Drewry 2248 /1947 was built for the Ohai Railway Board as their No. 1 and was joined by sister engine No.2 in 1957 effectively dieselising the Ohai Railway Boards Line.
ORB No. 1 is the forerunner to the NZR Ds class of locomotive which were first put into service as heavy shunters during 1949.
In 1968 Ohai Railway Board replaced the two Drewry locomotives with two new locomotives built by Mitsubishi Heavy Industries. No 1 along with No.2 were dispatched to the State Mines railway between Stirling and Kaitangata in Otago.
In 1974, both locomotives once again moved this time to Rotowaro in the North Island, where they both finished working in 1986.
Both ORB No.1 and No.2 were obtained by the Bush Tramway Club in 1986 and stored for a number of years until they were both disposed of. Bruce McLuckie purchased No.1 and Rotorua Ngongotaha Rly Trust eventually obtained No.2.
(items in italics relate to ORB No.1)
1947 – Drewry works number 2248/1947 was built for the Ohai Railway Board as their No 1. Locomotive entered service hauling freight and passenger trains.
1947 - Whakatane Board Mills orders a similar locomotive (maker's 2258/1947) for use over the Whakatane Board Mills, Matahina Tramway, bringing logs back from the Matahina area over the Tramway to the mill via the NZR Taneatua Branch.
1949 – NZR orders a batch of four similar Drewry 0-6-0 DM locomotives which they call their DS class. locomotives arrived in Wellington in 1949 for evaluation. All four Ds locomotives were put to work in the Wellington railway yards immediately after their entrance into service. The Ds class eventually totals 16 locomotives.
1951 – Whakatane Board Mills orders a similar locomotive (maker's 2489/1951) with two diesels the ex-NZR 0-6-2T tank locomotives FA 41 and FA 250 are displaced.
1953 – NZR staff photographer took a series of photos of the ORB No.1 in service.
1957 ORB No.1 is joined by sister engine Drewry 2585/1957. The arrival of ORB No.2 displaces steam on the railway and the steam engines are only held for stand-by duties.
1968 – ORB No.1 and sister locomotive No. 2 are both transferred to the state mines department railway between Stirling and Kaitangata in Otago.
1974 - ORB No.1 and sister locomotive No.2 are both transferred to Rotowaro near Huntly in the North Island.
1986 - ORB No.1 and sister locomotive No. 2 are withdrawn and sold to the Bush Tramway Club. The Bush Tramway Club transfers both locomotives to their depot at Pukemiro Junction on the former Glen Afton Branch. Some work is done on the locomotive including dropping the wheel sets so the wheel profile can be machined.
2005 – ORB No.2 is sold to the Waikato Railway Heritage Trust (Wallis Family). This separates the locomotives for the first time in 48 years.
2011 – ORB No.1 is sold to Bush Tramway Club member Bruce McLuckie.
2013 - ORB No.1 is offered for sale to the Rimutaka Incline Railway Heritage Trust. The Trust begins fundraising for the purchase and transport of ORB No.1.