View source for Whyte notation

{{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.

== Structure of the system ==
=== Basic form ===
The notation in its basic form counts the number of [[leading wheels]], then the number of [[driving wheels]], and finally the number of [[trailing wheels]], numbers being separated by dashes.<ref>{{cite web| url=http://www.trains.com/trn/default.aspx?c=a&id=201| title=Builder's plates: A locomotive's birth certificate| publisher=[[Kalmbach Publishing]]| author=Thompson, Keith| date=2006-05-01| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20081122011919/http://www.trains.com/trn/default.aspx?c=a&id=201| archive-date=22 November 2008}}</ref> For example, a locomotive with two leading axles (four wheels) in front, then three driving axles (six wheels) and then one trailing axle (two wheels) is classified as a {{whyte|4-6-2}} locomotive, and is commonly known as a ''Pacific''.

=== Denotion of other locomotives ===
=== Articulated locomotives ===
For [[articulated locomotives]] that have two wheelsets, such as [[Garratt locomotive|Garratt]]s, which are effectively two locomotives joined by a common [[boiler]], each wheelset is denoted separately, with a plus sign (+) between them. Thus a 4-6-2-type Garratt is a {{whyte|4-6-2+2-6-4}}. For Garratt locomotives, the plus sign is used even when there are no intermediate unpowered wheels, e.g. the [[LMS Garratt]] {{whyte|2-6-0+0-6-2}}.  This is because the two engine units are more than just [[power bogie]]s. They are complete engines, carrying fuel and water tanks. The plus sign represents the bridge (carrying the boiler) that links the two engines.

Simpler articulated types, such as [[Mallet locomotive|Mallet]]s, have a jointed frame under a common boiler where there are no unpowered wheels between the sets of powered wheels. Typically, the forward frame is free to swing, whereas the rear frame is rigid with the boiler. Thus, a [[Union Pacific Big Boy]] is a {{whyte|4-8-8-4}}: four leading wheels, one group of eight driving wheels, another group of eight driving wheels, and then four trailing wheels. Sometimes articulated locomotives of this type are denoted with a “+” between each driving wheels set (so in the previous case, the Big Boy would be a 4-8+8-4). This may have been developed to distinguish articulated and duplex arrangements; duplex arrangements would get a “-“ being rigid and articulated locomotives would get a “+” being flexible. However, given all the wheel arrangements for duplex locomotives have been mutually exclusive to them, it is usually considered unnecessary and thus another “-“ is usually used.

[[Triplex locomotive]]s, and any theoretical larger ones, simply expand on basic articulated locomotives, for example, [[2-8-8-8-2]]. In the case of the Belgian [[quadruplex locomotive]], the arrangement is listed as 0-6-2+2-4-2-4-2+2-6-0.<ref>{{cite web | url=http://www.douglas-self.com/MUSEUM/LOCOLOCO/francocrosti/francocrosti.htm#b | title=The Franco-Crosti Boiler System }}</ref>

=== Duplex locomotives ===
For [[duplex locomotive]]s, which have two sets of coupled driving wheels mounted rigidly on the same frame, the same method is used as for [[Mallet (locomotive)|Mallet]] [[#Articulated locomotives|articulated locomotives]] – the number of leading wheels is placed first, followed by the leading set of driving wheels, followed by the trailing set of driving wheels, followed by the trailing wheels, each number being separated by a hyphen.

=== Tank locomotives ===
A number of standard suffixes can be used to extend the Whyte notation for [[tank locomotives]]:<ref name=irs>{{irs-el|el=17}}</ref>

{|class="wikitable"
!Suffix
!Meaning
!Example
|-
|[No Suffix]
|[[Tender locomotive]]
|{{whyte|0-6-0}}
|-
|T
|[[Tank locomotive]]
|{{whyte|0-6-2|T}}
|-
|ST
|[[Saddle tank locomotive]]
|{{whyte|0-4-0|ST}}
|-
|WT
|[[Well tank locomotive]]
|{{whyte|0-4-0|WT}}
|-
|PT
|[[Pannier tank locomotive]]
|{{whyte|0-6-0|PT}}
|-
|C or CT
|[[Crane tank locomotive]]
|{{whyte|0-6-2|CT}}
|-
|IST
|[[Inverted saddle tank locomotive]]
|{{whyte|0-4-2|IST}}
|-
|T+T (or ST+T, WT+T, etc.)
|[[Tank locomotive#Tender-tank|Tender-tank locomotive]]
|{{whyte|0-4-0|T|T}}
|-
|WT
|[[Tank locomotive#Wing tank|Wing tank locomotive]]
|[[0-4-0]][[Tank locomotive#Wing tank|WT]]
|-
|RT
|[[Tank locomotive#Rear tank|Rear tank locomotive]]
|[[0-4-4T|0-4-4]][[Tank locomotive#Rear tank|RT]]
|}

=== Other steam locomotives ===
Various other types of steam locomotive can be also denoted through suffixes:<ref name=irs/>
{|class=wikitable
|colspan=2|VB or VBT
|[[Vertical boilered locomotive]]
|{{whyte|0-6-0|VB}}
|-
|colspan=2|F
|[[Fireless locomotive]]
|{{whyte|0-6-0|F}}
|-
|colspan=2|CA
|[[Compressed air locomotive]]
|{{whyte|0-6-0|CA}}
|-
|colspan=2|R
|[[Railcar]]
|{{whyte|0-4-4-0|R}}
|-
|colspan=2|R or RT
|[[Rack locomotive]]
|{{whyte|0-4-0|RT}}
|}

=== Internal combustion locomotives ===
{{redirect|8w (locomotive)||8W (disambiguation)#Rail transport}}
The wheel arrangement of small [[Diesel locomotive|diesel]] and [[Petrol locomotive|petrol]] locomotives can be classified using the same notation as steam locomotives, e.g. 0-4-0, 0-6-0, 0-8-0. Where the axles are coupled by chains or shafts (rather than side rods) or are individually driven, the terms 4w (4-''wheeled''), 6w (6-wheeled) or 8w (8-wheeled) are generally used. For larger locomotives, the [[UIC classification]] is more commonly used.

Various suffixes are also used to denote the different types of internal combustion locomotives:<ref name=irs/>
{|class=wikitable
!Suffix
!Meaning
!Example
|-
|PM
|[[Petrol-mechanical locomotive]]
|{{whyte|4w|PM}}
|-
|PE
|[[Petrol-electric locomotive]]
|{{whyte|0-6-0|PE}}
|-
|D
|[[Diesel locomotive]]
|{{whyte|6w|D}}
|-
|DM
|[[Diesel–mechanical locomotive]]
|{{whyte|8w|DM}}
|-
|DE
|[[Diesel–electric locomotive]]
|{{whyte|0-4-0|DE}}
|-
|DH
|[[Diesel–hydraulic locomotive]]
|{{whyte|0-6-0|DH}}
|}

=== Electric locomotives ===
The wheel arrangement of small [[electric locomotive]]s can be denoted using this notation, like with [[#Internal combustion locomotives|internal combustion locomotives]].

Suffixes used for electric locomotives include:
{|class=wikitable
!Suffix
!Meaning
!Example
|-
|BE
|[[Battery-electric locomotive]]
|{{whyte|4w|BE}}
|-
|OE
|[[Electric locomotive#Overhead lines|Overhead-lines electric locomotive]]
|{{whyte|0-8-0|OE}}
|-
|RE
|[[Third rail|Third rail electric locomotive]]
|{{whyte|4w|RE}}
|}

== {{anchor|Naming}}Wheel arrangement names ==
In American (and to a lesser extent British) practice, most wheel arrangements in common use were given names, sometimes from the name of the first such locomotive built. For example, the [[2-2-0]] type arrangement is named ''Planet'', after [[Planet (locomotive)|the 1830 locomotive]] on which it was first used. (This naming convention is similar to the naming of warship classes.) Note that several wheel arrangements had multiple names, and some names were only used in some countries.

Wheel arrangements under the Whyte system are listed below. In the diagrams, the front of the locomotive is to the left.
{| class="wikitable"
! Arrangement<br />(locomotive front is to the left) !! Whyte classification !! Name !! No. of units produced
|-
| colspan="4" |
|-
! colspan="4" | Non-articulated locomotives
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-2-2.svg|27px]] || [[0-2-2]] || Northumbrian (after the  [[Northumbrian (locomotive)|1830 locomotive ''Northumbrian'']])
|-
| || [[0-2-4]] || 
|-
| [[File:WheelArrangement 2-2-0.svg|30px]] || [[2-2-0]] || Planet
|-
| [[File:WheelArrangement 2-2-2.svg|35px]] || [[2-2-2]] || Single,<ref name="steam glossary" /> Jenny Lind<ref name=":2">{{Cite book |title=Directory of Railway Officials & Year Book 1956-1957 |publisher=Tothill Press Limited |year=1956 |location=London |pages=421}}</ref>
|-
| [[File:WheelArrangement 2-2-4.svg|45px]] || [[2-2-4T|2-2-4]] || Aerolite
|-
| [[File:WheelArrangement 4-2-0.svg|40px]] || [[4-2-0]] || Jervis<ref>{{cite book| title=A History of the American Locomotive - Its Development: 1830-1880| author=White, John H. Jr.| publisher=Dover Publications| location=New York| year=1968| isbn=0-486-23818-0 }}, p. 33.</ref>
|-
| [[File:WheelArrangement 4-2-2.svg|50px]] || [[4-2-2]] || Bicycle<ref name=":2" />
|-
| [[File:WheelArrangement 4-2-4.svg|55px]] || [[4-2-4T|4-2-4]] || Huntington
|-
| [[File:WheelArrangement 6-2-0.svg|50px]] || [[6-2-0]] || [[Crampton locomotive|Crampton]]<ref>{{cite journal| journal=NMRA Bulletin| publisher=National Model Railroad Association| title=The Crampton Type Locomotive on the Camden & Amboy Railroad|date=December 1968| author=Adams, Bob }}</ref>
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-4-0.svg|35px]] || [[0-4-0]] || Four-wheel switch<ref name=":2" />
|-
| [[File:WheelArrangement 0-4-4.svg|35px]] || [[0-4-0+4]] || 
|-
| [[File:WheelArrangement 0-4-2.svg|45px]] || [[0-4-2]] || Olomana
|-
| [[File:WheelArrangement 0-4-4.svg|55px]] || [[0-4-4T|0-4-4]] || Forney<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 2-4-0.svg|45px]] || [[2-4-0]] || Porter, 'Old English'<ref>Ellis, C Hamilton, ''Some Classic Locomotives'', Allen & Unwin, 1949.173 p.</ref>
|-
| [[File:WheelArrangement 2-4-2.svg|60px]] || [[2-4-2]] || Columbia<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 2-4-4.svg|65px]] || [[2-4-4T|2-4-4]] || Forney, Mason Bogie
|-
| [[File:WheelArrangement 4-4-0.svg|60px]] || [[4-4-0]] || American,<ref name="railroad pocket-book" /><ref>White (1968), p. 46.</ref> eight-wheeler
|-
| [[File:WheelArrangement 4-4-2.svg|70px]] || [[4-4-2 (locomotive)|4-4-2]] || Atlantic<ref name="railroad pocket-book" /><ref>{{cite encyclopedia| author=Marsden, Richard| url=http://www.lner.info/locos/C/c.shtml| title=The LNER 4-4-2 Atlantic Locomotives| encyclopedia=The London & North Eastern Railway (LNER) Encyclopedia| year=2008| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20080213172111/http://www.lner.info/locos/C/c.shtml| archive-date=13 February 2008}}</ref>
|-
| [[File:WheelArrangement 4-4-4.svg|75px]] || [[4-4-4]] || Reading, Jubilee (Canada)<ref>{{cite web| url=http://www.cr.nps.gov/history/online_books/steamtown/shs3h.htm| title=Canadian Pacific Railway No. 2929| work=Steamtown NHS Special History Study| publisher=United States National Park Service| date=2002-02-14| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20070519064257/http://www.cr.nps.gov/history/online_books/steamtown/shs3h.htm| archive-date=19 May 2007}}</ref>
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-6-0.svg|55px]] || [[0-3-0]]<!--this is correct-->||(one driving wheel per axle; used on [[Patiala State Monorail Trainways]] and also on the [[Listowel and Ballybunion Railway]])
|-
| [[File:WheelArrangement 0-6-0.svg|55px]] || [[0-6-0]] || Six-coupled,<ref name="railroad pocket-book" /> Six-wheel switch,<ref name=":2" /> Bourbonnais (France - tender), Boer (France - tank)
|-
| [[File:WheelArrangement 0-6-2.svg|65px]] || [[0-6-2]] ||Branchliner, Webb 
|-
| [[File:WheelArrangement 0-6-4.svg|75px]] || [[0-6-4]] || Forney six-coupled<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 0-6-6.svg|75px]] || [[0-6-6]] || Forney six-coupled
|-
| [[File:WheelArrangement 2-6-0.svg|70px]] || [[2-6-0]] || Mogul<ref name="railroad pocket-book" /><ref>White (1968), p 62-65.</ref> || 11,000
|-
| [[File:WheelArrangement 2-6-2.svg|75px]] || [[2-6-2]] || Prairie<ref name="railroad pocket-book" /><ref name="steam glossary" />
|-
| [[File:WheelArrangement 2-6-4.svg|80px]] || [[2-6-4]] || Adriatic<ref name=":2" />
|-
| [[File:WheelArrangement 2-6-6.svg|85px]] || [[2-6-6]] || Mason Bogie
|-
| [[File:WheelArrangement 4-6-0.svg|75px]] || [[4-6-0]] || Ten-wheeler<ref name="railroad pocket-book" /><ref>White (1968), p. 57.</ref> (not Britain)<ref>{{cite encyclopedia| author=Marsden, Richard| url=http://www.lner.info/locos/B/b.shtml| title=LNER 4-6-0 Locomotives| encyclopedia=The London & North Eastern Railway (LNER) Encyclopedia| year=2008| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20080213191949/http://www.lner.info/locos/B/b.shtml| archive-date=13 February 2008}}</ref>
|-
| [[File:WheelArrangement 4-6-2.svg|80px]] || [[4-6-2]] || Pacific<ref name="railroad pocket-book" /><ref name="steam glossary" /><ref>{{cite encyclopedia| author=Marsden, Richard| url=http://www.lner.info/locos/A/a.shtml| title=LNER 4-6-2 Pacific Locomotives| encyclopedia=The London & North Eastern Railway (LNER) Encyclopedia| year=2008| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20080225085248/http://www.lner.info/locos/A/a.shtml| archive-date=25 February 2008}}</ref><ref>{{cite web| url=http://www.steamlocomotive.com/pacific/| title=Pacifics| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080125215157/http://www.steamlocomotive.com/pacific/| archive-date=25 January 2008}}</ref> || 6,800
|-
| [[File:WheelArrangement 4-6-4.svg|85px]] || [[4-6-4]] || Hudson,<ref>{{cite web| url=http://www.steamlocomotive.com/hudson/| title=Hudsons| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080127121700/http://www.steamlocomotive.com/hudson/| archive-date=27 January 2008}}</ref> Baltic<ref name="steam glossary">{{cite web| url=http://www.railway-technical.com/st-glos.shtml| title=Steam Locomotive Glossary| work=Railway Technical Web Pages| date=2007-06-28| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080128230325/http://www.railway-technical.com/st-glos.shtml| archive-date=28 January 2008}}</ref>
|-
| || [[4-6-6]] || Use on the [[Boston and Albany Railroad]].<ref>{{cite web|access-date=2021-04-21|title=Boston & Albany 4-6-6 Locomotives in the USA|url=https://www.steamlocomotive.com/locobase.php?country=USA&wheel=4-6-6&railroad=nyc|website=steamlocomotive.com}}</ref>
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-8-0.svg|80px]] || [[0-8-0]] || Eight-coupled<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 0-8-2.svg|85px]] || [[0-8-2]] || Transfer
|-
| [[File:WheelArrangement 0-8-4.svg|90px]] || [[0-8-4T|0-8-4]] || 
|-
| [[File:WheelArrangement 2-8-0.svg|90px]] || [[2-8-0]] || Consolidation<ref name="railroad pocket-book" /><ref name="steam glossary" /><ref>White (1968), p. 65.</ref> || 35,000
|-
| [[File:WheelArrangement 2-8-2.svg|95px]] || [[2-8-2]] || Mikado,<ref name="railroad pocket-book" /><ref name="steam glossary"/> Mike, MacArthur<ref name="Kalmbach glossary M">{{cite web| url=http://trains.com/trn/glossary/default.aspx?list=4&fl=m| title=Glossary of Common Railroad Terms: M| publisher=Kalmbach Publishing| access-date=2008-02-08| archive-date=24 February 2008| archive-url=https://web.archive.org/web/20080224095610/http://www.trains.com/trn/glossary/default.aspx?list=4| url-status=dead}}</ref><ref>{{cite web| url=http://www.steamlocomotive.com/mikado/| title=The Mikado Type Locomotive| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20130612223127/http://www.steamlocomotive.com/mikado/| archive-date=12 June 2013}}</ref>
|-
| [[File:WheelArrangement 2-8-4.svg|100px]] || [[2-8-4]] || Berkshire, Kanawha<ref>{{cite book|author=Farrell, Jack W.|title=North American steam locomotives: The Berkshire and Texas types|year=1989|work=Pacific Fast Mail|location=Edmonds, WA|isbn=0-915713-15-2}}</ref><ref>{{cite web| url=http://www.steamlocomotive.com/berkshire/| title=Berkshires & Kanawhas| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080126125639/http://www.steamlocomotive.com/berkshire/| archive-date=26 January 2008}}</ref>
|-
| [[File:WheelArrangement 2-8-6.svg|105px]] || [[2-8-6]] || ''Used only on four [[Mason Bogie]] locomotives''
|-
| [[File:WheelArrangement 4-8-0.svg|100px]] || [[4-8-0]] || Twelve Wheeler,<ref name="railroad pocket-book" /><ref name="LCyclo">{{cite encyclopedia| title=Locomotives: Whyte's Notation| encyclopedia=Locomotive Cyclopedia of American Practice| url=https://books.google.com/books?id=oMY1AQAAMAAJ&pg=PA106| publisher=Simmons-Boardman Publishing Corporation| year=1922| pages=106–107}}</ref> Mastodon<ref name=":2" />
|-
| [[File:WheelArrangement 4-8-2.svg|105px]] || [[4-8-2]] || Mountain,<ref name="steam glossary" /><ref>{{cite web| url=http://www.steamlocomotive.com/mountain/| title=Mountains| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080130083158/http://www.steamlocomotive.com/mountain/| archive-date=30 January 2008}}</ref> Mohawk ([[New York Central Railroad|NYC]])<ref>{{cite journal| journal=Model Railroader| title=New York Central Dual-service Mohawk|date=January 1941| publisher=Kalmbach Publishing| author=Taylor, Frank }}</ref>
|-
| [[File:WheelArrangement 4-8-4.svg|120px]] || [[4-8-4]] || Northern, Niagara, Confederation, Dixie, Greenbrier, Pocono, Potomac, Heavy Mountain (Atchison, Topeka, and Santa Fe), Golden State (Southern Pacific),<ref name="Northerns">{{cite web| url=http://www.steamlocomotive.com/northern/| title=Northerns| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080212235247/http://www.steamlocomotive.com/northern/| archive-date=12 February 2008}}</ref> Western, Laurentian ([[Delaware & Hudson Railroad]]), General, Wyoming ([[Lehigh Valley Railroad|Lehigh Valley]]<ref>{{cite web |url=http://www.steamlocomotive.com/northern/lv.shtml |title= Lehigh Valley Wyomings |access-date=2010-05-25 |url-status=dead |archive-url=https://web.archive.org/web/20100813015406/http://www.steamlocomotive.com/northern/lv.shtml |archive-date=13 August 2010 }}</ref>), Governor, [[Central of Georgia "Big Apple"|Big Apple]], [[Southern Pacific class GS-4|GS Series "Daylight"]] (Southern Pacific)<ref name="Northerns"/>
|-
| [[File:WheelArrangement 4-8-6.svg|120px]] || [[4-8-6]] || ''Proposed by [[Lima Locomotive Works|Lima]], never built''
|-
| [[File:WheelArrangement 6-8-6.svg|125px]] || [[6-8-6]] || Turbine, only used on the PRR S2 Steam Turbine || 1
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-10-0.svg|100px]] || [[0-10-0]] || Ten-coupled,<ref name="railroad pocket-book" /><ref name="0-10-0 profile">{{cite journal| url=http://www.trains.com/ctr/default.aspx?c=a&id=106| title=Steam locomotive profile: 0-10-0| journal=Classic Trains| publisher=Kalmbach Publishing| date=2006-07-03| author=Carlson, Neil| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20070929095552/http://www.trains.com/ctr/default.aspx?c=a&id=106| archive-date=29 September 2007}}</ref> Ten-wheel switch<ref name=":2" />
|-
| [[File:WheelArrangement 0-10-2.svg|105px]] || [[0-10-2]] || Union<ref name="0-10-0 profile" />
|-
| [[File:WheelArrangement 2-10-0.svg|105px]] || [[2-10-0]] || Decapod,<ref name="railroad pocket-book" /><ref name="Kalmbach glossary D">{{cite web| url=http://trains.com/trn/glossary/default.aspx?list=4&fl=d| title=Glossary of Common Railroad Terms: D| publisher=Kalmbach Publishing| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20070101163059/http://www.trains.com/trn/glossary/default.aspx?list=4&fl=d| archive-date=1 January 2007}}</ref> [[Russian locomotive class Ye|Russian Decapod]]
|-
| [[File:WheelArrangement 2-10-2.svg|110px]] || [[2-10-2]] || Santa Fe<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 2-10-4.svg|115px]] || [[2-10-4]] || Texas, Colorado ([[CB&Q]]), Selkirk (Canada)<ref>{{cite web| url=http://www.steamlocomotive.com/texas/| title=The Texas Type Locomotive| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080225063558/http://www.steamlocomotive.com/texas/| archive-date=25 February 2008}}</ref>
|- 
||| [[2-10-6]] || ''Proposed by [[Indian Railways]], never built''<ref>{{cite book |last=Hughes |first=Hugh |author-link= |date=1979 |title=Steam Locomotives in India, Part 3 - Broad Gauge |url=https://archive.org/details/steamlocomotives0000hugh/mode/2up |location= |publisher=The Continental Railway Circle |page=23 |isbn=9780950346946 |url-access=registration}}</ref>
|-
| [[File:WheelArrangement 4-10-0.svg|110px]] || [[4-10-0]] || Mastodon<ref name="railroad pocket-book" /><ref name="LCyclo" />
|-
| [[File:WheelArrangement 4-10-2.svg|115px]] || [[4-10-2]] || Reid Tenwheeler,<ref name="Paxton-Bourne">{{Paxton-Bourne|pages=10-11, 31}}</ref><ref name="Holland 1">{{Holland-Vol 1|pages=92-95, 123-124, 134-135}}</ref> [[Southern Pacific Railroad|Southern Pacific]], Overland,<ref>{{cite journal| journal=Trains| title=Baldwin's barnstorming behemoth|date=April 1954| author=Westing, Frederick }}</ref> Super Mountain<ref name=":2" />
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-12-0.svg|115px]] || [[0-12-0]] || 12-coupled
|-
| ||0-12-2|| Used in Argentina 
|-
| [[File:WheelArrangement 2-12-0.svg|120px]] || [[2-12-0]] || Centipede<ref name="railroad pocket-book" />
|-
| [[File:WheelArrangement 2-12-2.svg|125px]] || [[2-12-2]] || Javanic<ref name=":2" />
|30
|-
| [[File:WheelArrangement 2-12-4.svg|130px]] || [[2-12-4]] || 
|20
|-
||| [[2-12-6]] || ''Proposed by [[Lima Locomotive Works|Lima]], never built''
|-
| [[File:WheelArrangement 4-12-2.svg|135px]] || [[4-12-2]] || [[Union Pacific]]<ref>{{MR steam cyclopedia}}</ref> || 
|-
| colspan="3" |
|-
| [[File:WheelArrangement 4-14-4.svg|150px]] || [[4-14-4]] || [[Soviet locomotive class AA20|AA20]],<ref>{{cite web| url=http://www.aqpl43.dsl.pipex.com/MUSEUM/LOCOLOCO/russ/russrefr.htm| title=Russian Reforms| date=2001-10-06| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20101018053044/http://www.aqpl43.dsl.pipex.com/MUSEUM/LOCOLOCO/russ/russrefr.htm| archive-date=18 October 2010}}</ref> Soviet<ref name=":2" />|| 1
|-
| colspan="4" |
|-
! colspan="4" | Divided drive and duplex locomotives
|-
| colspan="4" |
|-
||| [[0-2-2-0]] || Used on the [[Mount Washington Cog Railway]]
|-
| || [[2-2-2-0]] ||
|-
| || [[2-2-2-2]] ||
|-
| || [[2-2-4-0T|2-2-4-0]] ||
|| 1
|-
| || [[4-2-2-0]] || Double single<ref>{{cite book |url=https://books.google.com/books?id=DuTvDwAAQBAJ&pg=PA63 |title=L&SWR Drummond Passenger and Mixed Traffic Locomotive Classes |year=2020 |publisher=Pen and Sward Transport |language=en |page=63|isbn=978-1-5267-6984-8 }}</ref>
|-
| || [[2-4-6-2]] ||
|
|-
| || 4-4-4-2 || Planned for proposed [[ACE 3000]] locomotive.
|-
| [[File:WheelArrangement 4-4-4-4.svg|115px]] || [[4-4-4-4]] || ([[PRR T1]])<ref>{{cite journal| journal=Trains| title=Riding the Pennsy T1| author=Russ, David|date=July 1943| publisher=Kalmbach Publishing }}</ref>
|53
|-
| [[File:WheelArrangement 6-4-4-6.svg|130px]] || [[6-4-4-6]] || ([[PRR S1]])<ref>{{cite journal| journal=Trains| title=They called her the big engine| author=Morgan, David P.|date=May 1965| publisher=Kalmbach Publishing }}</ref> || 1
|-
| [[File:WheelArrangement 4-4-6-4.svg|130px]] || [[4-4-6-4]] || ([[PRR Q2]])<ref>{{cite journal| journal=Trains| title=Instead of a 4-10-4|author1=Herring, S. E.  |author2=Morgan, David P. |name-list-style=amp |date=June 1966| publisher=Kalmbach Publishing }}</ref> || 26
|-
| [[File:WheelArrangement 4-6-4-4.svg|130px]] || [[4-6-4-4]] || ([[PRR Q1]]) || 1
|-
| colspan="4" |
|-
! colspan="4" |  Articulated locomotives (simple and compound)
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-4-4-0.svg|80px]] || [[0-4-4-0]] || 
|-
| [[File:WheelArrangement 2-4-0.svg|45px]] [[File:WheelArrangement 0-4-0.svg|38px]] || [[2-4-4-0]] || 
|5
|-
| [[File:WheelArrangement 0-4-0.svg|38px]] [[File:WheelArrangement 0-4-2.svg|45px]] || [[0-4-4-2]] || 
|-
| [[File:WheelArrangement 2-4-4-2.svg|100px]] || [[2-4-4-2]] ||Little River
|-
| <!-- [[File:WheelArrangement 4-4-6-2.svg|100px]] --> || [[4-4-6-2]] || Used by the Santa Fe<ref>"The Jointed-Boiler Locomotives," ''[[Trains (magazine)|Trains]]'' magazine, February 1945</ref> || 2
|-
| [[File:WheelArrangement 0-6-6-0.svg|115px]] || [[0-6-6-0]] || 
|-
| [[File:WheelArrangement 2-6-6-0.svg|120px]] || [[2-6-6-0]] || 
|-
| [[File:WheelArrangement 2-6-6-2.svg|125px]] || [[2-6-6-2]] || 
|1,300
|-
| [[File:WheelArrangement 2-6-6-4.svg|135px]] || [[2-6-6-4]] ||  || 60
|-
| [[File:WheelArrangement 2-6-6-6.svg|140px]] || [[2-6-6-6]] || Allegheny,<ref>{{cite web| url=http://www.steamlocomotive.com/allegheny/| title=The Allegheny Type Locomotive| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080127121645/http://www.steamlocomotive.com/allegheny/| archive-date=27 January 2008}}</ref> Blue Ridge || 68
|-
| [[File:WheelArrangement 4-6-6-2.svg|135px]] || [[4-6-6-2]] || ([[Southern Pacific class AM-2]])<ref name="SP compendium">{{cite book |author1=Diebert, Timothy S. |title=Southern Pacific Company Steam Locomotive Conpendium |author2=Strapac, Joseph A. |publisher=Shade Tree Books |year=1987 |isbn=0-930742-12-5 |name-list-style=amp}}</ref>
|-
| [[File:WheelArrangement 4-6-6-4.svg|140px]] || [[4-6-6-4]] || Challenger<ref>{{cite web| url=http://www.steamlocomotive.com/challenger/| title=The Challenger Type Locomotive| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20051201200632/http://www.steamlocomotive.com/challenger/| archive-date=1 December 2005}}</ref> || 252
|-
| colspan="4" |
|-
| || [[0-8-6-0T|0-8-6-0]]
|-
| colspan="4" |
|-
| [[File:WheelArrangement 2-6-8-0.svg|135px]] || [[2-6-8-0]] || (Southern Railway, Great Northern Railway)<ref name="2-8-8-2 profile">{{cite journal| journal=Classic Trains| title=Steam locomotive profile: 2-8-8-2| author=Carlson, Neil| date=2006-06-15| publisher=Kalmbach Publishing| url=http://trains.com/ctr/default.aspx?c=a&id=151| access-date=2008-02-08| url-status=live| archive-url=https://web.archive.org/web/20081116233532/http://www.trains.com/ctr/default.aspx?c=a&id=151| archive-date=16 November 2008}}</ref>
|39
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-8-8-0.svg|145px]] || [[0-8-8-0]] || Angus<ref>{{cite web | url=http://www.steamlocomotive.com/misc/wheels.shtml | title=American Steam Locomotive Wheel Arrangements | work=SteamLocomotive.com | date=1991-05-30 | access-date=2008-02-08 | last=Boylan | first=Richard | last2=Barris | first2=Wes | archive-url=https://web.archive.org/web/20080126123957/http://www.steamlocomotive.com/misc/wheels.shtml | archive-date=26 January 2008}}</ref>
|-
| [[File:WheelArrangement 2-8-8-0.svg|150px]] || [[2-8-8-0]] || Bull Moose
|-
| [[File:WheelArrangement 2-8-8-2.svg|160px]] || [[2-8-8-2]] ||Chesapeake 
|222
|-
| [[File:WheelArrangement 2-8-8-4.svg|165px]] || [[2-8-8-4]] || Yellowstone<ref>{{cite web| url=http://www.steamlocomotive.com/yellowstone/| title=The Yellowstone Type Locomotive| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20030203053537/http://www.steamlocomotive.com/yellowstone/| archive-date=3 February 2003}}</ref> || 78
|-
| [[File:WheelArrangement 4-8-8-2.svg|165px]] || [[4-8-8-2]] ||Cab Forward  || 195
|-
| [[File:WheelArrangement 4-8-8-4.svg|170px]] || [[4-8-8-4]] || [[Union Pacific Big Boy|Big Boy]]<ref>{{cite web| url=http://www.steamlocomotive.com/bigboy/| title=Union Pacific Big Boys| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20090922043838/http://www.steamlocomotive.com/bigboy/| archive-date=22 September 2009}}</ref> || 25<ref>{{cite web|title=Union Pacific Big Boy: The rebirth of a legend|url=http://trn.trains.com/news/news-wire/2013/08/union-pacific-big-boys|website=Trains|access-date=8 November 2016|date=23 August 2013|url-status=live|archive-url=https://web.archive.org/web/20150712003634/http://trn.trains.com/news/news-wire/2013/08/union-pacific-big-boys|archive-date=12 July 2015}}</ref>
|-
| colspan="4" |
|-
| [[File:WheelArrangement 2-10-10-2.svg|185px]] || [[2-10-10-2]] || (Santa Fe and Virginian railroads)<ref name="2-8-8-2 profile" /> || 20
|-
| colspan="4" |
|-
| [[File:WheelArrangement 2-8-8-8-2.svg|220px]] || [[2-8-8-8-2]] || [[Triplex locomotive|Triplex]] (Erie RR) || 3
|-
| [[File:WheelArrangement 2-8-8-8-4.svg|225px]] || [[2-8-8-8-4]] || Triplex (Virginian RR)<ref>{{cite web| url=http://www.steamlocomotive.com/articulated/virginianxa.shtml| title=Virginian Class XA Locomotives| work=SteamLocomotive.com| access-date=2008-02-08| url-status=dead| archive-url=https://web.archive.org/web/20080112002641/http://steamlocomotive.com/articulated/virginianxa.shtml| archive-date=12 January 2008}}</ref> || 1
|-
| colspan="4" |
|-
! colspan="4" | Garratt articulated locomotives
|-
| colspan="4" |
|-
| [[File:WheelArrangement 0-4-0+0-4-0.svg|75px]] || [[0-4-0+0-4-0]] || 
|-
| [[File:WheelArrangement 0-6-6-0.svg|x18px]] || [[0-6-0+0-6-0]] || 
|-
| [[File:WheelArrangement 2-4-4-2.svg|x18px]] || [[2-4-0+0-4-2]] || 
|-
| [[File:WheelArrangement 2-4-2+2-4-2.svg|x18px]] || [[2-4-2+2-4-2]] || 
|-
| [[File:WheelArrangement 2-6-6-2.svg|x18px]] || [[2-6-0+0-6-2]] || 
|-
| [[File:WheelArrangement 2-6-2+2-6-2.svg|x18px]] || [[2-6-2+2-6-2]] || Double Prairie
|-
| [[File:WheelArrangement 2-8-8-2.svg|x18px]] || [[2-8-0+0-8-2]] || 
|-
| [[File:WheelArrangement 2-8-2+2-8-2.svg|x17px]] || [[2-8-2+2-8-2]] || Double Mikado
|-
| [[File:WheelArrangement 4-4-2+2-4-4.svg|x18px]] || [[4-4-2+2-4-4]] || 
|-
| [[File:WheelArrangement 4-6-6-4.svg|x18px]] || [[4-6-0+0-6-4]] || 
|-
| [[File:WheelArrangement 4-6-2+2-6-4.svg|x17px]] || [[4-6-2+2-6-4]] || Double Pacific
|-
| [[File:WheelArrangement 4-6-4+4-6-4.svg|x18px]] || [[4-6-4+4-6-4]] || Double Hudson 
|-
| [[File:WheelArrangement 4-8-8-4.svg|x18px]] || [[4-8-0+0-8-4]] || 
|-
| [[File:WheelArrangement 4-8-2+2-8-4.svg|x18px]] || [[4-8-2+2-8-4]] || 
|-
| [[File:WheelArrangement 4-8-4+4-8-4.svg|x18px]] || [[4-8-4+4-8-4]] || 
|}

== See also ==
* [[AAR wheel arrangement]]
* [[Swiss locomotive and railcar classification]]
* [[UIC classification]]
* [[Wheel arrangement]]

== References ==
{{Reflist}}

== Further reading ==
* {{cite web| url=http://www.steamlocomotive.com/misc/wheels.shtml| title=American Steam Locomotive Wheel Arrangements| website=SteamLocomotive.com| access-date=2008-02-08| last1=Boylan| first1=Richard| last2=Barris| first2=Wes| date=1991-05-30| archive-date=26 January 2008| archive-url=https://web.archive.org/web/20080126123957/http://www.steamlocomotive.com/misc/wheels.shtml| url-status=dead}}

== External links ==
* {{Commons category-inline|Whyte notation}}

{{Whyte types}}
{{Locostyles}}

In the various names above of a 4-8-4, omitted was the letters "F E F" which simply means: four eight four.

[[Category:Whyte notation| ]]
[[Category:1900s introductions]]
[[Category:Locomotive classification systems]]
[[Category:Locomotives by wheel arrangement| ]]
[[Category:Notation]]