12 COMPONENTS FOR RAILROAD BRAKE SYSTEMS NAMELY; RETAINER VALVES; SLACK ADJUSTERS; [ POWER HAND BRAKES; EMPTY AND LOAD BRAKE SYSTEMS, NAMELY PROPORTIONAL VALVES, SENSOR VALVES, AND RESERVOIRS; ] ANGLE COCKS; BRAKE CYLINDER RELEASE VALVES; COMPONENTS FOR HEAVY DUTY TRUCK/TRAILER AIR BRAKE SYSTEMS AND FUEL SYSTEMS NAMELY; SLACK ADJUSTERS; GLADHANDS; FUEL TANK CAPS, GASKET AND LOCK ASSEMBLIES THEREFOR; AIR BRAKE LINES AND CONNECTORS THEREFOR; AIR TANK DRAIN VALVES; AIR TANK FITTINGS AND DRAIN COCKS; FUEL TANK SELECTOR VALVES; AIR CONTROL VALVES, INCLUDING AIR START VALVES, TRACTOR PARK VALVES, TRACTOR PROTECTION-CONTROL VALVES, TRACTOR TRAILER PARK VALVES, [ TRACTOR TRAILER AIR SUPPLY VALVES, ] PARKING BRAKE VALVES, TRACTOR PROTECTION-CONTROL VALVES AND CHECK VALVES