Ed, I installed Atlas O Signals on my layout. I used a couple isolated rails on short single track sections through switch areas. Both signals will need to be hooked to the combined hop-scotched single track sections.
When one of the tracks is bridged, the signals will turn red. The automatic timing in the signal will then turn yellow to green on both signals, once the engine or cars are out of the area. Movement along the pathway of any single track isolated rails keeps the signal red, until the track section(s) are vacated. Each signal should have its own board wired to the pattern of isolated rails. (Two or three single isolated rail tracks will trigger the signal to red. You don't need a long stretch of track because the length of the train will continue bridging the connection for the signals.) A slow moving single engine might have difficulty making it from one isolated rail to the next. A train should not have this difficulty.
The hop-scotch pattern of isolated rails allows you to power both outside rails on non isolated track sections. This will help Legacy Remote Signals reach your engines better, especially with Atlas O track.
The downside of this is that the remote daisy chaining of signals will not work with this section of track. The daisy chain is good on a circle of track in one direction to speed up the changing of the red to yellow to green. (This is for large layouts.)
Sincerely, John Rowlen