Train reporting self intersection won't use roundabout

Issue description

The train is stuck before entering a roundabout to turn around. The roundabout is entirely one way track. I've tried with default track settings, and now with setting exclusive and no stop zones across the entire roundabout (this is how the attached save is). The roundabout is clearly bigger than the train and there would be no intersection with itself.

I have no idea how to diagnose the issue with the train, the 'view pathing' button just shows the train as some red boxes, the path as orange. I did notice that another train has a green path and yellow boxes ahead of the train, but there are no tooltips, the tools don't help me diagnose it at all.

No salt intended, I love you guys and this game is incredible <3

Reproduction steps

1. load attached save
2. inspect the train with the warning on it 'self intersection' and the route it's meant to take

Game version and build number

v0.7.4 b441

Operating system

Windows

Attachments

Save 2025-06-05, 20-13-15.save

You can resolve this in your case by removing the "no stop" condition throughout the round about.

The reason this happens is that when a train is traveling along a track, it "projects" a path ahead of it and checks the conditions of that path to see if it can go forward. If part of this projected path is "no stop", then it will extend the projection until the end of the no stop section and far enough beyond so that the train can safely stop, if needed, on the other end of the no stop section. But in your case, the train will project the path all the way around the round about and find a train already there (the same train), thus it cannot proceed.

As long as you are using bidirectional rails like this, the no stop will have to be excluded from roundabouts to function. Once you have two, single direction tracks, you can include no stops to keep the roundabouts clear, if desired. In this case it has no positive effects anyway.

I see. That explains why the other roundabouts didn't see the issue,
because the train could fully fit on the roundabout.

When toggling on the train routing display, the orange line was indicating
a problem.

So this is not a bug, but a usability feature request for better
indications. Perhaps if that orange line had a tooltip explaining why it
was orange, e.g. "cannot find sufficient stop zone ahead - Train#3
encountered"

On Sun, 8 Jun 2025, 18:01 Fujite, @.***> wrote:

Fujite left a comment (MaFi-Games/Captain-of-Industry-issues#1980)
Train reporting self intersection won't use roundabout

You can resolve this in your case by removing the "no stop" condition
throughout the round about.

The reason this happens is that when a train is traveling along a track,
it "projects" a path ahead of it and checks the conditions of that path to
see if it can go forward. If part of this projected path is "no stop", then
it will extend the projected until the end of the no stop section and far
enough beyond so that the train can safely stop, if needed, on the other
end of the no stop section. But in your case, the train will project the
path all the way around the round about and find a train already there (the
same train), thus it cannot proceed.

As long as you are using bidirectional rails like this, the no stop will
have to be excluded from roundabouts to function. Once you have two, single
direction tracks, you can include no stops to keep the roundabouts clear,
if desired. In this case it has no positive effects anyway.

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A train checks its path through the whole no-stop section ahead, so on a roundabout that is all no-stop it finds itself in the way; removing the no-stop zone from the roundabout fixes it, as found in this thread. If you would like it to work differently, please post it as a suggestion: https://coigame.com/Forum/Suggestions