What is the purpose of the O22 turnout’s middle post and under what conditions would it need to be wired?
When I have asked about wiring O22 turnouts in the past, several people have responded and shared that the middle post (common/ground/outside rail) does not need to be wired, but I never asked why.
The layout wiring is moving along, and the turnouts are next. I want to make sure I am not overlooking something by not running three wires from the turnouts to the control board.
By the way, somone recommended using buss bars under the table for wiring. Excellent suggestion! I find that buss bars are much easier to use for star/home run wiring than terminal /barrier strips. The buss bar screws clamp down nice and tight on 14 gauge wire. A 21 position bar costs about $4.50. One for outside rail, one for middle rail, and one for constant voltage on turnouts. Can’t beat the price, ease, and durability.
You don’t need to connect anything to the terminal (not a “wire nut”) on the turnout, but you do need to connect the controller wire to the equivalent point, for example, the outside rails directly or the common terminal of the transformer.
So it sounds like the only purpose is to make working with the included SPDT lever easy. That way one doesn’t have to understand, or worry, about hooking to the outside rail. Just hook the included lever to the three terminals and you are done.
I only use the two terminals. I buy “zip” cord or lamp cord for this use, its cheap and readily available. Then of course the control panel needs a nice large return (common) to the transformer(s). I dont use the lionel lever switches, rather opting for illuminated pushbuttons embedded in the track diagram at the control panel.
Or, you can bolster your common ground by dropping a wire down from the center terminal to your ground buss.
Or, go one step further & additionally use a coaxial plug in place of the fixed voltage plug on the 022.
Connect the center(tip) to fixed voltage for switch operation, and the barrel(ring) to track voltage.
Now your 022 is acting in the capacity of a lockon w/o being obvious(five wires to each switch - straight & turn(from controller), ground, fixed AC, & track AC(from busses)). I’ve done this for 25+ years, some people are amazed when they realize I’ve built the whole carpet central layout w/o any lockons.
Another alternative to both the Lionel controllers and other momentary switches (pushbuttons or toggle switches) is a simple metal stud (like a screw head) in the track diagram. You use a single probe wired to common to touch the stud in the track that you want the turnout thrown toward.