{{Short description|Tank locomotive wheel arrangement}} {{Refimprove|date=December 2009}}
[[File:WheelArrangement 2-4-4.svg|thumb|right|200px|Diagramatic representation of 2-4-4. Front of engine to the left.]] [[Image:BRBL 6 Bldr.jpg|thumb|250px|2-4-4 [[Mason Bogie locomotive]] #6 on the [[Boston, Revere Beach and Lynn Railroad]] as built in 1886.]] [[File:Tk locomotive.jpg|thumb|250px|[[OKf100|Lithuanian Tk]]]] Under the [[Whyte notation]] for the classification of steam locomotives by wheel arrangement, 2-4-4 is a [[steam locomotive]] with two unpowered [[leading wheel]]s followed by four powered [[driving wheel]]s and four unpowered [[trailing wheel]]s. This configuration was only used for [[tank locomotive]]s. ==Equivalent classifications== Other equivalent classifications are: *[[UIC classification]]: '''1B2''' (also known as German classification and [[Italian classification]]) *[[French classification]]: '''122''' *[[Turkish classification]]: '''25''' *[[Swiss classification]]: '''2/5'''
The equivalent [[UIC classification]] is '''1′B2′ t''' (or '''(1′B)2′ t ''' for a Mason Bogie).
==Examples== This unusual wheel arrangement does not appear to have been used on the [[Main line (railway)|mainline]] railways in the UK. It was however one of the configurations used on the [[Mason Bogie locomotive|Mason Bogie]] [[articulated locomotive]]s, in the USA during the 1870s and 1880s. Five examples were constructed at the [[Mason Machine Works]] for the [[narrow gauge]] [[Boston, Revere Beach and Lynn Railroad]] 1883–1887. The railway subsequently received twenty-one further examples between 1900 and 1914, constructed by the [[Taunton Locomotive Manufacturing Company]], [[Manchester Locomotive Works]], and [[ALCO]]. Developmentally, there are two logical ways of reaching this wheel formula: to add a forward axle to a Forney locomotive to improve its ability to negotiate curves, or to add a second trailing axle to a Columbia design, notably in a 2-4-4(T) configuration to expand its coal capacity.
Four 2-4-4T passenger locomotives were built by the Czechoslovak Škoda for Lithuania in 1932 and marked as Tk class. They were seized by the USSR in 1940, then by the Germans.<ref>Vitaliy A. Rakov, ''Lokomotivy otechestvennyh zheleznyh dorog 1845-1955'', Moscow 1995, {{ISBN|5-277-00821-7}} (n Russian), p.333</ref> One was used after World War II in Poland as [[OKf100|OKf100-1]] until 1950.<ref>Paweł Terczyński, ''Atlas parowozów'', Poznań, 2003, {{ISBN|83-901902-8-1}}, p. 94</ref>
Other tank locomotives with 2-4-4T arrangement: *[[Bavarian D XII]] *French T5 6601 - 6637 of AL railway
==References== {{Reflist}} {{Whyte types}}
[[Category:2-4-4T locomotives| ]] [[Category:Tank locomotives|4,2-4-4T]] [[Category:Whyte notation|4,2-4-4]]