From the way the contracts are set up (sliced and diced north and south, civils versus ops), the players involved - Plenary is a very familiar name (they're involved with our next gen fleet of trains that will operate on the Melb metro tunnel, Sydney Metro fleet (pic already shown in this thread) and the Gold Coasts new tram line) - to the broad technical characteristics, you can see how globalised new rail line implementation has become.
Where 50 years ago there might be have been more noticeable quirks, these days, there's far more familiarities.
For instance, the 4 car, up to 5 car, possibly 100m platform stations is about the sweet spot that'll probably feature for the suburban rail loop here in Melbourne. Ontario line (capacity relief and expansion within a smaller geographical area) and the SRL (an orbital wrap-around to enhance an existing and continually upgraded radial network) are doing two different things, but it's interesting that many of the same players view their solutions as applicable to both.
Doubly interesting is that out of the 4 cities (Toronto, Melbourne, Montreal and Sydney) going down this path, Sydney (or more to the point, the NSW state government who has planning control) are aggressively pursuing active expansion / new rail lines with similar "metro" tech (as they now categorise it up there). The line that has recently been announced to connect to the new Western Sydney airport will be 4 car (the main metro line that's open and will be extended in a few years is 6-car - very AU suburban train-like) and I wouldn't be surprised look/feel is more akin to the Ontario Line despite it having an average station spacing of 4km (as it cuts through undeveloped areas atm).
I'd slot Montreal next to Sydney in this case because they appear to be now enthusiastically pursuing REM de l'Est which for all intents and purposes will most likely look the main REM under construction versus aggresively expanding their existing metro on the same scale.
And Melbourne & Toronto are dipping their toes in the water (OL and SRL example above) while also looking to augment existing networks / expand them too (in Toronto's case I'm specifically talking about TTC and GO, not just one or the other, in Melbourne's case it is the long list of level crossing removals and augmentations like Melbourne Metro and the mooted future cross-town connections still to come). Sydney's all but stopped enhancing its existing network - for now.
Apologies for the foreigner dumping in on this thread but I think closely watching what happens across the 4 cities will be a worthy exercise over the next decade - any academics on here? surely there's a thesis or ten in it.