The first batch of fifteen Q class locomotives were purchased from Dübs and Company, Scotland to replace the unsuccessful N and O class locomotives on the South Australian Railways "Intercolonial" hills line workings. With the new Q class locomotives being able to haul moderate loads on offer, these locomotives performed very well and the SAR ordered a second batch from the local James Martin & Co. Following the introduction of the more powerful R class locomotives on the southern line, the Q class was put to work on interstate trains from Murray Bridge to Serviceton as well as the northern lines.
These locomotives easily reached speeds of 60 mph (97 km/h), which was required to run these services. They were often seen "double heading" with the S class locomotives on express passenger trains. Q class locomotive No. 90 worked local trains between Murray Bridge and Tailem Bend, and in its final three years of life it spent its time as shunting locomotive at the Islington Railway Workshops.[2]
