The idea has come up before, and it gets all sorts of negative reactions. One problem is that Superliners cannot go into Boston nor New York, so there goes some ideas that have been put forth. Although not an insurmountable situation, the SW Chief and Zephyr would require a back up move out of Chicago Union Station to continue east of Chicago. They have backed into CUS in the past when arriving from the east, but not sure if they still do. Run through would be an easy matter, though, for the Empire Builder. The best chance for coast-to-coast service was the National Limited to St. Louis, and continuing on the Texas Eagle/Sunset route to L.A. IIRC, some of the rail has been pulled up between Pittsburg and Indianapolis, so that is no longer a possibility..