There were two types of Twin Unit P.R.R. diners , first off these cars were not articulated, not like some SP and UP cars which shared a center truck. They were just semi permanently connected by a draw bar coupling arrangement. The dining room cars were pretty much identical except for interior color schemes, cars that were used in daytime service between New York and Washington had kitchen cars with a bar lounge area in the space occupied by the crew dormitory space on overnight cars like Broadway. On one of my trips back east with my parents to visit grandparents, I rode on one of these day trains, that is how I know of the differences in the kitchen cars. Nate Goodman (Nato).