NZR X class

When the first X was completed in 1908 at NZR's Addington Workshops in Christchurch, it was the very first 4-8-2 tender locomotive built in the world. The 4-8-2 design went on to be popular in the United States and was nicknamed the "Mountain" type; one theory suggests this name stems from the mountainous terrain that inspired the X's design,{{sfn|Palmer|Stewart|1965|p=86}} while another suggests the Chesapeake and Ohio Railway first coined the name in reference to its 4-8-2s of 1911 that were built to operate in the Allegheny Mountains.

The X class were restricted to the {{convert|93|mi|km}} Taumarunui to Taihape section for some years, as the track north and south was 53 lb/yd (26.3 kg/m) rather than 70 lb/yd (34.8 kg/m); and their trains were restricted to {{convert|25|mph|km/h|abbr=on}} for passenger trains or {{convert|20|mph|km/h|abbr=on}} for goods trains; a source of frustration to general manager Hiley who would have liked to run them over the entire NIMT (they had had to be partially dismantled for their initial journey to Taihape).{{sfn|Pierre|1981|pp=203–205}}

The X class initially operated as the freight counterpart of the passenger A class, but they struggled to operate at speeds higher than {{convert|50|km/h|mph|abbr=on}}.{{sfn|Palmer|Stewart|1965|p=86}} They were built as de Glehn compound locomotives, but during the 1940s, most of the class were converted to simple, superheated locomotives.{{sfn|Palmer|Stewart|1965|p=121}} This increased their power but did not prolong their lives and most were officially withdrawn from service on 2 March 1957,{{sfn|Palmer|Stewart|1965|p=121}} though a few had been taken out of service earlier and two were sold to the Ohai Railway Board (ORB) in 1946 that operated a private industrial line at the end of the Wairio Branch.

When the ORB introduced diesel locomotives in 1968, X 442 was donated to the New Zealand Railway and Locomotive Society, and it was eventually stored at Ferrymead in Christchurch.{{sfn|Cavalcade125|1988|p=7}} In 2002, X 442 was relocated to the Feilding and District Steam Rail Society depot in Feilding.{{cite web|url=http://steamrail.org.nz/vehicles/x442/x442info.html|title=X 442 Information|publisher=Feilding and District Steam Rail Society|access-date=23 March 2019}} Two X class boilers are held by Mainline Steam Trust.

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• {{Cite book | author1=Barry, Colin |author2=Brouwer, John | author3 =Dash, Colin |author4 =Dickenson, Peter|author5=Shalders, Bruce| title=Cavalcade 125 | publication-date=1988 | publisher=Ferrymead 125 Committee | url=https://trove.nla.gov.au/work/19528333 | access-date=22 March 2019 |ref={{sfnref|Cavalcade125|1988}}}}
• {{cite book|last1=Heath|first1=Eric|author-link1=Eric Heath (artist)|last2=Stott|first2=Bob|author-link2=Bob Stott|title=Classic Steam Locomotives of New Zealand|publisher=Grantham House|date=1993|ISBN=1869340361}}
• {{Palmer & Stewart}}
• {{cite book |last= Pierre |first= W.A. (Bill) |title= North Island Main Trunk: An Illustrated History |year= 1981 |publisher= A.H. & A.W. Reed |location= Auckland |isbn= 0-589-01316-5 }}

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• [http://www.trainweb.org/nzsteam/x_class.html New Zealand Railways Steam Locomotives - Class X]
• [https://nzetc.victoria.ac.nz/tm/scholarly/Gov03_05Rail-fig-Gov03_05Rail047a.html An X class locomotive] ex-Petone Workshops with a new superheated boiler c1928

{{NZR Locomotives}}

X class

Category:4-8-2 locomotives

Category:Compound locomotives

Category:3 ft 6 in gauge locomotives of New Zealand

Category:Railway locomotives introduced in 1908

Category:2′D1′ h4v locomotives

Category:2′D1′ h4 locomotives