There is some discrepancy about the position of the steam engine. It was provided by Robey & Co., Lincoln and was used when low river levels prevented sufficient water being drawn off to power the turbine for the eight-mill range. The Nobel Plan shows it situated between the main tramway and the loop siding serving the mills. However, Moses indicates it as immediately east of the watch house and this appears to be corroborated by photographs, which show a building, taller than the adjacent Watch House and with a ventilator in the roof. On the ground there is a large, brick-lined pit at this spot which could be an engine pit. An underground flue ran from the Engine House, up the hillside to the north to a chimney (SN91380826). Although the building said by Moses to have housed the engine is not shown on the OS 1/2500 (1877) the chimney is. It is therefore possible that the engine was originally housed elsewhere.

References:
Nobel Industries Ltd. (1927) Block Plan of Glyn Neath Black Powder Factory. NMRW
Moses, T.L. Annotated copy of OS 1/2500 (1918). NMRW

D.J.Percival, 18 October 2006