[0.11.8][kovarex] Train stops with "no path" error

[El-Lobo]

In my current train-heavy playthrough sometimes (approx. once an hour) a train stops at no specific place with the "no path" error. This can of course cause massive jams.
Pausing and unpausing the train fixes it every time. No other manual intervention is required.

Interestingly the rail blocks directly south of the train have all yellow signs.
My idea would be that the train planned to go south but didn't? => trainpathing "crashed"? That would also explain why i also had two traincrashes, what shouldn't be possible with the logic behind blocks.

Savegame and used mods:
https://www.dropbox.com/sh/t3embnr4wcwe ... u041a?dl=0

*Edit: the yellow signs disappear the instance i hit the pause train button.
**edit: added version to title

[JLBShecky]

If I had to make a guess I would say that it is one of two things.

A) It is possible that you may be using the faster locomotives, I remember having issues with them going so fast that block themselves via the path finder.

B) What I think it may have happened in this case is that the train go caught pathing around itself on the loop. That is to say that the stuck train tried to go south, but saw the iron train had reserved that block, so the train repathed to go around the circle. If the stuck strain had to much speed as it tried to go around the loop it could have thought it would crash into itself or discovered that the other block was still being occupied by the iron train and messed up with pathing logic.

All that being said that is some complicated siginaling that you have there, but I do think that there might still be something in the train's path scheduler that is messing up. I would say that it might be reaching a race condition, but that is a little to close to a pun...

[El-Lobo]

It's not A. I'm not using any other trains than the normal ones.
An i don't think it's B either. The iron train is stopped as well. Also the red signal in front of the iron train wouldn't be there, if the following block is reserved for this train.

[sillyfly]

What version of the game are you using?
I think there was a bug a while back that in some cases a train would take the wrong turn (i.e. - wanting to turn left but actually turning right). This seems a lot like what happened here. Sadly, I can't seem to find the thread I am thinking of (maybe I'm imagining it?)

But specifying what version you are using is always a good step :_

[El-Lobo]

Argh, i knew, i forgot something.... Running on version 11.8.

[El-Lobo]

And another weird one. The upper two lanes to the left of the image are completely congested by at least 10 trains. Circled signal lights make no sense. The next stop of the bugged out train would be straight to the east. So it is on the right track...

[kovarex]

Thank you for the report, I don't need any more info, I know what the problem is and I can reproduce it easily now (when I change locomotives to be super high speed).

I'm working on a solution.

[roy7]

Thank you for the report, I don't need any more info, I know what the problem is and I can reproduce it easily now (when I change locomotives to be super high speed).

I'm working on a solution.

MagLev trains, here we come!

[El-Lobo]

Great. Thanks and happy to help!

[kovarex]

Fixed for 0.11.11

This was quite radical fix (changing some deep logic of trains).

I will write some automated tests and test it on your map to see if I broke something or not tomorrow, once I finish other train problems when I'm on it.

But in my test of super fast train with lot of junctions that could be missed, it failed miserable before, and now it works fine.

[kovarex]

As I did some other fixes and internal train logic reworks to make the trains more properly. I used your map as testing enviroment and I have to say.

1) Wow .. just wow the map is so impressively huge and the setups are really nice, I was just picking up random trains and riding them around for pleasure
2) The map had (after the chart was refereshed after the transition to 0.10.10) 12/32 (Fps/Ups), which is not so nice, I did some quick profiling to see what is the reason of the map being slow in your case (I was really expecting trains). but I found out that trains is eating only 3% of the update time, most of the time is taken by other common things like transport belts/belts to ground inserters and such. After the last time I'm quite sure I will hold myself from doing optimisations now, because I really need to stabilise the 0.11 first. But 0.11 is done, and I start working on 0.12, I will definitely work on the optimisations of the game until I get clean 60/60 on your save, as it just deserves it

[El-Lobo]

I'm sooo looking forward for the next update. In my new game everything is handled by trains. Every production facility is separated and no belts are allowed between them. Even those annoying copper cables have to be transported by train. If there is a bug in the new train logic, I'll find it!

[n9103]

Congrats on being the official test-case for breaking trains

[Wessel]

Good to hear you have found a fix already.
Just to be complete, I ran into the same problem on a super simple track layout:



Train will not path to the westbound station. But after I manually drive across the red line, it will.
Even after removing the top portion of the loop, it will still not path.

(Or it could be I am doing something terribly wrong, of course )

Factorio 0.11.10, btw

EDIT: Never mind, screwed up the signal placement

[kovarex]

Do you realize you are using one way signals in opposite directions?