This sounds possible. GNRS did run a Met ballast train with its own crews
a few weeks ago. For ballast trains, they're going to need more than a few
T's. Probably a few first series X's or similar.
Could it be that the X's on hire to NR for Melbourne - Long Island steel
trains are to be sold to GNRS? Could the C's have been sent from Junee to
Melbourne for conversion to broad gauge to haul steel?
Cheers
David