Editing NIR 1 Class (section)

==Early service life==
The '''DH class''' of [[Northern Ireland Railways]] consisted of three diesel-hydraulic shunting [[locomotive]]s numbered 1, 2 & 3. They were built by the [[English Electric]] Company at their [[Vulcan Foundry]] works in [[Newton-le-Willows]] in 1969. The works numbers 3954–3956 in the EE list, and D1266–D1268 in the VF list. They were of [[0-6-0]] [[Whyte notation|wheel arrangement]] and fitted with [[W.H. Dorman & Co|Dorman]] 12QTV engines of {{convert|620|hp|kW|-1|abbr=on}}, connected to an EE [[Twin Disc]] [[torque converter]] and a Wiseman [[final drive]]. They weighed {{convert|42.5|t|2}} and had a maximum speed of {{convert|29|mph|km/h|0|abbr=on}}. They are often referred to with their, "DH," prefix.

The locomotives were of EE's standard 'Stephenson' class, and were obtained primarily for shunting work, trip freights and engineer's trains. Locomotive No. 1 was the first to enter service on 31 July 1969, with No. 2 following on 27 September and No. 3 on 4 October.<ref name="ITG1">{{cite web |url=http://www.irishtractiongroup.com/ITG_locos/loco_NIR1.htm |title=1 |accessdate=2024-09-30 |work=[[Irish Traction Group]] |archiveurl=https://web.archive.org/web/20080512233429/http://www.irishtractiongroup.com/ITG_locos/loco_NIR1.htm |archivedate=2008-05-12}}</ref> However, the locomotives were not particularly successful due to problems with the engines overheating regularly while in service.