There is another question here. How the hell did the French build 300km of high speed track, going through central Paris, for only 10 billion dollars? If Australia could do that, the cost benefit analysis on Melbourne, Sydney and Brisbane would look very different.
Melbourne to Sydney is worth doing now, though it's a close thing. But the benefits come as time savings for rich businessmen, and Australia told them that if they really wanted it they could pay for it themselves.
They really need to build high speed rail across the east coast of Australia. We've talked about it in this country for so long and yet nothing is happening.
The problem is that it will cost 100 billion dollars (!), and it really isn't clear that it's worth that much. That's where the French seem to have some magical advantage.
Melbourne to Sydney is worth doing now, though it's a close thing. But the benefits come as time savings for rich businessmen, and Australia told them that if they really wanted it they could pay for it themselves.