An operating mechanism for sequentially opening and closing hopper discharge door is provided. Longitudinally extending gates are arranged in pairs and are suspended from the hopper by hinge links at one end and by an operator arm located near the center of each gate. A hopper-mounted rotating link is attached to one operator arm and a hopper-mounted bell crank is attached to the other operator arm; both the rotating link and the bell crank are interconnected to sequentially operate the doors. A power cylinder and linkage are connected with the bell crank for automatically opening and closing the doors.