This interesting locomotive was built by Baldwin Locomotive Works, Philadelphia (builder's number 41242 of 1914 ^a) as one of two 4-6-0 engines (Nos. 4 & 5) supplied to BHP Whyalla for use on iron ore trains from the mines at Iron Baron to the port at Whyalla.  It represents a classic Baldwin Locomotive Works product with typical features - bar frames, slide valves and rugged, practical construction. ^b

In time Nos. 4 & 5  were superceded on iron-ore duties by larger heavy-haulage 2-8-2 locomotives, also supplied by Baldwin Locomotive Works.  The entire steam line haul fleet was replaced by diesels in 1956.  While No.5 and the impressive 2-8-2s were scrapped, 4-6-0 No.4 was retained for miscellaneous steam plant duties until finally condemned in 1969.

BHP No.4's tender found further use at Whyalla as a weedkiller wagon, and the tenderless locomotive No.4 was donated to the Australian Railway Historical Society (ARHS) South Australian division.  BHP No.4 was originally displayed at the former Mile End Railway Museum, where it was paired with a spare SAR Y-class tender.

The remains of the original Baldwin tender were subsequently retrieved from Whyalla and restored in the 1980's. (Inspection suggests a new welded tank was created and paired with the original chassis.)  BHP No.4 is now exhibited at the excellent National Railway Museum, Port Adelaide.

(As an aside, the spare Y-class tender formerly paired with BHP No.4 was relocated to Quorn on the Pichi Richi Railway, where it is expected to be used for the new-build Z-class 4-4-0 project.)