The Northern Ireland Railways DH class was a class of three diesel-hydraulic shunting locomotives obtained in 1969. All three have now been withdrawn, and two have since been rebuilt for work in Sri Lanka.
Early service life
The DH class of Northern Ireland Railways consisted of three diesel-hydraulic shunting locomotives 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 wheel arrangement and fitted with Dorman 12QTV engines of , connected to an EE Twin Disc torque converter and a Wiseman final drive. They weighed and had a maximum speed of . 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. However, the locomotives were not particularly successful due to problems with the engines overheating regularly while in service.
Withdrawal from service and initial preservation
All three were put into store during the late 1980s, the first in 1986 and the last two in May 1989. The Irish Traction group had approached NIR in August 1989 hoping to run a farewell excursion with No. 2 in September 1989, but this plan failed after No. 2 suffered a catastrophic engine failure on Saturday 9 September 1989 (the day before the excursion),