Factorio Forums

Is anyone suddenly having trains crashing at junctions? I have trains being split into 2 parts and cannot find the issue

Are your trains very long? A train can collide with itself if it repaths in a roundabout.

Yes .... The trains that are crashing have 2 engines,4 coaches,2 engines,4coaches,2 engines and my whole train network is setup to work via roundabouts. I have never had issues in the past. I use Rain Chain Signals to control the entrances to the roundabouts and the same in between sections in the roundabout.

Is this a change in the way trains work just introduced and what are the rules about length of trains. I have much longer trains running than this and they do not have an issue

If you avoid doing anything that causes a repath, you won't have issues. Or don't do them when trains are in a roundabout.

The most common causes of repath are:

• Removing rails
• Disabling stations with circuit network

Thanks. My roundabouts are all double tracks with 4 in/out. I tried a few weeks back to force trains around a section in a one way direction. I just removed track sections. It must have been that. Have put them back and it seems better. Will run the program for a week 24/7 to get all the trains to move and destroy the one that repath and then pick up the pieces.. I have a very large base now - does not fit one screen anymore.

In general - if you use roundabouts make sure that no train is longer than your roundabout size. Many people warn from using them, although I had never real issues with them. Although I did follow that important rule with the train length limitation. Even if under normal circumstance trains don't reroute, it might happen under circumstances you didn't forsee sooner or later. And in these cases you really don't want them to crash and block your whole train network.