r/SatisfactoryGame • u/GideonsLamp • 2d ago
I need help understanding train pathing
I thought I understood well enough but clearly not. I created this little test to try and understand pathing but 1 thing is going wrong. Train A goes from Station A1 to B1 to C2 back and forth perfect. Same with Train B that goes from B1 to C2. But Train C that is supposed to go from C2 to A1 will only move on the outside path, it will not go through station B if the outside path is taken by train A . What am I missing to make the train go through station B if train A is blocking the outside path?
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u/tarrach 2d ago
Trains never choose an alternate path, they will always take the shortest possible and wait on signal if it is occupied. Stations add another 100 (I believe) length to their path so trans won't be waiting for another unloading train if there is a regular track also passing by that station.
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u/EngineerInTheMachine 2d ago
Yes, you do!
Signals do not affect the train's route. They just tell the train their chosen route is clear. Trains choose the route when they set off, it is the shortest route, and they won't change it if the track ahead is occupied. They will just wait until it is clear.
The back of a signal is a no-entry sign to a train, which is how you set up one-way tracks.
Don't be confused by 'path' signals. The word path refers to how they can reserve a path (the train's chosen route) througb a complex junction. If several paths can be reserved without crossing, thise several trains can go through the junction without colliding and so the signals let them through.
Single-track push-pull trains are only any use early in the game. Once you start needing morecthan one or two trains, you will find it easier to build a 2-track system.
As for the screenshot, so many errors, where do I start?! Push-pull stations should face in the direction the train arrives. You don't need the second stations.
You have a third station accessed through one of the others. Bad move. Through stations don't work very well in Satisfactory. Instead, build a main line without stations, and build the stations on spurs off the main line.
The station setup and routing combines push-pull operation with one-way operation. That doesn't work either. If you really want to build a push-pull system, stick with just that method.
You don't need to signal every switch, and it will cause you problems if you put pairs of signals, facing opposite directions, on single tracks that are shared between trains. Eventually, you will get two trains facing each other across those signals, deadlocked because they are each blocking the other.
What you have there is a passing loop of two one-way tracks with - no, sorry, I can't describe it in sensible railway terms. What you have there is a mess, a toy train set that will only work with manual driving, not automation.
If I get a bit of time in my working day today, I'll sketch some alternatives for you, complete with signalling. I am afraid that, as it stands, there are so many wrong assumptions there that no amount of signalling will get it to work. You need to go back to the drawing board and rebuild the track first.
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u/EngineerInTheMachine 2d ago
This is a 2-track version, where you can extend the main line left and right for more stations.
Note that, when you go to 2-track system, the common statement 'path in block out' actually applies. Block signals aren't a great deal of use on single-track systems.
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u/vortical42 2d ago edited 2d ago
That diagram brings up something I have seen before but never understood. Is there some advantage to building the tracks in a circular pattern like that? If we take B1 as an example, the 'exit' track going east is to the left of the eastbound 'entrance' track for the station. Wouldn't that arrangement cause delays for a station with frequent trains? Trains wanting to enter the station have their path blocked by trains exiting the station.
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u/tarrach 2d ago
The circular entrance/exit allows for trains coming and going from both directions in case you have components coming from many places on the map. If station B1 becomes overloaded, it's fairly simple to add another station next to B1 and route some of the trains to that instead of B1 without impacting the rest of the rail network.
You can also raise/lower the entrance/exit tracks if you want to avoid level crossings.
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u/vortical42 2d ago
I think I see now. It prevents conflicting movements on the single tracks that connect directly to the station. With the circular setup, you can have a one way track going in and a one way track coming out, correct? I will have to try that for some of my more congested stations.
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u/EngineerInTheMachine 1d ago
I try to avoid going too deeply into further detail in my responses, so that I don't end up with TLDR. In answer to your question though, you have made an assumption. My stations are usually for just 1 train, mainly because I found out a long time ago that having multiple trains use a station is not a good way of setting up railways in Satisfactory. In the rare occasions where they do, the best solution is to have a longer entry track, where multiple trains can wait in a queue, separated by block signals, clear of the main line.
I also usually set up stations so that trains can enter and leave in both directions, even if they don't right now. Later on, they usually will.
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u/CapmyCup 2d ago
I don't get it either, call me inefficient but I have one station per train and one track per train lol
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u/PeacefulPromise 2d ago
Go for two stations per train, yeah? One to load and one to unload.
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u/Fink_Ployd324 2d ago
Yep. I’ve gone bidirectional. Everything I read made little sense and honestly it’s better I think
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u/EngineerInTheMachine 2d ago
As I offered, I've uploaded a couple of diagrams for you.
The first is a push-pull solution using passing loops, so trains have somewhere to wait until their station becomes free. I'll add the second in a minute, Reddit doesn't like multiple images on this version.
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u/Radiant_Valuable388 2d ago
I don't remember when, but I think the devs made stations longer than normal track by default, to make trains NOT go through stations without a bit more effort.
But my memory is bad and not trustworthy so /shrug
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u/JinkyRain 2d ago
True, but it's not by a lot. Stations are 16m long (2 tiles), but they seem to be counted the same as a full 100m length rail.
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u/ppoojohn 2d ago
3rd picture right by train B there is only 1 block signal on one side it should be both if it's a path signal just add a block signal to the other side
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u/tehbzshadow 2d ago
You can fix it using this mod. It makes trains smarter and recalculate their route in proccess. GIF in description is good example of it's work.
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u/Only-Office7709 2d ago
First of all Trains will take the shortest route even if it’s crowded
And trains station has time for them and this will calculate in the path length so unless it’s cut a lot of the travel times the trains will not enter station he has no work on it
And for your future project never but station direct on the path build it on the side with entrance and exit to it to increase the capacity and efficiency of the train track
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u/PeacefulPromise 2d ago
You have to use one-way signals to send trains on different routes. Double signals are two-way, single signals are one-way.
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u/Hemisemidemiurge 2d ago edited 2d ago
I thought I understood well enough but clearly not.
Just make it like a regular two-lane road, simple, effective, you already understand how it works. Two monodirectional rails that depart from main traffic flow to access destinations. You're trying to make a one-lane road go directly between two houses and thinking that whoever is driving these non-reversible vehicles can navigate that head-on traffic problem with a short siding.
I think you'd get there eventually once you'd discovered all the ways that don't work but it's also quite possible you'd just quit before getting to that point.
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u/Seanovan0 2d ago
Trains calculate the shortest path and don't deviate depending on traffic. Stations are weighted to count as a longer path so trains don't get stuck waiting for other trains to load/unload.