[0.12.22] [Dominik] Train block its own path with chain signals

[Blue_Lucario]

This is a miner annoyance more then a bug.

The train can't get to the station because there is a train on the tracks.

preview.png (414.67 KiB) Viewed 38636 times

This should never happen on its own but I found one like this on a loop in my world.

[DaveMcW]

Bad roundabout design, you need a normal signal on the exit.

[Blue_Lucario]

Dear DaveMcW,
My design is something more like this.
The four chain signals are so trains can go straight or turn right without blocking the whole roundabout.

preview.png (467.76 KiB) Viewed 38593 times

[DaveMcW]

Ok, so it does get stuck if the train goes down the wrong path.

The question is, how did the train go down the wrong path in the first place?

[Cbrad24]

He said himself it can't happen on its own. This is only possible if your train is manually stopped or runs out of fuel in the middle of your intersection, AND is told to basically do a U-Turn (in this instance go South). Because of the trains length its occupying 2 blocks, which is blocking itself.

The devs can't do anything to solve this as everything is working as it should (unless you give temporary powers to ignore signalling). Making trains ignore signals turned red by themselves would result in cases where trains will collide with their tail end. If you still get annoyed by this then to solve it you will have to either make the roundabout larger to accommodate for the length of your trains, or shorten your trains length.
Also a temporary fix as opposed to getting in the train is change the signal in front of it to a normal one for a second.

I scribbled over your image to help you understand why its gone wrong.

preview.png (573.99 KiB) Viewed 38526 times

[ssilk]

It could be solved if the game would do a simulation in that case: What would happen, if the signals where green instead and I move anyways? Will I hit myself or not?

I guess: This is too complex for this low number of cases...

[Cbrad24]

IMHO nothing needs to be done. Automated trains will NEVER do a 450 degree loop (1.25 rotations), so even the longest Factorio train in the world won't get stuck. It can't get stuck any other way than manually forcing it to jam up.
Unless I'm missing something here OP?

[Blue_Lucario]

I have been testing an 8 lain 4 way intersection for fun and this post.
4 rings inside each other and 16 intersecting strait lanes add about 20-30 trains running around like crazy...
...and you get this. Twice.
It did it by its self.
And yes I did windup making the center loop bigger and it stopped happening.

Not a very big problem. I just thought I would like to bring it to the attention of the bug list.
I am trying to report more stuff for the steam addition.

[ssilk]

IMHO nothing needs to be done. Automated trains will NEVER do a 450 degree loop (1.25 rotations), so even the longest Factorio train in the world won't get stuck. It can't get stuck any other way than manually forcing it to jam up.
Unless I'm missing something here OP?

You don't need to make 450 degrees. I've a setup, where I have such a circle, that the train comes in from the left side, makes a 270 degrees loop and goes out into down direction. Nearly equivalent to this setup, but with the distinction, that it is not possible to go down, when you come from left (the reason, why it makes a 270 degrees loop).

This deadlocks, if the train needs to wait inside the loop (cause a train comes from up for example), but works nice in all other cases. After resolving the deadlock I need to restart the train by hand.

But I admit: This is really a rare case.

[mophydeen]

round.png (3.01 MiB) Viewed 38415 times

[Cbrad24]

You don't need to make 450 degrees. I've a setup, where I have such a circle, that the train comes in from the left side, makes a 270 degrees loop and goes out into down direction. Nearly equivalent to this setup, but with the distinction, that it is not possible to go down, when you come from left (the reason, why it makes a 270 degrees loop).

This deadlocks, if the train needs to wait inside the loop (cause a train comes from up for example), but works nice in all other cases. After resolving the deadlock I need to restart the train by hand.

But I admit: This is really a rare case.

I'm trying real hard but I just can't see how the train would ever have to wait in the intersection? From my point of view this whole thread is just an issue of signal design being prone to overlooked scenarios, but you're all making me feel like I've missed some big secret

The only thing I can envision to replicate ^that is one of your entrances isn't chain signaled? Someone help me replicate this

[MasterBuilder]

I have a design that has caused this to happen. It's very rare, like only two-three occurrences in this game.
Thing is it doesn't always dead-lock. I can cause the train to do a loop but never made it lock on command from said loop.

Here's a pic of the train's expected path being a loop: (And it doesn't deal-lock while making the loop either.) (Using 0.12.21)

Trainlock.png (4.11 MiB) Viewed 29759 times

I can even cause this to happen but that's not enough for a dead-lock.

Trainlock2.png (4.23 MiB) Viewed 29752 times

[orzelek]

Do check if dead lcok persists through save/load cycle.

If it does save would be very useful for diagnosis.

[Blue_Lucario]

Hay MasterBuilder, what mods are you using? Your trains look amazing!

[MasterBuilder]

Hay MasterBuilder, what mods are you using? Your trains look amazing!

Yuoki Industries Railways

[HanziQ]

I'm not sure if I consider this a bug, if I allow this, it would be possible for a long train to hit itself.

[Rseding91]

I'm not sure if I consider this a bug, if I allow this, it would be possible for a long train to hit itself.

I'm in favor of this

[Kevin94]

I've found another type of that problem:

ChainSignalDetail.png (606.77 KiB) Viewed 28558 times

ChainSignalMap.png (8.93 KiB) Viewed 28558 times

The Signals in the track-triangle are all chain signals. The train should take the roundabout and leave where it has come from.

It's no issue that has to be solved, as it is no problem at all to add normal signals or a parallel track to solve this. My whole Train Network in this world is just a WIP. Just wanted to mention it.

[HanziQ]

Ok, I will change the behavior, but I'm postponing this till 0.13

[jarcionek]

I've found another type of that problem:

ChainSignalDetail.png

ChainSignalMap.png

The Signals in the track-triangle are all chain signals. The train should take the roundabout and leave where it has come from.

It's no issue that has to be solved, as it is no problem at all to add normal signals or a parallel track to solve this. My whole Train Network in this world is just a WIP. Just wanted to mention it.

Kevin, this is bad design of your rail network. The roundabout should be separated with the signal (more precisely a pair of them so the trains can go both ways). Because you have chain signal it will still not allow any train to go to the roundabout, even if another train is there.