Trouble with Basic Signal Setups

I'm really having a hard time getting a basic signalling setup operational. Without going into a bunch of detail, I thought I'd post an example that is confusing me. The attached screenshot shows the Midwestern Branch during session edit. Can someone tell me why the signal is showing yellow and not red?

Even more mystifying is if I move the oncoming loco closer to the signal, it turns green.

That's unusual for the signals to react this way, but I assume that Surveyor mode is paused here since you are using Platinum. Un-pause Surveyor while editing and I'm sure the signals will react the way they should.

That's because it's RRSignal's TRI Switch Indicator Signal RRS Supersignal. According to the description:
YG. A single-head switch indicator on a 17-foot post. It displays green for switch closed, yellow for switch open. Switch direction is set in the Property Editor menu.

Ah. That's interesting. I never would have thought that. Thanks for the info!