Cabin Cars, (caboose, hack, van etc.), were set up to operate in either direction, either as the last car in a train, or the leading end in shoving movements. Bay window cabins had reversible seats, in cabins equipped with "Gig Tops', (Cupolas), they just rearranged the cushions for the direction of movement. One end was usually designated the A end, the other obviously was the B end, but there were handbrakes and conductors back-up valves on both ends. There was also a conductor's valve in the center of the table, at the stove end.
The last assignment I worked on, with a fully equipped Cabin car, was the Linden, NJ Local, WJLI26, almost exactly 20 years ago. Atlas actually did a model of it, painted as the Philadelphia Division CQI (Quality) scheme.
Boris