Thank you Graham for that info. It seems that parts of the WA trip by the Flying Scotsman have been lost to the mists of time...
Not lost - Some of us remember it well.
Flying Scotsman did return east from Kalgoorlie as part of a larger consist, but with only a few of the NSW cars - These cars were loaned cars from SRA NSW and were mostly supporting cars ie tanks, open wagons, crew car etc
The majority of the NSW passenger cars had to be purchased by Ian Willis the entrepreneur who had funded the visit of Scotty to WA. As SRA had no operational spare cars available of suitable capacity at the time, surplus cars were purchased by Ian and made fit for traffic for the the journey across Australia.
After the tour was over and Scotty had departed for the east, the remaining cars returned to Perth with Pendennis Castle and were used on at least one more run before Pendennis was returned to the Pilbara.
These passengers cars were then later purchased by a Pinjarra based member of Hotham Valley Tourist Railway and they were stored on a property in the area where most of them remain today.