Hello Frank. Greetings from Fairfax Station. Haven't seen you post in awhile. I am having problems following the above post.
You use the term "heavy short." I assume you mean a sort where the limiting feature is the internal resistance of the transformer. Not sure why it makes a difference if the short is heavy or "light."
I have Powerhouse 180 on my layout, which has a very fast-acting resettable breaker. Are you saying that this can't protect the circuit from a heavy short?