All die-cast will eventually turn to dust. But some plastics will remain in landfills for thousands of years! Major shout-out to Harry Henning, whose efforts have probably put more crumbling toy trains in O and Standard Gauge back on the rails than anyone I know!!
That being said, has anyone reached out to Dennis Mashburn (KD Castings, Abilene, TX) ? He's a 2-rail O Scaler and does small-run brass castings with a foundry on his property. I've been to his house and he told us all about shrinkage, lost wax and plastic masters, etc. If you have a good part, even if it's plastic, he might be a guy who can do it in brass. And in multiples! (I've seen some of his stuff fresh on the sprues.) Brass is very permanent. It doesn't disintegrate like die-cast so you won't have a repeat of this problem. Of course it would have to be painted.
I can't speak for Dennis, I don't know what his current workload is like or what he would charge. Just trying to take some of the repetitive production load off of Harry and give people a metal option if they really want one.
