Editing Driving wheel (section)

{{Short description|Powered wheel of a locomotive}}
{{About|the powered wheels on locomotives|powered wheels on automobiles|drive wheel|steering control on automobiles known as that in the UK|Steering wheel}}
[[Image:462driving.jpg|thumb|300px|The driving wheels (boxed) on [[Pennsylvania Railroad 1737]]]]
[[Image:Traction motor german-class140.jpg|thumb|300px|Traction motor for a German locomotive]]

On a [[steam locomotive]], a '''driving wheel''' is a powered wheel which is driven by the locomotive's [[piston]]s (or [[turbine]], in the case of a [[steam turbine locomotive]]).<ref>{{cite book| page=37| title=Locomotive Dictionary| edition=1909| first=George L.| last=Fowler| year=1909| publisher=The Railroad Age Gazette| location=New York| url=https://books.google.com/books?id=4rA5AQAAMAAJ&q=locomotive+driving+wheel&pg=PA107| via=Google Books}}</ref> On a conventional, non-articulated locomotive, the driving wheels are all coupled together with side rods (also known as [[coupling rod]]s); normally one pair is directly driven by the [[main rod]] (or [[connecting rod]]) which is connected to the end of the [[piston rod]]; power is transmitted to the others through the side rods.<ref>{{cite book| page=177| title=Catechism of the Locomotive| first=Matthias N.| last=Forney| publisher=The Railroad Gazette| location=New York| year=1879| url=https://books.google.com/books?id=ZkMYAAAAYAAJ&q=locomotive+coupling+rods&pg=PA177| via=Google Books}}</ref><ref>{{cite book| page=560| title=Theory of Machines| edition=second| first=S.S.| last=Rattan| publisher=The McGraw-Hill Publishing Company Ltd.| location=New Delhi, India| year=2006| orig-year=1993| isbn=0-07-059120-2| url=https://books.google.com/books?id=emo4W_VFhEsC&q=locomotive+coupling+rods&pg=PA560| via=Google Books}}</ref><ref>{{cite book| page=382| title=Railway Management and Engineering| edition=third| first=V.A.| last=Profillidis| year=2006| publisher=Ashgate Publishing| location=Aldershot, England, and Burlington, VT, USA| isbn=978-0-7546-4854-3| url=https://books.google.com/books?id=MumsYYDF2xAC&q=locomotive+coupling+rods&pg=PA382| via=Google Books}}</ref>

On [[diesel locomotive|diesel]] and [[electric locomotive]]s, the driving wheels may be directly driven by the [[traction motor]]s. Coupling rods are not usually used, and it is quite common for each axle to have its own motor.  [[Jackshaft (locomotive)|Jackshaft]] drive and coupling rods were used in the past{{sfn|Ransome-Wallis|2001|pages=175-176}}<ref>{{cite book| page=52| title=Internal-Combustion Locomotives and Motor Coaches| first1=Prof. I.| last1=Franco| first2=P.| last2=Labryn| date=11 November 2013| isbn=978-94-017-5765-2| url=https://books.google.com/books?id=E3YPCQAAQBAJ&q=locomotive+coupling+rods&pg=PA52| via=Google Books| publisher=Springer}}</ref> (e.g. in the [[Crocodile (locomotive)|Swiss Crocodile locomotive]]<ref>{{cite book| page=38| title=Electric Traction – Motive Power and Energy Supply| first=Andreas| last=Steimel| publisher=Oldenbourg Industrieverlag GmbH| location=Munich| year=2008| isbn=978-3-8356-3132-8| url=https://books.google.com/books?id=Hdvr82d23mkC&q=locomotive+coupling+rods&pg=PA38| via=Google Books}}</ref>) but their use is now confined to [[Switcher locomotive|shunter locomotives]].

On an [[articulated locomotive]] or a [[duplex locomotive]], driving wheels are grouped into sets with wheels within each set linked together.