Sharing between MARL and SRL may well be a poor 2nd choice, but it all comes down to cost.
SRL priced at $50B all up is very tight and will need to make hard choices about efficient use.
Waiting until 2050 for your ideal is not going to be acceptable.
The pressure is on for Wyndham Vale and Melton now, which has been rolled into the MARL business case. How far those plans go in delivery will be interesting.
Bendigo and Seymour(SG) are all capable of Sunshine stopping now. Just hasn't been any appetite yet. Even Seymour BG could go via Albion to relieve the Metro, but no takers so far.
JohnMelton will and would stay on the Metro tunnel.
WV can be electrified, initially via Metro tunnel. As paths are needed, can be converted to SRL approaching 2050 like the Bankstown conversion in Sydney. What's done now need not lock in stone for 100 years.
Im not talking about stopping Bendigo and Seymour trains at Sunshine right now. I'm talking about routing them Sunshine - Airport - Gisborne/Wallan as a stopping pattern, with MARL trains running in between.
Agree that Regionals should be using the track capacity that will be available thanks to MARL. If we put aside the major issue between the city and Sunshine for the moment. The new track between the Sunshine and the Airport will only be used by 3TPH, not really bang for your buck. If Bendigo & Seymour get added, that brings it up to 9TPH. Airport to Wallan & Gisborne is all Greenfields. You could build both connections for a billion.
Rail Projects Victoria, as with many others, have already said there will not be enough capacity in MM1 for Sunbury, Melton & WV. One is going to miss out. If you spark and run WV services via RRL, we've got mixed traffic again with Geelong and Ballarat taking up paths for WV.
Unless the government grows a set and does it all properly someone is going to miss out. WV or Melton end up with substandard services waiting another 10 years. Airport get shoved into MM1 takes up TPH for Sunbury. Melton gets put in, its a balancing act of capacity as population grows in both corridors.
For the $17 Billion that is currently on the table from all parties the state could revolutionise public transport for not only the western suburbs but western Victoria. Let Airtrain have there tunnel, they are paying for it and they will suck airport commuters dry for decades. Who cares. Government gets a shinny brand new tunnel. The rest of the money could be used to build the regional connections to Wallan and Gisborne, Quad Melton to Sunshine and spark it, Quad to WV to keep Geelong seperate from the sparked RRL. Melton & WV have growth for decades. Regional services are 100% separated from Metro traffic no conflicts, DOT/PTV can ramp up capacity as needed over the next 30 years.