Not sure if this could be feasible, but NSW Trainlink are about to have a few surplus Endeavour sets with the introduction of the new regional D sets. Would it be worthwhile, as an interim service, for DTMR/QR to acquire a few to run between Flagstone and Salisbury?
Obviously, a few platforms would need to be built, but minimal new track (maybe passing loops at platforms).
I realise this isn’t an ideal outcome, but it would be a relatively quick/cheap way to get some service on the line.
Btw I have no idea about the lifespan of Endeavours, nor their accessibility. I hope others might.