"Gwen", while of the same design as the WW1 loco's, was built for John Knowles & Co and worked at their clay processing works near Woodville in Leicestershire. "Gwen" was the second loco of this design for this company - the first was "Jack" Hunslet 684/1898 - it survives operational at Leeds Industrial Museum. "Gwen" is Hunslet 1404/1920. The WW1 loco's were built for the Royal Army Service Corps Depot at Deptford (not far from Woolwich Arsenal) - 12 were built.
The best source of information is "An illustrated history of 18 inch gauge steam railways" by Mark Smithers and published by the Oxford Publishing Co in 1993 ISBN 0-86093-499-3.
Picture below, (my father had a habit of photographing dark objects against a dark background), Bicton Gardens 1963 with myself and my brother alongside "Woolwch" (Avonside 1748/1916). This is the last remaining steam loco from Woolwich Arsenal.
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