Factorio Forums

I've played around with trains a fair bit now and I just want to confirm one last thing with rail signals.

If there are two possible paths for a train to take to get to a particular stop, the train seems to bias one or the other. If the path it always selects has a red light block, the train will not seek an alternate green light block. Is that right?

Example:
Train starts in block 0 which has outgoing connection to block 1. Block 1 has a fork to outgoing blocks 2 & 3 which merge outgoing to block 4. The train seems to bias block 2 for some reason (path finding algorithm I guess). But if block 2 is red before the train in question leaves block 0, the train will wait in block 1 instead of going through block 3.

If that's true, has anybody got any tips for better managing that situation?

That should not happen as you described. Try removing the biased route by breaking a section of rail to see if it will take the alt route. I suspect there is something else stopping it.

Thanks Starxplor, you're right. I don't have the original set up that made me come to that conclusion but after reading your post I set up an isolated test and was able to get the train to seek the alternate root. Woo!

As a side note, I think I found a bug in the signal placement when setting up the test case. Check out the left most green signal in the first image below. It looks like it's on the right hand side of the track but it's actually for traffic going the other way. The signal snaps to 4 locations as you move across that join. I think the inner two are meant to be blocked or hidden.

The bottom image shows that signal in the correct location.

Hm. This looks like a bug to me. Would be nice someone can make a link from the bug section to this?

I created a topic in bug report section linking here