Railroad switch machine

In a high-speed railroad switch machine for throwing switch points between initial and second limit positions, a uni-directional electric motor, a hydraulic pump driven by the motor, a hydraulic cylinder including a piston, a four-way, two-position hydraulic control valve adapted to supply hydraulic fluid to the cylinder such that the piston is alternately driven in extending and retracting directions, rotary cam means engageable by said piston and adapted to be turned in opposite directions by successive extension strokes of the piston, connecting means operatively connecting the cam means to the switch points to move the switch points between either limit position upon a predetermined amount of rotation of the cam means in one direction or the other, control means for the motor and hydraulic control valve including detecting means to detect arrival of the switch points at the second position during a throw and effective thereupon to reverse the hydraulic control valve to cause retraction of the piston thereby conditioning the piston for the next extension stroke thereof which will reverse the switch points from the second to the initial limit position, said control means then reversing the hydraulic control valve again to recondition it for a subsequent extension of the piston immediately upon the restarting of the hydraulic pump.