The locomotive was No.4, in the locomotive fleet at the Royal Navy Cordite Factory [RNCF] at Holton Heath.
The RNCF, was set up at Holton Heath, Dorset in World War 1 to manufacture cordite for the Royal Navy.
It was reactivated in World War 2 to manufacture gun propellants for the Admiralty and its output was supplemented by the Royal Navy Propellant Factory at Caerwent, Monmouthshire.
After the end of the World War 2, the explosive manufacturing areas of the site were closed down, and some areas of the site reopened as an Admiralty Research Establishment.
The Admiralty Research Establishment became part of the Defence Agency.
Holton Heath finally closed in the late 1990s