Abstract: A mechanically cleaned bar screen or bar rack is disclosed for removing debris from water and wastewater treatment facilities which comprises a frame with housings supported thereon and a bar rack and dead plate. The apparatus is supported on the ledge of the sluice of a water or wastewater treatment facility tilted backward at an angle of about 0.degree.-30.degree. with the bar rack submerged in the flowing stream of water. A carriage carries a pivotally mounted rake assembly with a rake engaging the bar rack. The carriage is reciprocated along a guide rail by motor operated lead screws which extend through rollnut assemblies supporting the carriage. At the top of the traverse of the carriage, the rake is swept by a wiper to remove debris to discharge down a chute for pick up. The motorized drive system is totally enclosed. The motor and gear boxes are stationary and do not travel with the rake carriage. Corrosion resistant materials are used to ensure long life.