Wouldn't the only benefit of converting the Card to Superliners be to increase capacity? 'Cause it's not a very popular or high demand train, and capacity wouldn't DRASTICALLY increase by using Superliners. Additionally, switching Cardinal equipment and therefore accommodation types just adds to list of possible customer complaints (for those already booked). While most people probably won't care about it, some might complain and ask for some kind of compensation if the equipment is different: "I DON"T HAVE A WINDOW FOR MY ROOMETTE UPPER BUNK! I WANT MY MONEY BACK!". That example would be ridiculous and Amtrak obviously wouldn't do that, but my point is that the more stuff they change, the more complaints and hassle Amtrak has to deal with.