I’ve just picked up a K Line O27 uncoupler Track, one of those odd items that appears on eBay and nobody wants it.
Looking at the wiring, it looks very simple compared to a Lionel unit - a single wire to a single button. The printed wiring diagram on the packaging shows the wire going to one side of the transformer.
I’m intending to fit this unit to my O27 door layout. Am I right in thinking that the wire could be connected to the earth side of the nearest lock-on?