The Info List - Wheel Arrangement

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In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive.[1] Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country. Within a given country, different notations may also be employed for different kinds of locomotives, such as steam, electric, and diesel powered. Especially in steam days, wheel arrangement was an important attribute of a locomotive because there were many different types of layout adopted, each wheel being optimised for a different use (often with only some being actually "driven"). Modern diesel and electric locomotives are much more uniform, usually with all axles driven.


1 Major notation schemes 2 Comparison of wheel arrangements and wheel picture 3 See also 4 References

Major notation schemes[edit]

Wikimedia Commons has media related to Wheel arrangements.

The main notations are the Whyte notation
Whyte notation
(based on counting the wheels), the AAR wheel arrangement notation (based on counting either the axles or the bogies), and the UIC classification of locomotive axle arrangements (based on counting either the axles or the bogies). Whyte notation
Whyte notation
is generally used for steam locomotives throughout the United States, Canada, the United Kingdom
United Kingdom
and Ireland. For diesels and electrics, North America
North America
uses the AAR wheel arrangement scheme while British practice uses a slightly simplified form of the European UIC classification scheme (except for small diesel shunters, where Whyte notation is used). In mainland Europe, the UIC classification scheme is generally used for all locomotive types including steam, with some exceptions. In France, the UIC classification is used for diesels and electrics while a scheme similar to the Whyte notation, but counting axles insteads of wheels, is used for steam locomotives. Notably, Switzerland
had its own separate notation system until 1989, with the Swiss locomotive and railcar classification now only retained for its narrow gauge railways.

AAR wheel arrangement - Used largely throughout the US and Canada
for diesel and electric locomotives. UIC classification - Used in mainland Europe
for all locomotive types. Used in the UK for electric and large diesel locomotives. Whyte notation
Whyte notation
- Used in North America, the UK and Ireland
for steam locomotives, and for shunters (US: switchers) in the UK.

Comparison of wheel arrangements and wheel picture[edit]

VDEV/VMEV/UIC-System Whyte-Notation American name picture scheme locomotive front is to the left

A1 0-2-2


A2 0-2-4


1A 2-2-0 Planet oO

1A1 2-2-2 Patentee oOo

1A2 2-2-4


2′A 4-2-0 Crampton, Norris, Jervis ooO

2′A1 4-2-2 Single Driver ooOo

2A2 4-2-4


3A 6-2-0 Crampton oooO

N/A 0-3-0


B 0-4-0 Four-Wheel-Switcher OO

B1 0-4-2


B2′ 0-4-4 Forney OOoo

B3′ 0-4-6


1B 2-4-0 Hanscom oOO

1′B1′ 2-4-2 Columbia oOOo

1B2′ 2-4-4


1B3′ 2-4-6


2′B 4-4-0 American, Eight-Wheeler ooOO

2′B1′ 4-4-2 Atlantic ooOOo

2′B2′ 4-4-4 Jubilee ooOOoo

2′B3′ 4-4-6


C 0-6-0 Six-Wheel-Switcher OOO

C1 0-6-2


C2′ 0-6-4


1′C 2-6-0 Mogul oOOO

1′C1′ 2-6-2 Prairie oOOOo

1′C2′ 2-6-4 Adriatic oOOOoo

1′C3′ 2-6-6


2′C 4-6-0 Ten-Wheeler ooOOO

2′C1′ 4-6-2 Pacific ooOOOo

2′C2′ 4-6-4 Hudson, Baltic ooOOOoo

D 0-8-0 Eight-Wheel-Switcher OOOO

D1 0-8-2


D2′ 0-8-4


D3′ 0-8-6


1′D 2-8-0 Consolidation oOOOO

1′D1′ 2-8-2 Mikado oOOOOo

1′D1′ 2-8-2T MacArthur oOOOOo

(1′D1′)(1′D1′) 2-8-2+2-8-2 Double Mikado, Garrett oOOOOo+oOOOOo

1′D2′ 2-8-4 Berkshire oOOOOoo

1′D3′ 2-8-6


2′D 4-8-0 Twelve-Wheeler, Mastodon ooOOOO

2′D1′ 4-8-2 Mountain, Mohawk (NYC) ooOOOOo

2′D2′ 4-8-4 Northern, General Service (SP), Golden State (SP), Niagara (NYC), Wyoming ooOOOOoo

2D3 4-8-6


3′D3′ 6-8-6 nameless (Pennsylvania Railroad Steam Turbine) oooOOOOooo

E 0-10-0 Ten-Wheel Switcher OOOOO

E1′ 0-10-2 Union OOOOOo

1′E 2-10-0 Decapod oOOOOO

2′E 4-10-0 Mastodon ooOOOOO

1′E1′ 2-10-2 Santa Fe oOOOOOo

1′E2′ 2-10-4 Texas oOOOOOoo

2′E1′ 4-10-2 Southern Pacific, Overland ooOOOOOo

F 0-12-0 Pennsylvania, Twelve-Wheel-Switcher OOOOOO

1′F 2-12-0 Centipede oOOOOOO

1′F1′ 2-12-2 Javanic oOOOOOOo

2′F1′ 4-12-2 Union Pacific ooOOOOOOo

2′G2′ 4-14-4


nameless (AA) 0-2-2-0


B′B 0-4-4-0 nameless (Mallet) OO OO

B′B1 0-4-4-2 nameless (Mallet) OO OOo

2′BB2′ 4-4-4-4 nameless (Pennsylvania Railroad Duplex) ooOO OOoo

3′BB3′ 6-4-4-6

oooOO OOooo

2′CB2′ 4-6-4-4 nameless (Pennsylvania Railroad Duplex) ooOOO OOoo

C′C 0-6-6-0 Erie (Mallet) OOO OOO

(1′C)C 2-6-6-0 nameless (Mallet) oOOO OOO

(1′C)C1′ 2-6-6-2 Mallet Mogul (SP), Prairie Mallet (ATSF) oOOO OOOo

(1′C)C2′ 2-6-6-4 nameless (Simple articulated) oOOO OOOoo

(2′C)C2′ 4-6-6-4 Challenger (Simple articulated) ooOOO OOOoo

(1′C)C3′ 2-6-6-6 Allegheny (Mallet/Simple articulated) oOOO OOOooo

D′D 0-8-8-0 Angus (Mallet) OOOO OOOO

(1′D)D 2-8-8-0 Bullmoose (Mallet) oOOOO OOOO

(1′D)D1′ 2-8-8-2 Chesapeake, Mallet consolidation (Mallet) oOOOO OOOOo

(1′D)D2′ 2-8-8-4 Yellowstone (Mallet/Simple articulated) oOOOO OOOOoo

(2′D)D1′ 4-8-8-2 Cab Forward (Simple articulated) ooOOOO OOOOo

(2′D)D2′ 4-8-8-4 Big Boy (Simple articulated) ooOOOO OOOOoo

(1′E)E1′ 2-10-10-2 Virginian (Mallet) oOOOOO+OOOOOo

(2′C1′)(1′C2′) 4-6-2+2-6-4 Double Pacific (Garratt) ooOOOo+oOOOoo

(2′C2′)(2′C2′) 4-6-4+4-6-4 Double Hudson (Garratt) ooOOOoo+ooOOOoo

(2′D)(D2′) 4-8-0+0-8-4 Double Mastodon (Garratt) ooOOOO+OOOOoo

(2′D1′)(1′D2′) 4-8-2+2-8-4 Double Mountain (Garratt) ooOOOOo+oOOOOoo

(2′D2′)(2′D2′) 4-8-4+4-8-4 Double Northern (Garratt) ooOOOOoo+ooOOOOoo

See also[edit]

has the property: wheel arrangement (P2978) (see talk; uses)

Co-Co locomotives


^ "Wheel Arrangements". Railway Technical Web Pages. 1 August 2011. Retrieved 1 August 2011. 

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Cab positioning Short hood
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/ Long hood

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Wheel arrangement

AAR wheel arrangement UIC classification Swiss classificat