The Alaska Railroad built 30 Double Door box cars from troop car box cars.  The two doors covered a single 13' 8" opening on each side, which allowed fork lift loading
of 4 x 8 foot pallets of sheet rock, plywood and other building materials.  These were equipped with bettendorf trucks and used in interchange via barge service resulting
in lots of rust weathering from salt spray.  With so much of the car side removed, reinforcing was done with a 10' channel section welded to the bottom edge of the car between the bolsters.