Just for curiosity, here is the scrapyard where seems to exist two, maybe three of this cranes. Public online images from googlemaps satelite and street views.
Its located in Lia St, Coober Pedy, SA 5723, Australia
Note, in the left rectangle is the US6 crane truck, as shown above, and from the street views, appear to exist another one, with a boom extension, in a darker colour (and not with the white painted main structure). On the right, there is the yellow one viewed earlier too.
Source:
https://www.google.pt/maps/@-29.0101.../data=!3m1!1e3
The one in Wilson's Steel, is seen on the google street view too, and it looks that it could be more than one too, as the main boom look to have the base frame sheeted over, and not opened as in the photo above:
https://www.google.pt/maps/@-34.2076...UPWfthWlOA!2e0
In a note, by viewing the larger US6 crane truck photos, it looks that there is a vertical power shaft, to operate the winch crane, in the center of the crane/truck attachement structure.Where it is connected? On other trucks, like the GMC, and the CMP C60X, the crane attachement is forward of the rear wheels... In this truck it looks to be over the rear wheels suspension center.