Read the schematics of the 3-car and 6-car Comeng, Siemens and X'Trapolis trains and then come back with the platform screen doors. As in, the odds of the city loop gaining those useless things is the odds of Australia adopting Mandarin Chinese as its national language.
Get our first-world public transport problems out the way first:
* The City Loop is slowly crumbling and otherwise falling apart, not to mention Melbourne Central is possibly the worst underground station on the southern hemisphere. Mitcham comes a close second, as it takes around a minute to get from Mitcham Rd to the platforms despite the station itself, including a set of ramps leading to the platforms, being right at the edge of Mitcham Rd, blocked off by nothing more than a wire fence.
* The rail network is being slowly converted to non-gauge-convertible broad gauge concrete sleepers at a considerable cost, instead of progressively converting each line to standard gauge.
* As mentioned above, we still have specific train types stuck on specific lines, something which could be fixed in a heartbeat yet no-one can be bothered.
* Our classic W (and even Z) class trams are decrepit and being withdrawn at an alarming rate while the poster child Route 96 gets all the new trams (plus the Bumblebees, plus the D2s as well) while lesser tram routes/depots miss out again and again (Glenhuntly, Malvern, Essendon to name a few - an A class can hardly be considered an upgrade when it's replacing a clapped out Z1 since it's actually smaller; those platform stops all along the 70 and 75 are still a complete waste of time too since Camberwell has a 100% high floor fleet consisting entirely of A and B classes whilst D1s are wasted going at walking pace on the 72 since the timetable still seems to be designed around W classes, not to mention platform stops are next to nonexistent on the 72, or at least the Camberwell end). W classes should be green and cream and look spotless, not maroon with a dark roof with months worth of carbon deposits sprayed all over them like an unmodified Hitachi centre motor.
* The suburban bus network is a complete shambles with services running at any rate between 5 and 120+ minutes on any given day that may or may not include Saturday or Sunday and in any given direction but direct or even taking different directions but keeping the same route number (e.g. 737 going via Norton/Jesmond Rds instead of direct via Dorset Rd). Trains don't have Saturdays, Sundays and public holidays off or only run during AM and PM peak or run hourly with a 6:03PM finish, so why do suburban route buses? Even 9PM is ridiculous when trains and trams are running until 11PM-1AM.