Circa 1950, the New Zealand Railways Department placed an order for 25 DSB shunting locomotives. They were built by the Drewry Car Co. between 1954 and 1956. The first three DSB class locomotives were commissioned in August 1954. The DSB are a larger and more powerful locomotive than the DSs and DSAs, and were used all over New Zealand. By the end of their lives 12 DSBs were repainted in the "International Orange" livery. Three were purchased for industrial service with DSB 1153 going to New Zealand Milk Products (later subsumed into Fonterra) to shunt their Whareroa milk factory, 1194 to Pacific Steel at Otahuhu scrap plant and 1221 to Avon Engineering at their Kamo plant. DSB 1221 was sold in 1986 while the other two were sold in April the same year. In 1963 all Drewry builds were re-engined with Caterpillar D343TA replacing their National M4AA7 which they entered service with. This increased their power output from 195 kW (260 hp) to 293 kW (353 hp). In the 1960s the New Zealand Railways placed an order for three more DSBs. These three were built by Mitsubishi Heavy Industries. As of July 2014 only one has been preserved, DSB 313 was purchased in January 1991 by the Mainline Steam Heritage Trust for shunting uses at their Parnell depot. also Dsb 321 once owned by Kamo still remains there today but it is in parts, 
ORB 2 shares a similar operating history to ORB 1, but was withdrawn in 1990. Stored in Wairio until 1992 when it was purchased by Reid McNaught for Steam Incorporated. It was then sold to Richard Gibbard in the early 2000s and is still in service for shunting uses by Steam Inc..