Editing Locomotive (section)

====Battery–electric====
[[File:Battery loco 16 at West Ham.JPG|thumb|right|A [[London Underground]] battery–electric locomotive used for hauling engineers' trains, at [[West Ham station]]]]
[[File:Wingrove & Rogers 6092.jpg|thumb|right|A narrow-gauge battery–electric locomotive used for mining]]

A battery–electric locomotive (or battery locomotive) is an electric locomotive powered by onboard [[Electric battery|batteries]]; a kind of [[battery electric vehicle]].

Such locomotives are used where a conventional diesel or electric locomotive would be unsuitable. An example is maintenance trains on electrified lines when the electricity supply is turned off. Another use is in industrial facilities where a combustion-powered locomotive (i.e., [[Steam locomotive|steam-]] or [[Diesel locomotive|diesel-]]powered) could cause a safety issue due to the risks of fire, explosion or fumes in a confined space. Battery locomotives are preferred for mines where gas could be ignited by [[Trolley pole|trolley-powered]] units [[Electric arc|arcing]] at the collection shoes, or where [[Electrical resistance and conductance|electrical resistance]] could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground.<ref>{{cite book|last=Strakoš|first=Vladimír|title=Mine Planning and Equipment Selection |year=1997|publisher=Balkema|location=Rotterdam, Netherlands|isbn=90-5410-915-7|page=435|display-authors=etal}}</ref> Battery locomotives in over-the-road service can recharge while absorbing dynamic-braking energy.<ref>{{cite web|last=Lustig|first=David|title=EMD Joule Battery Electric Locomotive arrives in Southern California|url=https://www.trains.com/trn/train-basics/abcs-of-railroading/emd-joule-battery-electric-locomotive-arrives-in-southern-california/|date=21 April 2023|publisher=[[Kalmbach Media]]|work=[[Trains (magazine)|Trains]]|access-date=12 May 2023|archive-date=28 April 2023|archive-url=https://web.archive.org/web/20230428043623/https://www.trains.com/trn/train-basics/abcs-of-railroading/emd-joule-battery-electric-locomotive-arrives-in-southern-california/|url-status=live}}</ref>

The first known electric locomotive was built in 1837 by chemist [[Robert Davidson (inventor)|Robert Davidson]] of [[Aberdeen]], and it was powered by [[galvanic cell]]s (batteries). Davidson later built a larger locomotive named ''Galvani'', exhibited at the [[Royal Scottish Society of Arts]] Exhibition in 1841. The seven-ton vehicle had two [[Direct-drive mechanism|direct-drive]] [[reluctance motor]]s, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simple [[Commutator (electric)|commutators]]. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of {{convert|1+1/2|mi|km|abbr=off|spell=in}}. It was tested on the [[Edinburgh and Glasgow Railway]] in September of the following year, but the limited power from batteries prevented its general use.<ref>{{cite book|last1=Day|first1=Lance|last2=McNeil|first2=Ian|title=Biographical dictionary of the history of technology|year=1966|publisher=Routledge|location=London|isbn=978-0-415-06042-4|chapter=Davidson, Robert|url=https://archive.org/details/isbn_9780415060424}}</ref><ref>{{cite book|last=Gordon|first=William|title=Our Home Railways|publisher=Frederick Warne and Co|location=London|year=1910|volume=2|page=156|chapter=The Underground Electric}}</ref><ref name="ReferenceA">Renzo Pocaterra, ''Treni'', De Agostini, 2003</ref>

Another example was at the [[Kennecott, Alaska|Kennecott Copper Mine]], [[Latouche, Alaska]], where in 1917 the underground haulage ways were widened to enable working by two battery locomotives of {{frac|4|1|2}} tons.<ref>{{cite book|last=Martin|first=George Curtis|title=Mineral resources of Alaska|url=https://archive.org/details/mineralresource01sgoog|year=1919|publisher=Government Printing Office|location=Washington, DC|page=[https://archive.org/details/mineralresource01sgoog/page/n156 144]}}</ref> In 1928, Kennecott Copper ordered four 700-series electric locomotives with on-board batteries. These locomotives weighed 85 tons and operated on 750-volt overhead trolley wire with considerable further range whilst running on batteries.<ref>{{Cite web|url=http://utahrails.net/bingham/kcc-diesel-elec-loco.php#700-elec|title=List of Kennecott Copper locomotives|access-date=2 December 2017|archive-date=6 March 2012|archive-url=https://web.archive.org/web/20120306040601/http://utahrails.net/bingham/kcc-diesel-elec-loco.php#700-elec|url-status=dead}}</ref> The locomotives provided several decades of service using [[Nickel–iron battery]] (Edison) technology. The batteries were replaced with [[Lead–acid battery|lead-acid batteries]], and the locomotives were retired shortly afterward. All four locomotives were donated to museums, but one was scrapped. The others can be seen at the [[Boone and Scenic Valley Railroad]], Iowa, and at the [[Western Railway Museum]] in Rio Vista, California. The [[Toronto Transit Commission]] previously operated a battery electric locomotive built by [[Nippon Sharyo]] in 1968 and retired in 2009.<ref>{{Cite web | url=http://transittoronto.ca/subway/5510.shtml | title=A Rogue's Gallery: The TTC's Subway Work Car Fleet – Transit Toronto – Content | access-date=16 March 2020 | archive-date=27 April 2021 | archive-url=https://web.archive.org/web/20210427041014/http://transittoronto.ca/subway/5510.shtml | url-status=live }}</ref>

London Underground regularly operates [[London Underground battery–electric locomotives|battery–electric locomotives]] for general maintenance work.