A continuous distributor consisting of a steel open-topped box filled with stone dust. Resting on the surface of the stone dust is a steel plate 1/4 in (0.64 cm) in thickness fitting loosely into the box and perforated with holes 3/16 in (0.48 cm) in diameter. The plate is connected by a series of chains and levers to a lever between the rails on either the loaded or empty side of the roadway. Each tub passing along depresses the lever and causes the steel plate to be lifted. A counterweight restores the track lever to vertical and the plate falls, causing a puff of stone dust to be ejected through each hole into the ventilating current. Thus stone dusting keeps pace with output.