This locomotive was built by Hudswell Clarke in 1946 for the Ministry of Supply. On delivery it was sent to the West Chirton depot near Wallsend, Northumberland. After two years it was 'posted' to the WD Proof and Experimental Establishment, Eskmeals, Cumberland. In February 1957, it was deemed surplus to requirements and sold to the Millom and Askham Haematite and Iron Co Ltd.

After delivery to the ironworks, the engine was stored until 1963, then given a full overhaul and set to work at the Hodbarrow ironstone mine. When Hodbarrow closed, the loco returned to Millom and at about this time it gained a set of buffers from a Sentinel loco. In 1968 Millom Haematite ceased operation so Hudswell Clarke 1742 became surplus to requirements. Sold by the receivers, the engine was purchased by a QRS member, arriving at Quainton in 1970. Two other locomotives from Millom Haematite, David and Alexandra, both 0-4-0ST Barclay locomotives, are preserved at the Lakeside & Haverthwaite Railway.

Operating from Easter 1970, the locomotive gave valuable service during the formative years of the Quainton Railway Centre but inevitably, as with all working locomotives, an overhaul became necessary, and the engine had to be withdrawn from service.  During this time the loco became the property of the Quainton Railway Society.  The loco apparently needed some fairly major work to be done on the firebox. So it was cosmetically restored as a static exhibit and remained so until it became practical to undertake full restoration.  The locomotive was named Millom on preservation, after its place of work.

Recently Millom's boiler was sent to a specialist contractor who has confirmed that the boiler and firebox are sound. The boiler has been re-tubed and has had a successful hydraulic test.  Millom is to return to operation for the 2008 season.