Dave - I still think you should ship it back to Precision Scale to fix. Not only is it new, but I had no similar problems with my K-28. We can take shots in the dark here regarding weight distribution problems, broken suspension springs, etc., but they built the thing and not only know how it should be, but also exactly where to look to find and correct the problem.
I know it's disappointing to have to ship back a brand new locomotive and wait for its return, but in the long run, you'll most likely be happier. MHO.