The Turboliners? They're not compatible with any other Amtrak equipment, are older than the Amfleet cars, and have been sitting for years; They'd need a lot of work to ever be roadworthy again. There is also the matter that the trainsets were parked for legitimate reasons all those years ago. Technically you could haul the trains around with a locomotive (once repaired), but I believe there were some safety concerns with doing so (somebody here probably knows the details).
As the last Amtrak turboliners remaining, ideally one set should go to a museum.