Abstract: A conveyor having a pair of fixed, transversely spaced side rails adapted to support a plurality of rollable articles for forwarding movement to successive positions each defined by a pair of vertical abutments having a pair of ramps extending forwardly and downwardly from their upper ends to the next successive position. A pair of transversely spaced, upwardly and downwardly movable article advancing members, having pairs of downwardly inclined article advancing surfaces and upwardly inclined article retarding surfaces between each successive position, is adapted on upward movement to raise an article above the abutments of one position, to cause forward rolling movement threreof on the advancing surfaces to a location above the next pair of ramps, and on downward movement to deposit the article on those ramps for rolling movement to the next position, the rate of that movement being controlled by the article retarding surfaces.