Where does the wire from the frog attach to the Walthers machines?
In their installation video, it looks like the terminals on the micro switch are labeled NC, NO and C. You want the C, for common.
I assume NC is normally closed and you would put the polarity at that electrode that you need at the frog when the switch is in the straight route posiiton. A $4 harbor freight voltmeter would verify that.
Henry
COB Potomac & Northern
Shenandoah Valley