I think I know how to solve Melbourne.
I just solved Bathurst last night Here’s a spoilerish account:
Having to get 99t of push bikes to Bathurst is a tough problem, because car yards can only hold 54t. If you back up two double trucks to Paramatta, they’ll each end up with 27t. That’s just enough to get Bathurst into the yellow on the first delivery, but not enough to complete it. You have to get two full doubles to Bathurst at the same time, plus two dump trucks. That gets you 96t, which is enough.
So the first problem is filling two doubles up at Paramatta. And the way you do this is to get the car yard at Homebush up to level 3, fill it with push bikes, and then, while the doubles are loading at Paramatta, send two dump trucks delivering push bikes from Homebush to Paramatta. The dump trucks unload faster than the doubles load, but it’s OK, all the cargo will end up on the doubles.
Then, when the doubles are about 2/3 of the way from Paramatta to Bathurst, you launch two dump trucks from Homebush, and they all arrive at Bathurst at more or less the same time.
I suspect that solving Melbourne is going to involve a similar approach, only using mining trains. Even if you can’t get a mining train into Melbourne itself, you can build a car yard on the main road. Fill mining trains up in Paramatta one at a time and send them southwards. (Of course, since each mining train can hold 200t of push bikes, you’ll need to fill one up, turn it off, and then replenish the push-bike supply in all the car yards in Sydney before you can load up the second.) Once you have 400t of push bikes on two mining trains, get them as far south as you can, bring all your goddamn dump trucks south, and then start unloading a mining truck into your car yard as you fill up dump trucks and shuttle them to Melbourne.
I think that’ll load the 400t of push bikes into Melbourne faster than Melbourne can eat them.
I was going to test out this proposal by buying a mining train (now that I’ve discovered where they come from - also, there’s a broken road up there that takes 2000t of asphalt to fix). But I discovered this morning that instead of having $2.2 million, my save file now has only $75K.