Train Network Help "No Path"

[tbahr4]

Hi! I'm new to this train network stuff and I need some help with using two trains on one track. I understand that train stops need to be on the right, but I can't understand the concept of signals. So, I get the "no path" error.





So, whenever the train starts moving to A2/B2, I want it to go to the top-half of the of the tracks. When it returns, I want it to return through the bottom of the track without interfering with the other train.
Thanks for the help!

[timothy_johnson]

The chain signal and the regular rail signal look at the tracks ahead differently. The regular signal just checks to see if there is a train before the next signal, whether that next signal be a chain or regular signal. The chain signal checks to see if there is a train before the next signal OR if the next signal is red. In either case, the chain signal will be red. If the chain signal checks ahead and there are multiple paths, then it will be green if they are all open, blue if at least one is closed, and red if they are all closed. Generally, you want chain signals in and before intersections and regular signals everywhere else.

As for your design, if you put a chain signal before any junction and a regular signal immediately after any junction, it should fix the problem.

EDIT: Also, I assume you have engines on the trains facing both directions. Trains don't automatically reverse in Factorio.

[twepy]

To start with the basics. Signals have two functions, keeping trains from colliding and a less obvious function it dictates the drive direction on a block.

RailwayBasics.png (213.61 KiB) Viewed 20262 times

Based on your schema its has only one way track with opposing signaling so trains never can reach their destination. The solution is simple, add signals to make it two way and for the passing track you make it either one way of two way. In the example below both a one and two way passing track is shown. The yellow marked signals are chain signals and the green are regular signals. The train stops are only there to make the trains run, their arent necessary for a passing track.

passing1.png (649.27 KiB) Viewed 20262 times

[hitzu]

Double signals are redundant.

[zebediah49]

If your drawing is correct, your signals are on the wrong side.

If your train is going "up", the signals for it need to be on the right side, as does the station. As posted further up, if you want to go back down the same track, you will need a signal on the left as well.

Note: an [automatic] train will never cross a signal to its left, unless there is one paired on its right.


E: Also, trains only go automatically forwards. If you only have "forwards" engines, it can't go backwards.

[siggboy]

You appear to have two tracks. That's good. Always run two tracks in parallel, one for each driving direction.

Put the signals to the right of the track, when facing the driving direction. That means if your trains drive "on the right", the signals will be outside of the pair of tracks. If your trains drive "on the left" the signals will be on the inside.

If you want to join both tracks then you'll end up with a single track that needs to allow both driving directions. In that case you always place the rail signals in pairs, directly across eachother by the track (the game displays a little white marker alongside the green markers when it detects a possible position for such a signal pair).

Generally it's much easier to avoid "no path" problems and deadlock problems if you always have two tracks (one for each driving direction), and don't require the trains to share a single track.