Wow, that's quite the crossover system just south of Central! Kinda funny how little attention I pay to Sydney relative to Melbourne, long an inspiration for both trams and same kind of s-bahn-esque, quasi-metro rail network I keep mentioning.
I've been reconnoitering fun areas like that around
Clapham Junction,
Hamburg Hauptbahnhoff, and
Oslo Central trying to make sense of all the crossings, when to use 4-track rail, 2-track rail, single or a wider variant, and attempting to apply the lessons to a smaller scale city. For as long as I've made serious efforts at realistic cities I've inevitably kept expanding the size and scope (generally in order to justify excessive freeway networks and other transport) of those cities; this time I'm trying to set a very firm upper limit at approximately a million metro area and hoping to substitute idiosyncrasy for excessive redundancy and disciplined realism focused on mass transit for the old super-interchanges (me being me there will still be super-interchanges

but lane counts will be down, interchanges more autobahn than Texas-Toronto-traffic-tantrum, non-motorway arterials more common, etc.
A weird quality of rail mass transit around this size of planned city is it seems to rapidly increase or decrease in importance and complexity and ridership, on average, within the space of a couple hundred thousand peeps, suggesting there might be some kind of "critical mass" point around there (of course dependent on a city's geography, alternate transport options, etc) that affords the scale and service frequency sufficient to create a positive feedback loop of increased ridership. My hope is to replicate a system on the relatively small end of size yet big enough to feature some of the overpasses and stations and complexity I always enjoy--but firmly avoid my usual size inflation.
This is a rough version of my rail plan (rgb topo map with sea dark blue and pink squares size of large city tiles) with terminal central station near center and black representing commuter and intercity rail. The light red represents hypothetical metro/U-bahn/light rail service. In addition to and adjacent to the branching lines east from central I plan a series of railyards and depots, effectively constituting a 4th branch in some sense.

Closest probable example is G�org, albeit with less commuter/T-bahn relative to longer distance
https://goo.gl/maps/okM5mQ9wdypfvUSeAHelsinki is another main inspiration
https://goo.gl/maps/7JD6PK73GyPi3iQP8It's a bit of a weird case in that there's not many branches and that the metro, running primarily east-west from central station and south of the commuter railways, functions very similarly to the commuter rail network.
Where and whether to include grade-separated rail crossings in the vicinity (few km) of central is main question of the moment
