FP PayBus Series 2 (left of centre wildcard - they do say Railcar - singular)
Perhaps not so wild. One of the FP7-FP11 was set up as a dedicated railcar for the Bomballa line, and another got seating for when it carried Royalty! Oh, and there was that facebook poll in Feb 2013 run by Auscision for "what would you like us to make?", which they started the ball rolling with about half dozen suggestions of which one was "NSWGR Paybus".