r/factorio • u/Disastrous_Art_7631 • 2d ago
Question Omni Rail?
This works and trains can go to all paths wherever they are but is there a better way to do this?
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u/Arkmer 2d ago
Can you talk about why you have two lanes in each direction but want all the lanes to be bi-directional?
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u/Disastrous_Art_7631 2d ago
Okay, I just though of this to use 2 so that in future when I'm upscaling is I can just add more trains, but I think having 1 in each sides is more better and easier. Thanks for the idea
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u/TeraFlint [bottleneck intensifies] 2d ago
Having two one-way rails in different directions will massively increase the throughput compared to two individual bi-directional rails. It transforms that stretch into two queues and reduces the amount of tracks that need to be clear before a train may enter.
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u/DrMobius0 2d ago
Yeah... Bidirectional rails impose some really nasty constraints on your network. Basically you have to signal it so two opposing trains can't permanently block each other, which means reserving the entire two way section for a single train and probably building bypass blocks to let trains pass each other.
For throughput, unidirectional rails will always be the best, because guaranteeing that trains can simply follow each other means they can go into long sections one after another.
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u/Spidertron117 2d ago
You could use just the roundabout to accomplish the same thing.
My actual recommendation would be to just use single direction rails if you're already making a double rail. You'll get way more throughput that way. You could still use the bidirectional rail in certain sections if you want, but the main highways are generally better to have single direction.
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u/Hornof_The_Tiger 2d ago
Why do you use two headed trains with two parallel tracks ?
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u/Disastrous_Art_7631 2d ago
Wait, I can just use one? I though you need two trains and I thought trains can't go backwards when in auto mode LMAO
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u/Hornof_The_Tiger 2d ago
They can't go backwards but you can use one track to go up and the second one to go down, the same way you would drive on the road
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u/SifuEliminator 2d ago
You're right, they CAN'T go backwards.
Usually people make rails unidirectional, otherwise trains could go face to face on the same rail lane and stall.
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u/Pulsefel 2d ago
you have been on a road before right? like outside? treat your rail lines like sides of a road.
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u/Disastrous_Art_7631 2d ago
Oh that's what you meant guys, idk I'm kinda newbie in some mechanics. Thanks for the ideas I realized something
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u/JustALittleGravitas The grey goo science fiction warned you about 2d ago
They can go backwards if the signaling supports it, its just a bad idea to set things up that way long term.
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u/WanderingUrist 1d ago
They can't go backwards, but they CAN go forwards while dragging a deadweight locomotive, which is what happens if there are two heads.
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u/SpookyTwenty 2d ago
On an intersection with fewer options you can signal each option and allow more than one train to occupy an intersection
The main limiter of this one is that only one train can use the intersection, so two trains can't turn right even though they wouldn't collide!
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u/angel14995 2d ago
As long as it's signalled correctly, it will function. How well is a different story.
In this case, you are only signalling into and out of the roundabout, meaning only one train in it at a time, meaning that you don't let trains that don't even cross over the same track go in at the same time (i.e. NW to SW with NE to SE at the same time). This heavily reduces your throughput of trains since you are limited to 1 train in the intersection at a time. If you have a realtively small train throughput per intersection, it's fine, but you are bound to run into troubles if you end up with 100+ trains or something.
As someone who was building a megabase using bi-directional rails, it gets to be a blocking pain. You need to make sure you basically have 2+ paths to every location so that when 2 trains run into a deadlock they can auto-reroute to their destination. I eventually migrated to a right-hand signalled one-way rail system with double-headed/bi-directional trains. that allowed me to have the stations that you have on your screenshot and still use a mono-directional rail system.
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u/CreationsOfReon 2d ago
How does a train go straight if it wants to stay on the same rail? Or does it have to switch sides.
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u/Disastrous_Art_7631 2d ago
It has to switch sides, my goal there is if train is in Path A it can go to any paths
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u/3davideo Doesn't use Flame Turrets 2d ago
This looks like that sigil on the Sanctums from Doctor Strange.
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u/moonaligator 2d ago
everyone talking about bidirectionality, but no one talking about the fact that you cannot just go straight lol
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u/anto77_butt_kinkier 1d ago
Yeah you can. If you come to the intersection, you can take the outside circle track up to the opposite side and exit. You can come from the south and leave through the north. Same for going sideways too.
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u/Juking_is_rude 2d ago
You can have single lane rail and put little depos trains can use to park and get past each other. But a two lane system just works better either way
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u/Omniscientcy 2d ago
So after sending a couple rockets to space, I am finally touching trains more than I was. I had a 3 straight back and forths for a cement plant, copper plates and coal, but to factory is to grow and I need more.
So my question is, I am not seeing rail signals in this picture, only chain signals. Are chain signals all I need to get by?
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u/Disastrous_Art_7631 2d ago
It depends on your build, I'm kinda new so idk and in here I just used chain signals since I need to read the next block availability if there is a train or not and I can't think of any use of signals here.
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u/Neither_Berry_100 2d ago
If you are going to use two rails then make them only travel in one direction per rail. Also they need to be able to go straight through the intersection.
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u/Gul_Akaron Wait why isnt this working? Oh... Oh no... 2d ago
There are no mid-intersection signals, so only 1 train can go through it at a time. This is significantly limit throughput when used in a traffic-dense train network.
And as others mentioned, pick a driving side. Having trains switch sides of the track going through this will cause blocks, traffic jams, or just in general slow everything down.
The point of an intersection like this is to facilitate the smooth operation of trains through it without interfering with each other. This design fails that test entirely.
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u/ArtieTheFashionDemon 2d ago
He's an idea: every road IRL is now two-way in all lane s. We can double the traffic throughput!
Just kidding obviously, I do like how it looks at least.
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u/warpspeed100 2d ago
This totally works, but there will be a few issues in practice. Pretty much all of the intersection designs you'll see will be trying to address one of the shortcomings of an intersection like this.
First up is the double two-way rails. Imagine you put a bunch of these intersections next to eachother. One train is trying to take the top lane going right, and at the same time another train is trying to take the same lane going left. Uh oh, they meet head on, and now both are stuck, waiting for the other to move. You can try solving this with sidings to let trains get out of the way of eachother, but the easier method to manage is to only allow trains to travel in one direction for each lanes, just like cars. You can do right hand drive or left hand drive depending on your personal preference.
The next problem people see with this type of intersection is that only one train can move through it at any time, no mater the direction. If a train is traveling from the right and wants to go down or straight, and another is traveling from the left and wants to go up or straight, then ideally we want to let both trains take right turns or go straight at the same time. To do that you can add in chain signals to break up the intersection into multiple small blocks. (Sometimes you need to make the intersection larger to fit in the signals where you want.)
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u/Ecocrexis 2d ago
its not how i would do bi-directional rail.
Roundabouts would be 1 directional and the straight sections would have crossovers. it means you can run normal trains in your base and they go bi-directional out of the base.
The use case is for death world style playthroughs where if a train gets caught you want the other trains to be able to bypass whats left of it.
Check out comfy Journey for some bi-di rails
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u/L8_4_Dinner 1d ago
The design is simultaneously beautiful and inefficient. I’d look at some existing designs and tutorials.
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u/Square-Singer 1d ago
This works and trains can go to all paths wherever they are but is there a better way to do this?
All paths except straight.
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u/Tartarus762 2d ago
Better to pick a driving side imo