives with a [[steam engine]] that provides adhesion. [[Coal]], [[petroleum]], or [[wood]] is burned in a [[firebox (steam engine)|firebox]], boiling water in the [[fire-tube boiler|boiler]] to create pressurized steam. The steam travels through the [[smokebox]] before leaving via the chimney or smoke stack. In the process, it powers a [[piston]] that transmits power directly through a [[connecting rod]] (US: main rod) and a [[crankpin]] (US: wristpin) on the [[driving wheel]] (US main driver) or to a [[crankshaft|crank]] on a driving axle. Steam locomotives have been phased out in most parts of the world for economical and safety reasons, although many are preserved in working order by [[heritage railway]]s.

[[Electric locomotive]]s draw power from a stationary source via an [[overhead lines|overhead wire]] or [[third rail]]. Some also or instead use a [[battery (electricity)|battery]]. In locomotives that are powered by high-voltage [[alternating current]], a [[transformer]] in the locomotive converts the high-voltage low-current power to low-voltage high current used in the [[electric motor|traction motors]] that power the wheels. Modern locomotives may use [[Electric motor#Three-phase AC induction motors|three-phase AC induction motors]] or [[direct current]] motors. Under certain conditions, electric locomotives are the most powerful traction.{{citation needed|date=October 2013}} They are also the cheapest to run and provide less noise and no local air pollution.{{citation needed|date=October 2013}} However, they require high capital investments both for the [[overhead lines]] and the supporting infrastructure, as well as the generating station that is needed to produce electricity. Accordingly, electric traction is used on urban systems, lines with high traffic and for high-speed rail.

[[Diesel locomotive]]s use a diesel engine as the [[prime mover (locomotive)|prime mover]]. The energy transmission may be either [[diesel–electric powertrain|diesel–electric]], diesel-mechanical or diesel–hydraulic but diesel–electric is dominant. [[Electro-diesel locomotive]]s are built to run as diesel–electric on unelectrified sections and as electric locomotives on electrified sections.

Alternative methods of motive power include [[maglev (transport)|magnetic levitation]], horse-drawn, [[funicular|cable]], gravity, [[pneumatics]] and [[gas turbine]].