Factorio Forums

From the thread here regarding strange collisions on properly signalled tracks, this is more or less a copy of my post there.

It seems to be caused by the global repath/disruption that triggers when building rails. To make it somewhat reliable we're using the "blueprint of death" to build lots of rails and kill UPS.

To use reproduction save:
Change the requester chests containing rails (marked with orange in the setup picture) to storage, this starts the construction.
Once UPS plummets turn off the constant combinator (purple) to launch the trains.
Enjoy the slow motion crash.

It's not 100% reliable and results may differ a bit from run to run, but it's clearly not working as it should.

i confirm

Thanks for the reports,

Does this issue persist in 0.15?

I'm not 100% sure. The reproduction case I attached earlier does not seem to work any more so things have improved. That said I have had instances with trains running through signals into other trains when building/deconstructing large railway intersections or things like that. Mainly instances where I've been off working on an intersection and then notice that my throughput tester has stopped only to find it full of broken trains.

I'll have to look in to making a new vanilla reproduction as the problems I've observed are in a save with creative mode which may have caused some interference (even if I've used construction robots to build/deconstruct). For now though I guess this belongs in pending.

Klonan wrote:Thanks for the reports,

Does this issue persist in 0.15?

It seems to, yes.

http://imgur.com/a/HY6S7

I had a collision in a properly signaled block where both trains were in automatic mode. I am not certain I was building rail at the time because I didn't see the collision but I likely was. I was placing a large amount of rail between the time there was no collision and there was a collision.

Elan wrote:I am not certain I was building rail at the time because I didn't see the collision but I likely was. I was placing a large amount of rail between the time there was no collision and there was a collision.

it might be fixed for you then: viewtopic.php?f=213&t=51829

I am not sure is this same or different bug what I have get with 0.15.x versions. I have quite big mega base and randomly some of my trains crash on signals. They can run nicely several days or even week without problem and then crash boom. I havent see how it happen because usual when I notice it there is just hole middle of train and another damaged train some where else. Anyway last time I manage to capture screenshot. I understand that this is so random that it can be nearly impossible to reproduce that and because that it can be hard to fix it. Anyway just for information that there is still some kind bug with signals with 0.15.33

Here is another example of what is probably this bug in 0.15.37. In the thread a lightly modded (nothing that should affect trains AFAIK) savefile is included unfortunately it is after a collision so I'm not really sure how helpful it is.

While I still can't make a good reproduction I thought I'd at least link this as it may give some clues.

I think that this bug was likely fixed in 0.15 as Klonan suggested, the crash I linked to earlier was likely one of the issues that was fixed in 0.16. As I have not been able to successfully replicate this bug since 0.15 it seems fair to to me to call this one resolved.