I'd be wary of any unsolicited proposals. They're usually biased in favour of the proponent to maximise profitability and don't necessarily consider the broader community impact. I'm afraid I don't have a lot of confidence in the ability of the bureaucracy and its advice to the government to resist the lobbying of the proponents with the promise of a privatised model, which may or may not be feasible.
I'd prefer to see a wide ranging community consultation process to establish the best option and THEN call for expressions of interest from the private and public sectors. You don't put the cart before the horse.Second Illawarra rail line makes the cut