Another piece of info that Mike hasn't added is that ARN147564 was configured as a "Prime Mover "A"", meaning that it was the truck intended to tow the Trailer "A", better known as the ZPI (Zone Position Indicator) Trailer.
There are several of these still existing, including one used as the Office for Corowa. You'll have to park it up next to the trailer at least once for a pic!
http://www.mapleleafup.net/forums/showthread.php?t=3459
http://www.mapleleafup.net/forums/sh...ad.php?t=24088
http://www.mapleleafup.net/forums/sh...ad.php?t=24089
http://www.mapleleafup.net/forums/sh...ad.php?t=20686