Hi Astwood,
It has just occurred to me, that as your relative was an engineer, and maybe his job was to monitor and maintain the blast engine.
Would the structure for this also include accommodation. Not actually in the engine, but accommodation attached to it. Effectively the same building.
I know that several engineers in London actually lived on the premises of sewage pumping stations, living next door to steam driven beam engines, and this accommodation being purpose built.
Your relative would have also possibly been in charge of a crew of workmen.
Steve.