The breakers on my Lionel 180 watt bricks trip for any reason. They are fast. Sometimes too fast.
The breakers or whatever's inside my Z4000, have not tripped. They don't protect enough.
Install inline fuses after the Z4000. (I have them with the Lionel bricks too even though they have never blown.)
I have popped many fuses. Although it's a pain, it's better than many other things popping.