Intermittent signal fault

[hlg]

Has anyone met this situation before ?


See the attached screen shot. My trains etc are in light blue. While I was laying the tracks from the station at the bottom left of the screen ("Cataito North", though this isn't clear), the AI put station "Machala South" in the way, so I tunnelled underneath it.

Signal 1, near the centre of the screen, is normal. Signal 2, at the bottom left is a pre-signal.

Every twenty trains or thereabouts, Signal 1 refuses to turn green once a train had left its block and gone into or through the Cataito North. This leads to trains queueing behind Signal 1, and the system eventually getting jammed.

I have tried removing Signal 2 and making Signal 1 the pre-signal. This seemed to reduce the frequency of this failure, but didn't fix it entirely. I did notice that the all trains affected were proceeding under "non-stop" instructions to stations beyond Cataito North, but this may not be significant since there were eight of these compared with only two which stopped at Cataito North. I deleted and rebuilt the trains, but this made no difference.

I also tried correlating the failure with the movements of trains into and out of the AI-controlled station "Machala North", but the signal failure always happened while I was looking somewhere else on the map.

My next step is either to demolish my layout and rebuild elsewhere (tedious) or buy out the AI company which owns Machala South (expensive).

Any ideas, anyone ?

[Patchman]

The depot is the problem. Due to a bug in TTD, depots "connect" to the track behind them. Also, tunnels "connect" to the track above them.

Normally, you'd just remove the depot and put it elsewhere, not above the tunnel. But since it's not your depot, you have to make your tunnel one square longer.

[Prof. Frink]

It's the depot.

TTD sees the depot as a type of track and the tunnelentrance as a type of track.

As they're in adjacent squares, end-on, it sees them as connected.
Any train on the upper line will cause that signal to go red.

Make the tunnels one square longer and it'll work.

[hlg]

Thanks for the speedy response, guys !

As I said, I had a vague idea that the AI train movements were affecting my signals, but hadn't twigged how this was happening. (Slaps forehead.)