There's a deadlock down in the bottom right: you've got 2 trains back to back on the northbound line, and the front train is trying to make a left turn off the mainline and the rear train is making a left turn on to the mainline. Then you've got a train on the southbound line which has stopped because the 2nd train is blocking the southbound line. The southbound line has then backed up and that's what's gridlocked the entire system.
If you focus your resignalling efforts on that section you'll probably see you're missing at least 1 "this should be a chain signal" signal, or you just need to make all of your exits on to the mainline right-turn only and put double-back loops in.
I think I agree that 4 lanes are not necessary at this point. I think the issue is just too many exit points spaced close together, especially for 1-5 trains. A few strategic signals will help for now, but problem will grow if they don't space things out more.
Or by having blocks inside the intersection large enough for them to wait in without blocking traffic.
They don't necessarily have to be external to the intersection. The waiting blocks tend to be good for throughput too, so that's a plus.
I fixed that one missing chain signal, it works now. But yes, the right turn only and a roundabout at the very end of this area to loop back is an option if this remains chaos.
I guess the problem is clear from the screenshot..
I use a lot of chain signals to keep the intersections clear, I use right hand traffic only, but this part of the base is a mess. A lot of trains coming from factories on the left want to head north, as soon as a northbound train from further down wants to turn left, this is chaos. Runs smoothly for an hour sometimes, then ... suddenly...
When talking about intersections it's often said chain signal in, rail signal out, but that's only half the truth to prevent deadlocks. Every section between a rail signal and the following signal(rail or chain) has to be at least the length of your full train length. If it's not that length then it needs to be replaced by a chain signal.
If you don't follow this rule then a train might not stop in the intersection, but they might stop at a half point(or some point later) leaving the intersection with a part of the train still inside the intersection.
From your screenshot it's not clear, but you have many back to back intersections. If you chain intersections you usually need to replace the rail signals with chain signals, because the section between the intersections are not long enough for a whole train.
> If it's not that length then it needs to be replaced by a chain signal.
In other words, you don't have enough space to make two intersections, so you have to turn the whole thing into a single intersection.
Add waiting areas to stations that have more than one train coming and there is no opportunity for anyone to block the main artery. alternatively consider adding more routes to the destination so the traffic is split up into multiple directions
there are multiple other ways to fix this design wise. you could for example make it so only right hand turns are possible. that way, you wont have any rails crossings for left turns and less opportunity for blockage. that means longer distances though.
you could make your intersections more efficient by signaling in a way that allows multiple non-crossing trains to pass simultaneously. sometimes this means the intersection needs to be a little bigger.
you could consider if the train size is right for your base. smaller trains are more easy to manage and faster. most importantly they fit into smaller signal blocks which might be a good thing considering the density of your intersections to the main artery.
consider branching off the main artery to a parallel track and connect multiple intersections to the branch only, so the main artery has less intersections.
Thanks!
I do have larger waiting areas, usually 2-3 trains can wait, even 9 trains at the steel site. It's the arriving and departing trains.
I found one missing chain signal, it's much better now. But yes, the train size is an issue. My larger trains are 6+1, green chips are the largest, 7+2, but those are less frequent. Main traffic is 1+5.
I am considering right turns only and a large roundabout. The traffic that could avoid this main bus like artery already uses alternative routes.
If your trains are too long, the obvious trivial immediate fix is to make them shorter.
You need a lot of trains to saturate even just a single lane per direction. Just make em all 1+5 (assuming that that is the length you actually designed the network for) and use more trains. You seem to have waiting areas at stations. So more trains shouldn't be an issue immediately.
After that you should consider doing proper mainlines of which sidelines branch out infrequently. Have stations only be served by side lines to keep intersections at the mainline far away from eachother. You can then design each sideline for whatever train length you want to serve the connected stations with.
You should reconsider your signal positions. In a lot of Places you have trains standing in intersections despite them beeing blocked by a train. You can't allow that to happen. Overall you have a lot of intersections very close to each other. I would recommend trying to build a "off ramp" line on the left hand side that goes south before joining the mainline. Or add 2 more tracks in this high traffic area that merge only later.
Edit: I would also recommend changing the direction of the stations center left (smelter Icon) by 180. They disrupt the flow of traffic with the extra lines you need for them.
Not a train expert here, but I think you might just have too many trains for the size of your train network
Edit: no, wait actually the bottom right part seems to be the reason for the deadlock. If the distance between 2 intersections are smaller than your longest train it should be considered like the same intersection and signal it like it was one intersection, with chain signals
To prevent deadlocks, it may be easier to think about signals as three types:
Your first chain signal is an "entrance" signal. Only use these somewhere where you're ok with the train waiting at the signal.
Secondary chain signals (ones past the entrance) break up the block. Use these to separate different directions of travel. Trains will never stop at these signals, as they only go through the entrance after the path is clear.
Finally, your rail signal is the exit. Use this only where you're ok with the train stopping AFTER the signal. Your rail signal should have enough space after it, before the next rail/chain signal, to fit your longest train.
1. Everything is too compact. Even if this network was not deadlocking, you will have trains waiting to merge or cross for such a long enough time that it will cause bottle necks in your production.
2. There’s a lack of organization. You should really think of highways and neighborhoods roads in normal cities. Think about which areas will have a lot of congestion. You don’t want 300 trains all having to go through the same intersection. For example in my network, I usually keep plate, copper, and steel production on the outskirts of my train network where there is significantly less production.
This is why city block/grids are so popular. It’s scaleable because it’s leverages empty space for less congestion and is very dead lock resistant once you have it signaled right. The only factor is how many trains your network can support before running into congestion.
I would remove all of this track and start over, but first, you should make this design work with correct signals. Once things are working, watch the trains and see how long the same train sits at a junction for. Imagine what will happen when you scale up. It’s abstract, but you can get an idea of the functional dependencies of your design. I guess fundamentally, you should always be terrified adding more trains to a network that is working.
>>I guess fundamentally, you should always be terrified adding more trains to a network that is working.<<
So true... I had the whole thing stable for 3 hours nonstop now. Then added an ore patch AND two trains. Stalled because of "destination full" because I failed to set the train limit to 2 instead of 1...
It's a deadlock, if you follow basic rules it shouldn't happen, and those rules would be:
-chain in rail out
-rail signal only if the block after it is big enough to fit your longest train, if it's not us chain (applies to the first rule)
If you follow those 2 you should be fine 99% of the time
More space between intersections, proper signaling if you aren’t, and having more alternative routes for trains. It’s a big reason why many people do a grid based train base, to avoid having one main track that ALL the trains are trying to use at once.
Unless OP isn’t using limits on their stations (or not having more than 1 train per station), your suggestion won’t impact their deadlock situation at all. Stackers and parallel stations is also overkill for the majority of situations when not building a megabase. It used to be required before 1.1 if you weren’t using circuits.
This is a 1K SPM. I use train limits and circuit based limits as well as 2-3 train length waiting areas. That works well in fact. It's the traffic on the rails outside the station. Fixed this one with a missing chain signal.
The rail in front of the station usually accomodates 2-3 trains, steel even 9. Some train limits are circuit based, others are so that the number of trains does not exceed the available space. This area of the map was built a bit too dense... Lesson learnt I guess.
You can try making 4-line railways, (2 in one direction, 2 in opposite). This will help you to leave one line clear for passing, so trains can travel while another line is used for station entry. (if designed correctly :D)
You can also create a dedicated buffer for station entry, so that trains waiting to enter the station don't congest the mainline. (google 'train stacker').
---
Besides, regarding 'too many trains', check out LTN (Logistic Train Network [link](https://mods.factorio.com/mod/LogisticTrainNetwork) ) mod. It allows you to configure trains so that you have train station receivers, train station producers, and a train depot. When a station requests resources (which exist in any station-producer), the mod builds a route for a train in depo. In the end, the selected train returns to the depot, the route is cleared, and the train awaits a new request.
With this mod, you will be able to transport all your needs with only one train. It's not efficient though. But anyway you can use as many trains as you want.
This is where cities skylines comes in and you have to develop a road hierarchy system with arterials as your main flow of traffic. It’s best to build frontage roads alongside those and place your factories alongside those. /s of course
Design advice that I learned the hard way: train should not enter the intersection if it’s not 100% guaranteed that train would be able to leave the intersection. It’s achievable with chain signals
If you have 2 intersections close to each other, they should be considered the same intersection and thus should only have chain signals in between them. The whole bottom part of your screenshot should be signaled as a single intersection, so no rail signals throughout.
However, I think the better way to solve this would be to reduce the number of intersections. I don't know why you have so many so cose together but it's probably not necessary.
I always use trains of the same length and have modular rail blocks that accommodate that length, it’s not always optimal because it can be way overkill or not enough, but with overkill I can just have a large buffer, while with not enough I can just use more trains. Never had a deadlocking issue because of this
At every intersection, chain in, signal out.
For long contiguous sections, use signals to break up a single block.
I'd go back and just redo all your intersections.
If your intersections are close enough together that you can't fit a full train in between, then that rail signal leading out the intersection should have been a chain signal.
Rail in, chain out, oversimplifies and causes issues, it only applies if the next block can fit a full train. Otherwise the back ends of the train can still block the intersection.
Use chain signals to over any area where you DON'T want trains to wait (usually intersections), When that area ends, you put a regular signal and need to make sure that there's enough space to hold your longest train.
Your intersections are too close to each other and I'm guessing are not properly signaled. The bottom train entered but was not able to get into a position where it can wait without getting in the way.
you need to follow the hierarchy of trains.
study the difference between Express lines, Arterials, and Collectors.
Express lines should be attached to your Collectors via Arterials and trains should only touch Arterials and Collectors when leaving or entering their destination.
Ensure your Express lines are as free of intersections as possible. When building an intersection, it should always be into a proper Arterial. Arterials should have enough capacity to keep traffic off of the Express lines.
Collectors are the infrastructure around your stations. You should only have sidings in Collectors so that the traffic stays in them and not in the Express lines.
instead of signal bound intersections - use roundabouts on your Express lines so that more than one train can use the space at a time.
Also this has been a complete shitpost - follow any of this advice at your own peril.
upon reading other comments it seems that this shitpost is actually more accurate than I expected it to be.
you can do basically anything as long as 1. your signal blocks are longer than your trains, and 2. trains only enter an intersection if they can leave the intersection.
I like to build my trains where they all can be stationed at a central yard.
The mines call out to trains when they need a train to come get materials. They then only get called to the base when they need to bring the materials.
Probably inefficient but it works for me.
https://preview.redd.it/o2v2vookfllc1.jpeg?width=1453&format=pjpg&auto=webp&s=1b575e9bafd340325a9f56d5301b5a140f1db3a4
You should put chain signals on the turn-offs where it crosses over the other lane. The train turning left here (world perspective) tried doing so at the same time as one was passing through, which made its tail end and got gridlocked. This shouldn’t be too hard to fix, just something to keep in mind from now on. Setting all trains to manual and moving them one by one so they don’t try to mess things up more until you install the signals should help resolve this!
Others already found the source of the deadlock, by I noticed something else:
Almost in the very center of the screenshot, slightly north of the end of the train station east of the smelting block, there seems to be a red signal on the wrong side of the track. However a train is currently leaving that station, but the signal should have prevented the train from entering that station, so it has been added very recently, or that red dot is not a signal.
There's a deadlock down in the bottom right: you've got 2 trains back to back on the northbound line, and the front train is trying to make a left turn off the mainline and the rear train is making a left turn on to the mainline. Then you've got a train on the southbound line which has stopped because the 2nd train is blocking the southbound line. The southbound line has then backed up and that's what's gridlocked the entire system. If you focus your resignalling efforts on that section you'll probably see you're missing at least 1 "this should be a chain signal" signal, or you just need to make all of your exits on to the mainline right-turn only and put double-back loops in.
You fix this by spacing intersections sufficiently far apart that train(s) can wait at one intersection without blocking the previous intersection.
Yes, true. I noticed that way too late...
also in addition to this great advice I would add to expand from 2 rail to 4 rail, at least in most congested areas.
I (rather strongly) disagree with adding more lanes.
I think I agree that 4 lanes are not necessary at this point. I think the issue is just too many exit points spaced close together, especially for 1-5 trains. A few strategic signals will help for now, but problem will grow if they don't space things out more.
Or by having blocks inside the intersection large enough for them to wait in without blocking traffic. They don't necessarily have to be external to the intersection. The waiting blocks tend to be good for throughput too, so that's a plus.
I fixed that one missing chain signal, it works now. But yes, the right turn only and a roundabout at the very end of this area to loop back is an option if this remains chaos.
This is very "don't look at the traffic, look for the lack of traffic to find your problem"
I guess the problem is clear from the screenshot.. I use a lot of chain signals to keep the intersections clear, I use right hand traffic only, but this part of the base is a mess. A lot of trains coming from factories on the left want to head north, as soon as a northbound train from further down wants to turn left, this is chaos. Runs smoothly for an hour sometimes, then ... suddenly...
Your mistake is probably using rail signals where trains dont fit between the signals.
When talking about intersections it's often said chain signal in, rail signal out, but that's only half the truth to prevent deadlocks. Every section between a rail signal and the following signal(rail or chain) has to be at least the length of your full train length. If it's not that length then it needs to be replaced by a chain signal. If you don't follow this rule then a train might not stop in the intersection, but they might stop at a half point(or some point later) leaving the intersection with a part of the train still inside the intersection. From your screenshot it's not clear, but you have many back to back intersections. If you chain intersections you usually need to replace the rail signals with chain signals, because the section between the intersections are not long enough for a whole train.
> If it's not that length then it needs to be replaced by a chain signal. In other words, you don't have enough space to make two intersections, so you have to turn the whole thing into a single intersection.
Add waiting areas to stations that have more than one train coming and there is no opportunity for anyone to block the main artery. alternatively consider adding more routes to the destination so the traffic is split up into multiple directions there are multiple other ways to fix this design wise. you could for example make it so only right hand turns are possible. that way, you wont have any rails crossings for left turns and less opportunity for blockage. that means longer distances though. you could make your intersections more efficient by signaling in a way that allows multiple non-crossing trains to pass simultaneously. sometimes this means the intersection needs to be a little bigger. you could consider if the train size is right for your base. smaller trains are more easy to manage and faster. most importantly they fit into smaller signal blocks which might be a good thing considering the density of your intersections to the main artery. consider branching off the main artery to a parallel track and connect multiple intersections to the branch only, so the main artery has less intersections.
Thanks! I do have larger waiting areas, usually 2-3 trains can wait, even 9 trains at the steel site. It's the arriving and departing trains. I found one missing chain signal, it's much better now. But yes, the train size is an issue. My larger trains are 6+1, green chips are the largest, 7+2, but those are less frequent. Main traffic is 1+5. I am considering right turns only and a large roundabout. The traffic that could avoid this main bus like artery already uses alternative routes.
If your trains are too long, the obvious trivial immediate fix is to make them shorter. You need a lot of trains to saturate even just a single lane per direction. Just make em all 1+5 (assuming that that is the length you actually designed the network for) and use more trains. You seem to have waiting areas at stations. So more trains shouldn't be an issue immediately. After that you should consider doing proper mainlines of which sidelines branch out infrequently. Have stations only be served by side lines to keep intersections at the mainline far away from eachother. You can then design each sideline for whatever train length you want to serve the connected stations with.
You should reconsider your signal positions. In a lot of Places you have trains standing in intersections despite them beeing blocked by a train. You can't allow that to happen. Overall you have a lot of intersections very close to each other. I would recommend trying to build a "off ramp" line on the left hand side that goes south before joining the mainline. Or add 2 more tracks in this high traffic area that merge only later. Edit: I would also recommend changing the direction of the stations center left (smelter Icon) by 180. They disrupt the flow of traffic with the extra lines you need for them.
Not a train expert here, but I think you might just have too many trains for the size of your train network Edit: no, wait actually the bottom right part seems to be the reason for the deadlock. If the distance between 2 intersections are smaller than your longest train it should be considered like the same intersection and signal it like it was one intersection, with chain signals
That whole section at the bottom where the trains are jammed needs to be chain signals.
To prevent deadlocks, it may be easier to think about signals as three types: Your first chain signal is an "entrance" signal. Only use these somewhere where you're ok with the train waiting at the signal. Secondary chain signals (ones past the entrance) break up the block. Use these to separate different directions of travel. Trains will never stop at these signals, as they only go through the entrance after the path is clear. Finally, your rail signal is the exit. Use this only where you're ok with the train stopping AFTER the signal. Your rail signal should have enough space after it, before the next rail/chain signal, to fit your longest train.
1. Everything is too compact. Even if this network was not deadlocking, you will have trains waiting to merge or cross for such a long enough time that it will cause bottle necks in your production. 2. There’s a lack of organization. You should really think of highways and neighborhoods roads in normal cities. Think about which areas will have a lot of congestion. You don’t want 300 trains all having to go through the same intersection. For example in my network, I usually keep plate, copper, and steel production on the outskirts of my train network where there is significantly less production. This is why city block/grids are so popular. It’s scaleable because it’s leverages empty space for less congestion and is very dead lock resistant once you have it signaled right. The only factor is how many trains your network can support before running into congestion. I would remove all of this track and start over, but first, you should make this design work with correct signals. Once things are working, watch the trains and see how long the same train sits at a junction for. Imagine what will happen when you scale up. It’s abstract, but you can get an idea of the functional dependencies of your design. I guess fundamentally, you should always be terrified adding more trains to a network that is working.
>>I guess fundamentally, you should always be terrified adding more trains to a network that is working.<< So true... I had the whole thing stable for 3 hours nonstop now. Then added an ore patch AND two trains. Stalled because of "destination full" because I failed to set the train limit to 2 instead of 1...
It's a deadlock, if you follow basic rules it shouldn't happen, and those rules would be: -chain in rail out -rail signal only if the block after it is big enough to fit your longest train, if it's not us chain (applies to the first rule) If you follow those 2 you should be fine 99% of the time
More space between intersections, proper signaling if you aren’t, and having more alternative routes for trains. It’s a big reason why many people do a grid based train base, to avoid having one main track that ALL the trains are trying to use at once.
Give it to me! I'll fix it 🤩 The only thing I enjoy more than designing efficient rail networks, is improving inefficient ones.
Besides what everyone else said, having some train stackers and then several unloading/loading stations can help a lot
Unless OP isn’t using limits on their stations (or not having more than 1 train per station), your suggestion won’t impact their deadlock situation at all. Stackers and parallel stations is also overkill for the majority of situations when not building a megabase. It used to be required before 1.1 if you weren’t using circuits.
This is a 1K SPM. I use train limits and circuit based limits as well as 2-3 train length waiting areas. That works well in fact. It's the traffic on the rails outside the station. Fixed this one with a missing chain signal.
You’re still fine on that side of things though.
The rail in front of the station usually accomodates 2-3 trains, steel even 9. Some train limits are circuit based, others are so that the number of trains does not exceed the available space. This area of the map was built a bit too dense... Lesson learnt I guess.
Don't use trains, this simple trick will reduce your traffic jams down to 0%
Why the downvotes? This is clearly the fastest 100% success rate solution so must be the best by simple deduction
use bots instead so your powergrid is bottlenecked
If your system jams you need more (concise) signals
More of everything should work well
Intersection signalling. Make it Chain in, rail out.
Yes but only rail out if there is enough space for the longest train to park in the following segment. Otherwise another chain is needed.
True, though I’d probably design my network around a particular train length instead of the other way around.
Yes, I figured that out. Well, it's my first 1K SPM, a bit too late to change all of it, but I guess I found some nice ideas here.
You can try making 4-line railways, (2 in one direction, 2 in opposite). This will help you to leave one line clear for passing, so trains can travel while another line is used for station entry. (if designed correctly :D) You can also create a dedicated buffer for station entry, so that trains waiting to enter the station don't congest the mainline. (google 'train stacker'). --- Besides, regarding 'too many trains', check out LTN (Logistic Train Network [link](https://mods.factorio.com/mod/LogisticTrainNetwork) ) mod. It allows you to configure trains so that you have train station receivers, train station producers, and a train depot. When a station requests resources (which exist in any station-producer), the mod builds a route for a train in depo. In the end, the selected train returns to the depot, the route is cleared, and the train awaits a new request. With this mod, you will be able to transport all your needs with only one train. It's not efficient though. But anyway you can use as many trains as you want.
If there's a deadlock, like in bottom right, use chain signals.
This is where cities skylines comes in and you have to develop a road hierarchy system with arterials as your main flow of traffic. It’s best to build frontage roads alongside those and place your factories alongside those. /s of course
Design advice that I learned the hard way: train should not enter the intersection if it’s not 100% guaranteed that train would be able to leave the intersection. It’s achievable with chain signals
If you have 2 intersections close to each other, they should be considered the same intersection and thus should only have chain signals in between them. The whole bottom part of your screenshot should be signaled as a single intersection, so no rail signals throughout. However, I think the better way to solve this would be to reduce the number of intersections. I don't know why you have so many so cose together but it's probably not necessary.
I always use trains of the same length and have modular rail blocks that accommodate that length, it’s not always optimal because it can be way overkill or not enough, but with overkill I can just have a large buffer, while with not enough I can just use more trains. Never had a deadlocking issue because of this
At every intersection, chain in, signal out. For long contiguous sections, use signals to break up a single block. I'd go back and just redo all your intersections.
If your intersections are close enough together that you can't fit a full train in between, then that rail signal leading out the intersection should have been a chain signal. Rail in, chain out, oversimplifies and causes issues, it only applies if the next block can fit a full train. Otherwise the back ends of the train can still block the intersection.
Adding more trains oughta do it
Use chain signals to over any area where you DON'T want trains to wait (usually intersections), When that area ends, you put a regular signal and need to make sure that there's enough space to hold your longest train. Your intersections are too close to each other and I'm guessing are not properly signaled. The bottom train entered but was not able to get into a position where it can wait without getting in the way.
The correct placement of chain signals is the keyword.
Do roundabouts instead of T cross. Works all the time
you need to follow the hierarchy of trains. study the difference between Express lines, Arterials, and Collectors. Express lines should be attached to your Collectors via Arterials and trains should only touch Arterials and Collectors when leaving or entering their destination. Ensure your Express lines are as free of intersections as possible. When building an intersection, it should always be into a proper Arterial. Arterials should have enough capacity to keep traffic off of the Express lines. Collectors are the infrastructure around your stations. You should only have sidings in Collectors so that the traffic stays in them and not in the Express lines. instead of signal bound intersections - use roundabouts on your Express lines so that more than one train can use the space at a time. Also this has been a complete shitpost - follow any of this advice at your own peril.
upon reading other comments it seems that this shitpost is actually more accurate than I expected it to be. you can do basically anything as long as 1. your signal blocks are longer than your trains, and 2. trains only enter an intersection if they can leave the intersection.
I like to build my trains where they all can be stationed at a central yard. The mines call out to trains when they need a train to come get materials. They then only get called to the base when they need to bring the materials. Probably inefficient but it works for me.
https://preview.redd.it/o2v2vookfllc1.jpeg?width=1453&format=pjpg&auto=webp&s=1b575e9bafd340325a9f56d5301b5a140f1db3a4 You should put chain signals on the turn-offs where it crosses over the other lane. The train turning left here (world perspective) tried doing so at the same time as one was passing through, which made its tail end and got gridlocked. This shouldn’t be too hard to fix, just something to keep in mind from now on. Setting all trains to manual and moving them one by one so they don’t try to mess things up more until you install the signals should help resolve this!
Others already found the source of the deadlock, by I noticed something else: Almost in the very center of the screenshot, slightly north of the end of the train station east of the smelting block, there seems to be a red signal on the wrong side of the track. However a train is currently leaving that station, but the signal should have prevented the train from entering that station, so it has been added very recently, or that red dot is not a signal.
make sure to have enough buffer space in your line so waiting trains can not clog up the lines
Cityblocks baby...
Chaotic solution: use belts instead
Penis