A railroad hopper car discharge gate assembly has first and second elements arranged in vertically stacked relationship relative to each other for controlling discharge of material from a hopper car. First and second drive mechanisms move the first and second elements, respectively, between closed and open positions. A lock assembly including first and second locks serve to maintain the first and second elements, respectively, in a closed position. The gate assembly also includes a mechanical system for positively removing the first and second locks from a locked condition relative to their respective element upon rotation of either drive mechanism. A method for controlling discharge of material through an opening defined by the railroad hopper discharge gate assembly is also provided.