35 engaging the inner surfaces of door retainer rail 19 adjacent the rear edge of the door and in longitudinally spaced relation therewith the door mounts a pair of bearings 37 and 39 near its bottom and top edges respectively and a vertical shaft 41 is rotatably journaled in bearings 37 and 39 and projects therefrom below and above the door thrust collars 43 and 45 on shaft 41 underlyingly engage bearings 37 and 39 respectively at its lower end shaft 41 mounts rearwardly extending bottom operating crank 47 which extends parallel to the car side when the door is closed and is pivotally supported at 49 on a roller carriage 51 rotatably mounting rollers 53 resting on track 15 the sides 53 of carriage 51 depending below the top of track 15 and guidably engaging the sides thereof at its upper end shaft 41 mounts rearwardly extending top operating crank 55 on the outer end of which is journaled roller 57 which is received between the inner vertical surfaces of door retainer rail 19 from the foregoing it will be evident that the door can be opened by rotating shaft 41 counterclockwise 90 u00b0 thereby moving cranks 47 and 55 from the closed door position parallel to the car side wall to an open door position normal to the car side wall and thus causing the rear end of the door to move transversely out of the opening and then moving the entire door rearwardly as front carriage 25 and front retainer roller follow the outwardly tapered front.