UPDATE: Thanks to Leigh for sharing some photos from his visit to the Australian War Memorial:
Original Post (03/19/.2011) Greg’s found these image at the Australian War Memorial in Canberra, Australia. A little more research yielded a few stories and additional pics at the Australians-at-War website. You can see other Jeeps on rails used in Australia at G503.com.
looks like they used truck split rims, by cutting out the centers and welding in ones with the correct bolt pattern