 Dynamometer car tests with R 707 showed the locomotive was able to develop approximately 1,590 drawbar horsepower () at , roughly equivalent to the 1,605 drawbar horsepower () generated by a conventional R class locomotive burning second grade Lithgow black coal.However, comparative tests also demonstrated that R 707 also achieved considerably higher efficiency, capable of consuming 1.5 tons less coal on the Melbourne to Bendigo round trip hauling a 350-ton trailing load, despite the lower calorific value of brown coal than the Lithgow coal.While the PBC locomotives performed well, the expense of installing storage and handling facilities became increasingly uneconomic with falling prices for fuel oil and the success of diesel-electric traction.