The reversing problem can mostly be adressed by setting each side of the double track to one way with signals.
This will not stop the trains reversing and gumming up the the network. My point is that the reversal should not happen!
I am also aware that trams can behave in the most peculiar way when the road network is modified. The difference is that the the trams sort themselves out after a short time without any need for player intervention and thus do not cause any major problems. The trains have to be corrected by the player, when they notice the problem, usually when a highly profitable line start loosing money.