>>1427023Good point on dual gauge tracks but I was not suggesting that they go any further than between Jacana then along the current suburban tracks on the Craigieburn line through to Southern Cross, track on which the trains will definitely be speed limited, but with proper scheduling will still end up much faster than swinging wide into Melbourne's West then coming back in. Leave the Albion-Jacana loop to freight. Or electrify it as part of a cheap airport link via Sunshine. Just do *something* about it.
The other problem I didn't discuss properly was overhead power. The good news is both Sydney and Melbourne use 1.5 kV DC. The bad news is that's considered really underpowered by modern standards. Other states have standardised on the more modern 25 kV AC. The high speed electric trains would then need to be dual mode or Sydney/Melbourne would need to get their act together about upgrading the overhead. Considering the size of their train fleets, I don't see it happening.
Then again, with plans to get rid of the Comeng within 10 years:
https://www.youtube.com/watch?v=uGhjxg2WRJ0and I'm guessing that the Siemens Nexas and Alstom X'trapolis were probably designed for 25 kV AC - then maybe the overhead could be switched over with a bit of effort.
