556 Timer Stall-Motor Switch Machine Drivers

The circuits on this page are switch machine drivers that can be used to operate Stall-Motor type switch machine motors. The circuits use LM556 dual timer chips to provide a PUSH-PULL output to reverse the polarity of the supply to the switch machine motors.

The 556 timers provide a logic function equivalent to a SET / RESET type Flip-Flop. This gives the circuit a memory function that allows the turnout to remain in its last position when the input push button switches are open.

The switch machine used to develop these circuits is the Circuitron Tortoise™ slow motion type switch machine (Model number 800-6000). Other makes of stall motor switch machine should also work with this type of circuit.