Railway switch mechanism

Claim 1

IN A POWER OPERATED SWITCH MACHINE FOR THROWING SWITCH POINTS BETWEEN INITIAL AND SECOND LIMIT POSITIONS AND OPERABLE, UPON FAILURE OF THE SWITCH POINTS TO COMPLETE A THROW TO THE SECOND LIMIT POSITION, TO RETURN THE SWITCH POINTS TO THEIR INITIAL LIMIT POSITION; A REVERSIBLE ELECTRIC MOTOR, A HYDRAULIC PUMP DRIVEN IN OPPOSITE EXTENDHYDRAULIC PISTON ADAPTED TO BE DRIVEN IN OPPOSITE EXTENDING AND RETRACTING DIRECTIONS BY HYDRAULIC FLUID FROM SAID PUMP, ROTARY CAM MEANS ENGAGEABLE BY SAID PISTON AND ADAPTED TO BE TURNED IN OPPOSITE DIRECTIONS BY SUCCESSIVE EXTENSION STROKES OF SAID PISTON, CONNECTING MEANS OPERATIVELY CONNECTING SAID CAM MEANS WITH THE SWITCH POINTS TO MOVE THE SWITCH POINTS BETWEEN EITHER LIMIT POSITION UPON A PREDETERMINED AMOUNT OF TURNING MOVEMENT OF SAID CAM MEANS IN ONE DIRECTION OR THE OTHER; ELECTRICAL CIRCUITRY FOR SAID MOTOR INCLUDING A STARTING CIRCUIT, DETECTING MEANS IN SAID CIRCUITRY TO DETECT ARRIVAL OF THE SWITCH POINTS AT THE SECOND LIMIT POSITION DURING AN INTENDED THROW OF THE SWITCH POINTS AND EFFECTIVE THEREUPON TO REVERSE THE MOTOR TO CAUSE RETRACTION OF THE PISTON THEREBY CONDITIONING THE PISTON FOR THE NEXT EXTENSION