Factorio Forums

whats wrong is it a bug or a bad setup.

You want a chain signal somewhere on the track that your stuck train's cars are mostly on.

When a train picks a station to go to, it paths to it and doesn't change that path unless it hits a chain leading to a red signal on its path. So your stuck train had a clear path through that spot that your other train is now sitting in, when it started its journey. If you'd had a chain signal there, your stuck train would have repathed. No chain signal meant your train didn't know it was in trouble until it go to that red normal signal.

i put a chain signal where the second wagon of the stuck train on the top . will it solve the problem ? i will see.


its looks like solved the problem . İ have many stations whit same setup just this couse problem . interesting.

Whilst I agree that you should have a chain signal just before the stacker, I'm not sure I agree with 5thHorseman's explanation of why.

I would explain things this way. (Note that the following explanation is just the broad strokes. The actual detail of the implementation is more complex. But if you understand the following concepts you should be fine).

A chain signal tells the train "Do not pass, unless you can reserve a route past the next regular signal".

When a train approaches a chain signal, it attempts to reserve its current planned route past the next regular signal. If it can't do that, it asks the pathfinder "Hey is there a better route?"

If the train still can't reserve a route past the next regular signal it will stop at the chain signal and wait until it can reserve a route past the next regular signal. (It will also ask the pathfinder for a better route every few seconds).

So a chain signal just before the stacker effectively means "Stop here, until you can enter one of the stacker bays".

If you really want the details then https://wiki.factorio.com/Railway/Train_path_finding is relevant.

redfoxrommy wrote: ↑

Tue May 05, 2020 10:51 am

i put a chain signal where the second wagon of the stuck train on the top . will it solve the problem ? i will see.

It should.

Zavian wrote: ↑

Tue May 05, 2020 11:32 am

I'm not sure I agree with 5thHorseman's explanation of why.

I'm not either, in fact. Though my explanation comes to the correct conclusion and I can't think of a way it'd lead you astray, I expect I am in fact wrong on that and was coming back here to say it

While you do want that Chain Signal so the train can pick a better path than the one that’s occupied ... that is an inherently bad setup.

Two way track is really only good when you are going to have *exactly* one train on it. You have three in the picture.

You need to go to a two-track system of one-way rails. Thus, inherently bad setup.

Getting what you're showing there is not easy. Trains will repath when they see (i.e. when their braking point reaches) a red signal, so when the incoming train saw the signal it's stopped at, it repathed. And took that path anyway.

Only way I can see that happening is if it was moving slow enough that it was already on the turnout and so had no other option, the train-in-block penalty on the path it picked is guaranteed big enough to make the clear slot look cheaper.

And the only way I see to make *that* happen is ... what, did a train run out of fuel and you had to refuel it? Biters eat a rail segment and you had to rebuild? Did you just build the train right near there? Hop in, back it out, hop out and put it on auto again, it'll pick the correct path.

astroshak wrote: ↑

Tue May 05, 2020 7:36 pm

While you do want that Chain Signal so the train can pick a better path than the one that’s occupied ... that is an inherently bad setup.

Two way track is really only good when you are going to have *exactly* one train on it. You have three in the picture.

You need to go to a two-track system of one-way rails. Thus, inherently bad setup.

I don't consider that setup "inherently bad". Two way track is definitely more throughput limited and harder to extend/expand than a dual track setup, but that doesn't make it inherently bad, just of limited utility compared to a dual track setup.

Besides if you look at the minimap, Redfoxrommy seems to have a dual track setup, so maybe this is only a short spur line to the copper mine. In that role, the single track's throughput limitations might not be an issue.

astroshak wrote: ↑

Tue May 05, 2020 7:36 pm

While you do want that Chain Signal so the train can pick a better path than the one that’s occupied ... that is an inherently bad setup.

Two way track is really only good when you are going to have *exactly* one train on it. You have three in the picture.

You need to go to a two-track system of one-way rails. Thus, inherently bad setup.

It depends on traffic. I use much single track lines in my periphery area, where traffic is mostly occasional ore trains. I build overtake places after about 0.5-1 km. Sometimes train may delay few tens of seconds, but it is not a problem. But of course in crowded central areas I use always two tracks. Difference in traffic handling is much more than double. Double track system can throughput at least 10 times more. But Factorio's block signaling system works perfectly with single track systems too, if built correctly.

I stand by what I said. Two-way track really only works well when you have exactly one train using that section of track.

He has three in that picture.

That is bad design. If you want to use two way track, make sure that only one train has a reason to be using said track. Otherwise, stick with a two track system.

Is it possible to signal the two way track such that multiple trains can be using it? Sure. This does not make it a good design idea. Attempting to do so dramatically increases the chances of deadlocked trains, like the TC has in the pic. Not one of those trains can move (in automatic). Partly that is due to signaling, as shown in the bulk of this thread. But that is also due to having a two-way track as the ingress and egress, while having multiple trains making use of that track. IE - bad design.

astroshak wrote: ↑

Wed May 06, 2020 9:36 am

Is it possible to signal the two way track such that multiple trains can be using it? Sure. This does not make it a good design idea. Attempting to do so dramatically increases the chances of deadlocked trains, like the TC has in the pic. Not one of those trains can move (in automatic). Partly that is due to signaling, as shown in the bulk of this thread. But that is also due to having a two-way track as the ingress and egress, while having multiple trains making use of that track. IE - bad design.

Wrong signaling is different thing than bad design and can be easily corrected. This is also so easy to learn and you do not have safety, economic or any other issues. It is OK as your personal opinion, that you do not like single track system, but not as technical reasoning as far as throughput is not limited. In my opinion single track system is more interesting and realistic. There are takeovers like in real low traffic rail lines. All such give more immersion, which is unfortunately rare thing with Factorio's toy train system.

Hannu wrote: ↑

Wed May 06, 2020 10:51 am

astroshak wrote: ↑

Wed May 06, 2020 9:36 am

Is it possible to signal the two way track such that multiple trains can be using it? Sure. This does not make it a good design idea. Attempting to do so dramatically increases the chances of deadlocked trains, like the TC has in the pic. Not one of those trains can move (in automatic). Partly that is due to signaling, as shown in the bulk of this thread. But that is also due to having a two-way track as the ingress and egress, while having multiple trains making use of that track. IE - bad design.

Wrong signaling is different thing than bad design and can be easily corrected. This is also so easy to learn and you do not have safety, economic or any other issues. It is OK as your personal opinion, that you do not like single track system, but not as technical reasoning as far as throughput is not limited. In my opinion single track system is more interesting and realistic. There are takeovers like in real low traffic rail lines. All such give more immersion, which is unfortunately rare thing with Factorio's toy train system.

It is not a question of liking or disliking two-way, single track systems.

Rather, it is understanding the inherent limits to such sections of rail. They do not work well with multiple trains. It is that simple. Can they work with multiple trains? Yes, but not very well. You yourself said that throughput of a two track system is at least ten times that of a single track system.

Are there ways that TC could change the subject of that pic to make it a better design? Of course. Fixing a flawed design is part and parcel of the game. Recognizing the flaws of a design is also part of it.

And if there are flaws, does that not make it a flawed design?

Going with your 10x, if you only need 10% of theoretical max throughput two-way track is good engineering. Three wagons is 6K ore, three of those trains a minute is enough to keep up with that outpost, the one-track spur's fine, that leaves ten seconds for a train to get in and another ten to get out. Even with coal-fired trains a 1-3 can get through a pretty long stretch of track in ten seconds.

İ think i need to explan my track system. main lines have 2 tracks one way each . this station connecs to it with one two way connecion. why becose i want so .

We could guess that. What people wondered about is why do you combine the way in and out of the station? Have one track in and a separate one out. Then trains won't block each other unless the two intersections are too close.

You can also use linear stackers by just having the trains queue behind each other.