Tearing out the doors, replacing them with trainlined automatics might be costly, or even impractical, depending on the space in the walls at the doors, and the wiring involved. The fact that the cars are 30 years old is a factor. AM-2 and Superliners are manual I believe, it just makes them less suitable for use on routes with high platforms, lots of passengers getting on and off, and no coach attendants (think NER/Empire/Keystone) since a crew member has to go open and close the door. PITA on a train with just a Conductor and an AC