I have two parallel tunnels (one-way) that lead to a station with 3 platforms, since this line is very highly trafficked. When the trains emerge from the tunnel, I would like them to stop and wait (before crossing the track intersections) if there are no available platforms.
I figured this was a simple task using normal signals (for each platform) and pre-signals (for each tunnel exit). However, the pre-signals remain green when there aren't any platforms available!
Here's a capture of such a circumstance. You'll notice the pre-signals at the two right most tunnels (ignore the left two tunnels and their track, they're irrelevant) are green, despite all platform signals being red.
I think it might be because the two tunnels are connected by a 90-degree turn, which the game recognises as a possible route. Despite the trains being unable to go back through those tunnels (the pre-signals are one way), the pre-signals are recognising each other as potential exits and so remaining green, but that's just my (probably incorrect) diagnosis.
Am I misunderstanding how these signals work?
What is a working configuration for this setup?