OK, understood we're talking about an add-on.
So is there a visual indicator of which siding has power? Lighted bumper, control panel LED, etc?
I'm still curious about having to first return to the "OFF" position when changing active track. The club guys will learn by experience but I'm thinking about your visitor day scenario. The approach in the other thread uses a relay-per-track which is not a drop-in mod for your configuration. But what about "automating" just that single relay that toggles power to the passive-mode TIU output? In other words whenever and while the rotary changes position, it disables the relay and then re-enables it after the rotary has settled on the new position. I'm not saying it's a simple circuit but more in the spirit of a discussion about dealing with what appears to be more than a one-off.
