The 1600 class were built as branch line locomotives. Two contracts were let of which the first was for twelve with a follow on contract for another six. The first batch were delivered between December 1962 and June 1963, with the others arriving between October 1963 and January 1964. A lengthy delay occurred before delivery owing to the first four being over the design weight. This resulted in numbers 1604 and 1605 being the first to enter service. All others were delivered after the weight problem had been overcome.
They were initially based at Alpha in Central West Queensland[1][2][3] and at Roma in South west Queensland. They were also used for shunting at yards around the state. Soon afterwards, all the 1600s were based at Alpha. The 1620 Class followed on from the success of the 1600s, and were used in the central and northern areas of Qld.
The class was withdrawn in 1991.
Five have been preserved:[2]