Editing Whyte notation (section)

{{Short description|Code for arrangement of locomotive wheels}}
{{For|the term "white notation" in music|Mensural notation}}
{{Use dmy dates|date=August 2021}}
{{Original research|date=September 2024}}
[[File:Locotypes.gif|thumb|upright|A selection of early 20th century locomotive types according to their Whyte notation and their comparative size]]
[[File:Locomotive classification--Colvin 1906--300dpi.jpg|thumb|upright|Whyte notation from a handbook for railroad industry workers published in 1906<ref name="railroad pocket-book">{{cite book| last=Colvin| first=Fred H.| author-link=Fred H. Colvin| year=1906| title=The railroad pocket-book: a quick reference cyclopedia of railroad information| publisher=New York, Derry-Collard; London, Locomotive Publishing Company (US-UK co-edition)| page=L{{nbhyph}}9 <!-- Not a range --> | url=https://archive.org/details/bub_gb_HhUx85xep4cC }}</ref>]]

The '''Whyte notation''' is a classification method for [[steam locomotives]], and some internal combustion locomotives and [[electric locomotives]], by [[wheel arrangement]]. It was devised by [[Frederick Methvan Whyte]],<ref name="steam glossary" /> and came into use in the early twentieth century following a December 1900 editorial in ''American Engineer and Railroad Journal''.

The notation was adopted and remains in use in North America and the [[United Kingdom]] to describe the wheel arrangements of [[steam locomotive]]s, but for modern [[locomotive]]s, [[multiple unit]]s and [[tram]]s it has been supplanted by the [[UIC classification of locomotive axle arrangements|UIC system]] in Europe and by the [[AAR wheel arrangement|AAR system]] (essentially a simplification of the UIC system) in North America. However, geared steam locomotives do not use the notation. They are classified by their model and their number of trucks.