Whyte notation 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 twentieth cen ...

, a 2-2-4T is a

railroad Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prep ...

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, oil or, rarely, wood) to heat water in the loco ...

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 ...

s and four

trailing wheel On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle ( wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, ...

s. This was an unusual wheel arrangement, only used on a few specialised 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'', Cre ...

: 1A2 (also known as German classification and

Italian 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'', Cre ...

) *

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 In the Turkish classification system for railway locomotives, the number of powered axles are followed by the total number of axles. It is identical to the Swiss system except that the latter places a slash between the two numbers. Thus 0-6-0 beco ...

: 14 *

Swiss classification For more than a century, the Swiss locomotive, multiple unit, motor coach and railcar classification system, in either its original or updated forms, has been used to name and classify the rolling stock operated on the railways of Switzerland. ...

: 1/4

UK examples

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

tank locomotive A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank loc ...

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 NER may refer to: * New European Recordings, a record label * ISO 3166-1 three letter code for Niger * Named entity recognition, a text processing task that identifies certain words as belonging to one class or another * Northeast Regional, an Amtr ...

, later

class X3 Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...

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 arrangemen ...

tender locomotive A tender or coal-car (US only) is a special rail vehicle hauled by a steam locomotive containing its fuel (wood, coal, oil or torrefied biomass) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, s ...

s. All four were inherited by the

London and North Eastern Railway The London and North Eastern Railway (LNER) was the second largest (after LMS) of the " Big Four" railway companies created by the Railways Act 1921 in Britain. It operated from 1 January 1923 until nationalisation on 1 January 1948. At th ...

(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 is a museum in York 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 historically significant ...

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

References

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