I agree that since it is a "red over" you might "assume" that it is for a diverging route.

But I was told years ago, it is a "know nothing" signal. A flashing red or lunar usually allows you to proceed at restricted speed, but who knows where to or what is in front of you. Restricted speed can get you in a whole lot of trouble if you aren't careful.

Then again, you have to look at the timetable and special instructions for that location to be sure the railroad didn't decide to have it specify something different.

Several years ago I read where genius railroad insultant recommended that there be several more restrictive aspects. I believe he wanted purple as another color.

Are we having fun yet?