Not that there would ever be a positive business case to justify a “very fast train” between Sydney and Melbourne, especially given the inordinately expensive construction costs in Australia.
This below table shows why there will never, ever, ever be such a train in Australia. The return on investment on the Qantas Chairman’s Lounge (which all Federal MPs and Senators get invited to), plus all those free upgrade is clearly not small.
This table by the way … Top 10 Highest Revenue Routes.
Note the top earning route is between New York and London and the 3rd top earning rout is between London and Dubai. On a revenue per kilometre basis or a revenue per hour air time, Qantas is out there by an oligopolist mile.