@jakecoppinger don't know much but it sounds great. I think there has been a perception that the travel time must be competitive with flying (including airport access etc) to get mode shift on the route, thus needing to be HSR. But that may not be the case with increasing desire not to fly or drive.
I used to be one of those work travellers doing day trips to Melbourne and I think a 6 hour train the afternoon before would have been quite an attractive option.