Imo, SydneyTrains and MelbourneTrains have enough activity to justify keeping. BrisbaneTrains is pretty much dead, so we could either just leave it, or run a poll and if everyone was in agreeance, leave a redirect notice to this new AusTransport community and ask people to post their instead

As for the potential crossover between Melb/Syd and AT, I would view it like how there’s Sydney, Melbourne, brisbane, etc, communities as well as an Australia community. Usually things specifically related to cities or states with their own communities would go in those communities, but sometimes whoever’s doing the posting thinks they’re significant enough to be relevant to the Australia wide comm, too