I checked with a friend who went back to work there about a month ago. The parts situation is the way it is because the factory that made those locomotives is either closed or just now returning to production (after a year and a half). They really tried to satisfy their customers by making replacement parts available, but simply put, they are running out. During their recent move, they might have found some of what you needed. Extra parts are hard to get. They might negotiate to get 100 extra wheelsets, and the factory might be willing to tack that onto a batch of complete products, if they are produced. Virtually nothing had been produced for a year and a half. So no parts.
Bill Kepner