The Walkers Ltd engines were all painted in a medium brown colour scheme with green lining on the footboards, and tender edge, and black smoke box and red buffer beams. The engines were nicknamed 'Brown Bombers' after the then world champion heavyweight boxer Joe Louis. These brown bombers differed because they were fitted with roller bearings and larger tenders. Also, a more streamlined cab and side windows for weather protection were fitted.
The workhorse of the steam era, the C17 locomotive being overall the most numerous class of Queensland engine, was also possibly the most versatile.
The C17 worked almost any train in Queensland, be it suburban passenger, goods train shunt or even hauling air-conditioned trains in western Queensland.
The main reason so many of this class were constructed was that it was the most powerful form of conventional locomotive that could run on Queensland tracks, regardless of the limitations of axle loading.