Wow, Ben, I am so sorry to hear and see this! That is a very unhappy discovery!
I am curious to know- there is mention made of the zinc pest problem with various MTH/Atlas/Lionel past products; how about Sunset/3rd Rail/GGD? Their products are certainly pricier than the other major manufacturers. Have people experienced zinc pest problems with their products or is part of their higher pricing a better, more controlled manufacturing process?