Frank:
If I’m understanding your question; your easiest option for automatic uncoupling of cars is the uncoupling track. I’ve seen articles where folks have built their own but, they are using salvaged Lionel parts applied to track systems such as Gargraves or Atlas. I believe you are using 0-27 or 0-31 tubular track based on some of your earlier posts so, buying Lionel uncoupling tracks would be the way to go.
Curt