On the train the car attendant in both sleepers and coach ARE REQUIRED to bring food to the patron if requested.
MY wife has spinal cord injury and prefers the train to the plane. In a sleeper the attendant is very attentive.
At Chicago they have a motorized cart to take her from the first class lounge to the train and the attendant will get her to her roo which is 3 steps. If she cannot climb the steps the have a little device to lift her the 3 steps. After that with the handicap bedroom everything is on one floor,
Couple of links to peruse
http://www.amtrak.com/accessible-travel-services
virtual tour of sleeper including handicap bedroom found at
http://www.amtrak.com/servlet/ContentServer?c=AM_Accommodation_C&pagename=am%2FLayout&cid=1241210576085
meal service for disabled at
http://www.amtrak.com/servlet/ContentServer?c=Page&pagename=am%2FLayout&cid=1241267362161