Let's make Inland and other Interstate Rail work properly and genuinely shift traffic from road using modern, currently available, efficient diesel-electric locos and state of the art wagons before we go off into fantasy land (for us anyway) with electrickery.A good start would be to build Inland Rail with the route set up to have double track and electrification added at a later stage. Every cutting, embankment, crossing overpass and underpass should be built to double track width and with sufficient height clearance for OHLE to be added.
We cannot compare Australia with Europe so far as rail operations are concerned although it would be nice to start with Swiss punctuality.
Remember everything comes at a cost which someone, somewhere, along the way will want to recoup somehow.
To lock it in to a long term future of only being a single track line with diesels chugging along it is to
a) leave little room to handle the growth if it is more successful than expected,
b) invite questions as to why it is not being planned to be a success
c) leave people wondering if it should be built at all as it isn't sufficiently different to the existing situation of diesels chugging along a single track line.