Thanks all. Yes, it's the Lionel plug, expand, play bridge, Lionel #6-83174. I'm also using Lionel #6-81317, the accessory activator track.
Unsurprisingly, I've put this double signal bridge over two loops of track. It works correctly on one, not on the other.
The inner loop works fine. I used the accessory activator track and removed the metal strips from underneath four Fastrack curves (O-36). The four curves and the activator track itself are between the two 5" insulated sections. The signal works perfectly. It's green until the train enters the loop, then it's red while the train is in the loop.
On the outside loop, I went even simpler but it's stuck on red all the time. I removed the metal strips from two curves, which are the only pieces between the two 5" insulated sections. I remembered to put the breaks in the insulated sections on the same rail, both on the same side of the track as the plug. (This is also what I did on the inside loop, which works fine.) And yet the signal remains stuck on red all the time. Is this just defective or is there some common error I haven't tried correcting for yet?
Thanks!
