To be clear, your 20 foot run is a single "block" of track. The center-rail and outer-rails are continuous from end-to-end. There are no cuts or breaks or "isolated" sections. The timer module has a relay which has ON-OFF control to the entire 20 foot track. All or nothing!
“No breaks or isolated sections” ?
I was planning on insulated sections to activate road crossing signals. Is that a problem?
Unrelated to that, can this “accessory” be used to turn station lights or parking lot lights (or a “Welcome to Twin Peaks”) Sign on and off ? A little more action to surprise the grandkids! This is complicated enough for me so if the answer is “yes but” then I probably am not interested.