Whyte notation 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, and came into use in the early twenti ...

, a 2-2-4T is a

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

that has two

leading wheel The leading wheel or leading axle or pilot wheel of a steam locomotive is an unpowered wheel or axle located in front of the driving wheels. The axle or axles of the leading wheels are normally located on a leading truck. Leading wheels are used ...

s followed by two coupled

driving wheel On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled t ...

s and four

trailing wheel On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (Wheelset (rail transport), wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing Bogie, t ...

s. This was an unusual wheel arrangement, only used on a few specialised locomotives. This wheel arrangement is only used for tank locomotives.

Equivalent classifications

Other equivalent classifications are: *

UIC classification The UIC classification of locomotive axle arrangements, sometimes known as the German classification''The Railway Data File''. Leicester: Silverdale, 2000. p. 52. . or German system,Kalla-Bishop P.M. & Greggio, Luciano, ''Steam Locomotives'', Cr ...

: 1A2 (also known as German classification and Italian classification) *

French classification Under the French classification system for locomotive wheel arrangements, the system is slightly different for steam and electric/diesel vehicles. Steam The French system counts axles, rather than wheels. As with Whyte notation, a conventional r ...

: 112 * Turkish classification: 14 * Swiss classification: 1/4

UK examples

In the United Kingdom, the North Eastern Railway, had four

tank locomotive A tank locomotive is a steam locomotive which carries its water in one or more on-board water tanks, instead of a more traditional tender (rail), tender. Most tank engines also have Fuel bunker, bunkers (or fuel tanks) to hold fuel; in a #Tender ...

s of this wheel arrangement, all of which had previously been rebuilt from other types. They were: No. 66 ''Aerolite'' rebuilt as a 2-2-4T in 1902 and later known as in LNER class X1; No. 957, which had been rebuilt from a BTP class 0-4-4T in 1903 and later classified as X2 class. NER 190 Class, later class X3 had two members, Nos. 190 and 1679, both rebuilt from

2-2-2 Under the Whyte notation for the classification of steam locomotives, 2-2-2 represents the wheel arrangement of two leading wheels on one axle, two powered driving wheels on one axle, and two trailing wheels on one axle. The wheel arrangement both ...

tender locomotive A tender is a special railroad car, rail vehicle hauled by a steam locomotive containing its fuel (wood fuel, wood, coal, fuel oil, oil or torrefaction, torrefied biomass) and water. Steam locomotives consume large quantities of water compared ...

s. All four were inherited by the

London and North Eastern Railway The London and North Eastern Railway (LNER) was the second largest (after London, Midland and Scottish Railway, LMS) of the "Big Four (British railway companies), Big Four" railway companies created by the Railways Act 1921 in Britain. It ope ...

(LNER) at the time of its formation on 1 January 1923, and withdrawn from service between 1931 and 1937. No. 66 ''Aerolite'' has been preserved at the

National Railway Museum The National Railway Museum (NRM) is a museum in York, England, forming part of the Science Museum Group. The museum tells the story of rail transport in Britain and its impact on society. It is the home of the national collection of historical ...

York York is a cathedral city in North Yorkshire, England, with Roman Britain, Roman origins, sited at the confluence of the rivers River Ouse, Yorkshire, Ouse and River Foss, Foss. It has many historic buildings and other structures, such as a Yor ...

References

{{Whyte types 2,2-2-4 2,2-2-4T