Probably the most cost effective / speedy solution for Superliner replacement would be to have Siemens run variants of the Venture designed to replace the Amfleet I on the NEC:
A coach car along the lines of the Amfleet II;
A cafe car (perhaps just extending the run of those for the NEC);
A diner; and
A sleeper.
Optional would be some type of single level SSL and (dreaming) a slumbercoach or other premium coach service.
Since these are using the same body shell, FRA approval should not be difficult to obtain. And at the end of the day (decade) Amtrak will have almost all its equipment from a single supplier.
A coach car along the lines of the Amfleet II;
A cafe car (perhaps just extending the run of those for the NEC);
A diner; and
A sleeper.
Optional would be some type of single level SSL and (dreaming) a slumbercoach or other premium coach service.
Since these are using the same body shell, FRA approval should not be difficult to obtain. And at the end of the day (decade) Amtrak will have almost all its equipment from a single supplier.