What I should have said also was that I had a crash to desktop just before the problem began - lost about a 1/2 hour of work. The result was two routes with the same name which is why I wanted to do a "save as" in the first place.
After archiving the newest route X and the latest session, I did as you suggested and the save worked with a new route name but my session was reset. So I deleted the new route and tried the "save as" with a new route name and the session came along for the ride and now it works just fine.
Anyway, your suggestion ended up solving the problem although not in the way I would have expected. I do hope Auran fixes theses issues, especially the problem of two routes with the same name, which just should not happen. And you often can't delete them when that happens, either in Trainz or CM - all you can do is disable in CM apparently. So I have a half dozen disabled routes just taking up space.
Thanks again.