Factorio Forums

Ok I'm sure I'm just being stupid but I just can't work out what to do.

I want to make my two train routes share the middle piece of track. Both trains have engines at both ends so they go in both directions along the track.
Thanks

So what you need to do is have a chain signal before the shared section of track, and a regular signal after the shared section of track.

This way a train will only use the shared section if it's able to go past it, so it won't block the shared section and lead to a deadlock.

You'll need to do this on both sides, of course. So from each direction, you have a chain signal, then the shared section, then a regular signal after the train exits the shared section.

Kyralessa wrote: Mon Dec 12, 2022 5:03 pm So what you need to do is have a chain signal before the shared section of track, and a regular signal after the shared section of track.

This way a train will only use the shared section if it's able to go past it, so it won't block the shared section and lead to a deadlock.

You'll need to do this on both sides, of course. So from each direction, you have a chain signal, then the shared section, then a regular signal after the train exits the shared section.

Thanks so much for this!
I'm sorry I think I did what you said but it didn't work, I don't think I understand where exactly they need to go in relation to the sections of track. Would you mind marking for me on the screenshot where a Regular (R) and where a Chain (C) need to go? I think that would help me undrstand

Note that if it gives you trouble placing the signals, try placing a pair of signals in the middle of the shared section, one on each side of the track exactly across from each other (as a way of telling the game that the track segment is a two-way track). Once the other signals are placed, you should be able to delete the extra signals in the middle. (Although, also note, that if this is the case, then that's an indicator of bad/lack of signaling in the rest of your track segments.)

FuryoftheStars wrote: Mon Dec 12, 2022 8:07 pm Note that if it gives you trouble placing the signals, try placing a pair of signals in the middle of the shared section, one on each side of the track exactly across from each other (as a way of telling the game that the track segment is a two-way track). Once the other signals are placed, you should be able to delete the extra signals in the middle. (Although, also note, that if this is the case, then that's an indicator of bad/lack of signaling in the rest of your track segments.)

Thanks a lot for this.

It still doesn't work, both trains are saying 'no path'

The rest of the tracks just run completely independantly so I don't have any more signals any where else, am I meant to?

Attached is what I think is the same as the image you posted

BioMannequin wrote: Mon Dec 12, 2022 9:51 pm It still doesn't work, both trains are saying 'no path'

The rest of the tracks just run completely independantly so I don't have any more signals any where else, am I meant to?

Attached is what I think is the same as the image you posted

I think you have the chain and standard signals the wrong way round at the right-hand end.

Khagan wrote: Mon Dec 12, 2022 10:29 pm

BioMannequin wrote: Mon Dec 12, 2022 9:51 pm It still doesn't work, both trains are saying 'no path'

The rest of the tracks just run completely independantly so I don't have any more signals any where else, am I meant to?

Attached is what I think is the same as the image you posted

I think you have the chain and standard signals the wrong way round at the right-hand end.

This ^^

Here's a higher res image with letters added

BioMannequin wrote: Mon Dec 12, 2022 9:51 pm It still doesn't work, both trains are saying 'no path'

The rest of the tracks just run completely independantly so I don't have any more signals any where else, am I meant to?

The signaling shown by FuryoftheStars is for train driving on the left side, this may explain (reason1) why trains are showing no path on your game.

Each signal, similar to train station, are placed on the right side of the track. They give an orientation to the track. (the white arrows on next picture). If you take Fury's last picture with letter but with the train stop on the other branch on both side, it would show "no path" due to the signal giving the track a different orientation than the station located a little further down, making it not possible to reach.

If you were to signal for train driving on the right side of the road instead of left. Then signals would no longer appear as touching each other, but instead be separated by a piece of track. (notice how the arrow always has the signal on the "right" side if you think you are a train following it.)
Both ways shown on this picture have the same behavior in game, the one on the bottom makes it more visible that the middle piece of track is a 2 way track with signals on both sides.

You may then realize another problem which could lead to train saying "no path", that is if the trains shown on the picture are tasked to reach the other station. (reason2)

This is because although the middle piece is a 2 way track, each of the 4 branching is either an entrance or an exit for that middle block based on which side the signal is located relative to the track of that branching. They are not both at the same time, for this each branch would require a signal on each side of the track, like this :
Both ways shown here are the same behavior in game allowing trains to go back and forth between stations.

Depending on the rest of your network, and what you had in mind for this particular area maybe the signaling should be done according to :

Fury's last picture (train drive on the left and not asked to reverse)
picture 1 from this post (train drive on the right and not asked to reverse )
picture 2 from this post ( train are asked to reverse and therefore drive on the left or the right accordingly)

I hope i didn't make it more complicated

BioMannequin wrote: Mon Dec 12, 2022 9:51 pm It still doesn't work, both trains are saying 'no path'

In Factorio you can use right-hand drive or left-hand drive for your trains, whenever you have more than one track.

However, you must always put the signals on the right-hand side relative to the train's direction. In right-hand drive, that means in a pair of parallel tracks, the signals will be on the outside. In left-hand drive, the signals will be on the inside. The signals must always be on the train's right-hand side as it approaches them.

In your image, the signals on the left end are fine, but the signals on the right end are on the wrong side of the tracks. Or, to look at it another way, the signals on the right end are backwards; the chain signal should be where the regular signal is, and vice versa.

It works!! Thanks so much everybody for taking the time to explain and help!

mmmPI wrote: Tue Dec 13, 2022 7:35 am The signaling shown by FuryoftheStars is for train driving on the left side

Yup, I did that because I got too hung up on the concept that there were two separate rail routes and looking at that train in the original image, it was on the left track driving east, thus in my mind seemed like an LHT setup. Except I'm realizing now the double-headed train concept, meaning all rails are two way, it's just that one section is shared.

As such:

mmmPI wrote: Tue Dec 13, 2022 7:35 am picture 2 from this post ( train are asked to reverse and therefore drive on the left or the right accordingly)

I believe may be the correct answer, especially with the inclusion of that second image from the OP that actually shows the station inserters and pumps.