How did they arrive at the station locations in the first place?
Pages 24/25 in the pdf explains why they chose those particular station locations.https://bigbuild.vic.gov.au/__data/assets/pdf_file/0006/325572/Suburban-Rail-Loop-Strategic-Assessment.pdf
My comments in the other thread related to the need for a business case for this project. Do we really need one considering it will be publically owned and managed and the business plan for the loop would have been thought through?
Yes, we do need a business case for this project. That's one assumption to claim it will be publically owned and managed. It's likely to have a Private Public Partnership (PPP) involved, to reduce the burden of the cost to taxpayers. But it isn't whether it's public or not that determines if the project needs a business case.
All projects that cost above 100 million dollars, needs to be assessed thoroughly to see whether this project is worth paying for.
And yes while the 10 billion dollars have been pledged prematurely, it will only be transferred after the business case is delivered. Only then we can see more information about the project and how beneficial it would be to the state.
In the meantime, railpagers will speculate on the benefits and costs. Also may foam about what route they would like. But at the end of the day, the business case and thoroughly assessing the project through evidence-based research will determine and refine the proposed project and see how to make this project a successful investment. I would argue that other major and minor transport investments that should be delivered before the opening of the full SRL route.
Major projects such as the Melbourne Metro 2, Add capacity on the Dandenong line & electrifying intercity regional routes.
Meanwhile also minor investments such as improving the existing tram network, improve bus routes and coordination, improve the frequency of services across the network and those really worthwhile tweaking to get most out of the existing infrastructure.
But nevertheless, a start on an orbital rail route will have merits, especially the proposed South East section where it's likely to be well utilized and be useful to densify the eastern suburbs. And while many argue a mixture of better orbital light-rail and buses are the solution, they would never be any quicker and transformative than heavy-rail/metro.
Anyways I hope this answers your question.