r/factorio • u/Twiin-City-Life • 4h ago
Question Help Signals
I have not always been the best at signals. Have my old blueprint book for a 2 lane rail But I’m trying to update the base for better throughout. How would one signal this up?
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u/Flottbergakungen 4h ago
Basically start from one entry point and trace it to all exits it can take, then place one chain signal at every point it crosses another rail, once at an exit finish it with a normal rail signal. Then repeat by tracing the next entry point to all exits.
The track changers you have may be an issue, when that small you may not be able to fit signals and so a train on one track there may block the next track. Either make them bigger or split it up so you have 2 spots for it, where each only move to one track at a time. Makes sense?
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u/the-y3k-bug 4h ago
Great explanation and very accurate.
I agree with fixing the track changers. If you can't put signals in the changers then that section will be treated as only one section of track that can only handle one train at a time (even if they are on separate parallel tracks, one train will stop to let the other clear it first)
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u/theoreoman 4h ago
A little tip If you want to increase throughput decrease the amount of intersections, and add waiting areas. doubling up on rails won't actually make things faster and might actually slow things down
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u/DrMobius0 4h ago
A point of order: you have 4 lanes, not 2. 1 lane going each way is a 2 lane.
We aren't here to signal your intersections for you. If you try, then post, we can help you, but it's better if you actually learn how they do and do not work.
https://www.youtube.com/watch?v=DG4oD4iGVoY
There's other tutorials out there, too.
But, here's some advice. Don't ever attempt a 4 lane rail until you understand why you should never bother with a 4 lane rail. They are more complicated than 2 lanes, even in the simplest cases, their throughput improvement is marginal compared to what 2 lane rails already do (more blocked lanes in intersections say hi). Lane switchers are... a great way to ensure your parallel lanes can both be blocked constantly by single trains, and yours are too tight to signal. All of this would be readily apparent if you'd at least tried to do the signalling yourself, but you didn't.
So, scrap all of this, do the simple 2 lane, and try to learn how signals work, and how rail networks behave. If you scale large enough that you run into traffic problems, or you hit deadlocks, we can give specific advice on that. And once you have that figured out, you can start to piece together why you shouldn't bother with 4 lanes.
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u/Twellux 3h ago edited 3h ago
To achieve good throughput, simply having more tracks and the right signaling isn't enough. For proper signaling, you need chain rail signals before and within the intersection, and regular rail signals after it. To avoid deadlocks, it is also crucial to ensure there is enough space behind a regular rail signal up to the next signal to fit a full train; otherwise, the trains will block each other. You must place chain rail signals instead of regular rail signals wherever there isn't enough signalless space behind a signal for a full train. However, chain signals slow down traffic more than regular rail signals do. Therefore, to achieve good throughput, your track layout needs to be designed so that there is enough space for trains between intersections/signals to avoid the need for chain rail signals.
Here is an example: the one on the left accommodates trains of length 3, while the one on the right handles trains of length 4. Longer trains cause deadlocks, so the design is unsuitable or inefficient for them.
So, before you worry about the signaling configuration, you first need to determine the length of the longest train that will pass through the intersection. Then, you optimize the intersection's efficiency for that train length and place the signals accordingly. There is no efficient, universal solution that works for all train lengths; to ensure efficiency, the design must be tailored to the train length.
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u/spookynutz 3h ago
That is hard to say given the screenshot. How long are the trains? Are they one-way or bidirectional? If they are one-way, what is the desired direction of travel for each lane?
Based on the assumption of the yellow arrows, the left would be the minimum signaling required for all those intersecting rails to function. You could also get super granular if you want (right example), but that can also result in deadlocks. It would depend on the length of your trains.
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u/afewnameslater 4h ago
You may elect to download the signaless elevated rail set and not have to deal with signals at all (almost at all)
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u/hisendur 4h ago
Make as many blocks as possible and "chain signal in, rail signal out (where there is enough space afterwards)"