However, with further reflection, I decided that the Casula Hobbies K truck could be adapted. I glued several strips of styrene to increase the size of the base (see photo opposite), fixed the completed tank to the base and then fitted the modified K truck sides around the tank. It was also necessary to adjust the wheel mountings to ensure the correct height above the track.
Painting and weathering will follow but this has been an exercise in dimensional variability as can be seen from the three versions in the photo opposite, an original Casula Hobbies, an original Austrains model and the modified K truck mounted water tank. I suppose as long as I make sure that they don't appear in close proximity to each other, then differences are not too obvious.