Pre signals are green when all exits are red - OpenTTD

Question

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?

Thanks!

Answer 1

The signals in front of the station needs to be exit pre-signals.

You're currently using normal block signals, which means that the entry pre-signals should find no valid exit pre-signals, and will act like normal block signals, and thus be green since no train is occupying the next section of track. The trains should not recognise the tunnels as valid exits, since, as you mentioned, they are one-way signals.

You can find out more about pre-signals by reading the wiki: http://wiki.openttd.org/Path_signal#Pre-signals