As I plan the electrical system for my new N road, I want to repeat a feature I've had in all of my previous layouts -- a master ON/OFF switch to assure that everything is cut from household power. A nearly 40 year old obsolete Radio Shack toggle switch is shown below that I used long ago. I like it because the toggle action is Rolls Royce smooth and tip glows amber when the power is on. It has three connections and I've long since forgotten how I had it wired. Can someone help? I'd rather not hook it to house current to experiment. When I hook an ohmmeter to the bottom connections, it switches on and off, but the top connection has me baffled. Do you think that it's what powers the lamp in the tip? The top connection has no continuity with either of the bottom two regardless of switch position. Thanks for any advice.