This locomotive was built in 1953 for the Ministry of Defence by the Hunslet Engine Company to the design used to supply to the Ministry of Defence and is thus regarded as an Austerity type locomotive.
See LNER class J94 for details.
Despite being built in 1953 the locomotive did not enter service until when it worked at the General Stores Sub-Depot at Steventon as WD198. It then moved to Central Ordnance Depot, Bicester in 1958 and finally to HQ Engineer Resources at Long Marston in 1961.
Following a long period in store it was restored to working order and given the name Royal Engineer in 1971. A further overhaul followed in 1987/88 and, when withdrawn from service in 1991, it was the last operational steam locomotive owned by the Army.
The locomotive was part of a collection of railway items acquired by the Royal Corps of Transport Museum Trust for eventual display at a new museum under development at Chatham. As an interim measure it was placed on loan to the Isle of Wight Steam Railway and, following the fitting of Westinghouse air brake equipment, was put to work on passenger services.
In 2001 direct responsibility for the care of the locomotive passed to the National Army Museum who confirmed the loan agreement.
In 2005 Royal Engineer was joined on the Island by sister Army Austerity locomotive No.WD192 Waggoner. In May 2008 the National Army Museum transferred the ownership of both Army locomotives to the Isle of Wight Steam Railway.
The locomotive is currently undergoing repairs on the Isle of Wight Steam Railway.