 The X class was a development of the earlier C class 2-8-0 goods locomotive, designed to be gauge convertible from to in the event of the Victorian Railways network being converted to standard gauge.The C class, with a narrow firebox between the frames, could not be easily converted.The X class retained the same cylinder and driving wheel dimensions as the C class as well as its valve gear, but introduced a much larger boiler and a trailing truck behind the rear driving axle.