User:Dark Lord Of Time/Whyte notation

A selection of early 20th century locomotive types according to their Whyte notation and their comparative size

Whyte notation as of 1906. From a handbook for railroad industry workers published in 1906.

The Whyte notation for labeling steam locomotives by wheel arrangement was made by Frederick Methvan Whyte and came into use in the early 20th century. Whyte's system counts the number of leading wheels, then the number of driving wheels, and finally the number of trailing wheels, groups of numbers being separated by dashes.

Thus, a locomotive with two leading axles (and thus four wheels) in front, then three driving axles (six wheels) and followed by one trailing axle (two wheels) is classified as a 4-6-2.

Limitations

The limitations of the Whyte system in labeling engines that did not fit the standard steam locomotive pattern led to the design of other forms of classification. Most generally used in Europe is the UIC classification scheme, based on German practice, which can more completely define the exact layout of a locomotive.

Naming

In American (and sometimes a British) practice, most wheel arrangements in common use were given names, often from the name of the first such engine built. (For example, the 2-2-0 is named Planet.) (This naming convention is similar to the naming of warship classes.)

Common wheel arrangements

Here is a list of the most common wheel arrangements: in the picture the front of the locomotive is to the left.

Arrangement (locomotive front is to the left)	Whyte classification	Name
Non-articulated locomotives
	0-2-2	Northumbrian
	2-2-0	Planet
	2-2-2	Single, Jenny Lind
	2-2-4
	4-2-0	Jervis
	4-2-2	Bicycle
	4-2-4]]
	6-2-0	Crampton
	0-4-0	Four-Coupled
	0-4-2
	0-4-4	Forney
	2-4-0	Porter, 'Old English'
	2-4-2	Columbia
	2-4-4
	4-4-0	American, Eight-wheeler
	4-4-2	Atlantic
	4-4-4	Reading, Jubilee (Canada)
	0-3-0	(one driving wheel per axle; used on Patiala State monorail and also on the Listowel and Ballybunion Railway)
	0-6-0	Six-Coupled, Bourbonnais (France), USRA 0-6-0 (United States)
	0-6-2
	0-6-4	Forney six-coupled
	2-6-0	Mogul
	2-6-2	Prairie
	2-6-4	Adriatic
	2-6-6
	4-6-0	Ten-Wheeler (not Britain)
	4-6-2	Pacific
	4-6-4	Hudson, Baltic
	0-8-0	Eight-Coupled, USRA 0-8-0 (United States)
	0-8-2
	0-8-4
	2-8-0	Consolidation
	2-8-2	Mikado, Mike, MacArthur
	2-8-4	Berkshire, Kanawha
	2-8-6	Used only on four Mason Bogie locomotives
	4-8-0	Mastodon, Twelve-Wheeler
	4-8-2	Mountain, Mohawk
	4-8-4	Northern, Niagara, Confederation, Dixie, Greenbrier, Pocono, Potomac, Golden State, Western, General, Governor, Big Apple, GS Series "Daylight" (Southern Pacific)
	4-8-6	Proposed by Lima, never built
	6-8-6	(PRR S2 steam turbine locomotive)
	0-10-0	Ten-Coupled, (rarely) Decapod
	0-10-2	Union
	2-10-0	Decapod, Russian Decapod
	2-10-2	Santa Fe, Central, Decapod (only on the Southern Pacific)
	2-10-4	Texas, Colorado (CB&Q), Selkirk (Canada)
	4-10-0	Mastodon, Gobernador (in honor of El Gobernador)
	4-10-2	Southern Pacific, Overland
	0-12-0	Twelve-Coupled
	2-12-0	Centipede
	2-12-2	Javanic
	2-12-4
	4-12-2	Union Pacific
	4-14-4	AA20
Duplex locomotives
	4-4-4-4	(PRR T1)
	6-4-4-6	(PRR S1)
	4-4-6-4	(PRR Q2)
	4-6-4-4	(PRR Q1)
Mallet (simple and compound) articulated locomotives
	0-4-4-0	Bavarian BB II
	2-4-4-0
	0-4-4-2
	2-4-4-2
	0-6-6-0	Erie
	2-6-6-0	Denver & Salt Lake
	2-6-6-2
	2-6-6-4	Norfolk & Western
	2-6-6-6	Allegheny, Blue Ridge
	4-6-6-2	(Southern Pacific class MM-2)
	4-6-6-4	Challenger
	2-6-8-0	(Southern Railway, Great Northern Railway)
	0-8-8-0	Angus
	2-8-8-0	Bull Moose
	2-8-8-2	Chesapeake
	2-8-8-4	Yellowstone
	4-8-8-2	Southern Pacific cab forward classes AC-4 through AC-12 (except AC-9)
	4-8-8-4	Big Boy
	2-10-10-2	(Santa Fe and Virginian railroads)
	2-8-8-8-2	Triplex (Erie RR)
	2-8-8-8-4	Triplex (Virginian RR)
Garratt articulated locomotives
	0-4-0+0-4-0
	2-6-2+2-6-2

References

• Boylan, Richard, and Barris, Wes (1991-05-30). "American Steam Locomotive Wheel Arrangements". SteamLocomotive.com. Retrieved 2008-02-08.{{cite web}}: CS1 maint: multiple names: authors list (link)
• White, John H., Jr. (1968). A History of the American Locomotive - Its Development: 1830-1880. New York: Dover Publications. ISBN 0-486-23818-0.{{cite book}}: CS1 maint: multiple names: authors list (link)