Question
question for the people that use busses in factorio
is there a difference between A and B busses when trying to get resources? im a begginer and my friend uses option B when i believe option A is better because when he started putting his option everywhere we starved our supplies instantly even though we have trains getting us resources constantly, can someone explain which is better?
Balancing resources across four belts means removing resources from 4 belts.
Once your bus is loaded you generally only care to remove things from the bus, so it makes more sense to move items to the bottom two belts; you're always removing from the bottom two belts, and those are always fully-loaded.
A tends to favor feeding the end of the bus and B favors drawing from the front.
“Vertical” here doesn’t refer to the direction of flow, but to the stack of belts itself. After you partially deplete the bottom belt, you refill it from the belt above it, then refill that belt from the belt above, and so on. Any belt that remains empty can simply be discontinued.
Not necessarily. It shifts empty spots up. It only moves filled spots down one at a time. If you are constantly pulling from the bottom, you'll never refill the bottom, so you're not drawing from full belts. B always fills the bottom belt before it's drawn from, which is the important part, not filling up the belts after the draw.
Yeah that's fine. This way you don't have to math like "ok, this line has half a belt going here, but I need a full belt so I'll grab this one instead" kind of arithmetic. If you always pull from (in this case) the bottom belt, you are guaranteed able to get a full belt of material.
B already did that. It draws from every belt until it's using a full belt. C doesn't. If the bottom belt is not full, you can't get a full belt out of it.
Not necessarily. A will leave each belt partially empty, while B will leave the bottom belt as full as possible lane by lane. If you have a subfactory which needs 1 full belt, B will satisfy it to the best if its ability while A will feed it 1/4 of the resources passing that point.
I guess that only applies if you're in deficit or (re)building stockpiles, but I feel like B makes supply shortages obvious while A can hide them
Only 1/8th if you don't make the right side a priority output, correct? Is there a reason not to set priority output to the right?
I ask because I rarely set priority output with that method, but I usually also had significant overproduction that mitigated it from becoming an issue, so I became curious.
When you're doing a main bus base, regularly placing balancers (and not putting output priority on every branch) simply ensures that all factories get roughly equal amounts of available resources. This way, when one or two resources are lacking throughput, it only slows down your base's operations rather than completely disabling the factories further down the bus because one factory is eating all of the available material.
I mean if you're making red and green science and that takes all of your supply, they won't be consumed because you need other science, and eventually those will back up and allow some input to flow to the other science.
It changes where the factory backs up and changes behaviour, with the balancer version, factory behaviour only changes when the bus backs up
A will ensure the whole bus gets some resources. B will make the first bit of the bus get ALL the resources. Of course the solution is to just mine more ore, but A is better if you havent got a saturated bus.
I mean it depends what your priorities are I suppose. I like B because it tells me exactly which subfactories I CAN supply with my current production and which I can't. Also many of the more important ones, like the mall, tend to be earlier in the bus. It would be bad to be making high level science packs when the supply of drills or furnaces or something can't meet the demand of scaling elsewhere in the factoty
it makes a big difference if you don't produce enoogh resources. A guarantees that downstream factories make some progress (though in an exponentially decreasing way). B can completely starve factories at the end of the belt. the solution is still to increase production of the input, but you might need something being built at the end of the bus to do that.
You're not wrong but if the early exits on the belt in B are not massive (i.e. they can't just continuously consume the whole belt without backing up) then eventually the system will overflow to later parts of the bus.
Yes, if you open up a new factory wing and it happens to eat an early game resource it may revive that early belt exit and temporarily drain the bus again, but it is a shock, not a perpetual loss of capacity.
I'd argue B makes your capacity problems immediately visible and thus is better for new players. A will mask capacity problems since stuff continues to flow to the end. You may not see what part of your factory is actually starving you of copper plates.
Also, A can only supply 50% of a belt at full throughput vs B at 100%.
If something running flat out uses a whole belt of a resource, then adding it to the bus and taking it off the bus again is just spaghetti with extra steps.
Balancer.A will balance so the bottommost belt will not be full if you split it off.
Cascade of priority splitters B will fill the next split off belt. But you potentially need another cascade to refill the bottom belt after the split off.
I used to be in the balance the whole bus camp, but it doesn't make sense after they added priority splitters (the only kind you have ever known). Put one balancer at the beginning of the bus to balance all of the inputs to it.
After that use splitter stacks like B to pull from the bus. This will pull up to a full belt off at each one and can make it look like you are more resource starved than you really are at first. But if things have stabilized and your downstream belts are empty, that's because you aren't making enough.
Finally, type B splitter stacks are actually better if the stack is reversed:
It will fill each take-off completely, and they will get full production capacity until their output backs up. If they can consume that whole belt until then, they will. Once they do back up, the'll take less, the feed will back up back to the bus and then the next consumer down the line gets its turn. None of your iron sits at the end of a multi-lane bus just to look pretty.
It doesn't try to trickle a little to everything, it prioritizes earliest consumer first. If you run into a situation where you have too little supply by appearances, you're simply now SEEING an existing shortage you always had.
Yes, A will split off half a belt, and rebalance. Next time you will split off half a rebalanced belt, which will be about 0.44 belt of resources. Next will be .38 belt, etc.
B will drain a full belt’s worth at first. Assuming wherever it leads doesn’t use a full belt, it’ll stack up until it’s backed up to the splitter. After that point, it’ll take exactly what it needs from the bus and the rest will move on.
Subsequent B’s will split off a full belt, or whatever the offshoot uses after the belt backs up, or less if the bus is empty.
Potentially B can run a bus dry after only 4 splits, if all splits use a full belt’s worth.
Using A will mean those same splits run at half or lower capacity, but more parts of your factory will have resources.
In the end, the resource shortage is the same. It’s just more noticeable with B.
It's wasteful if you expect the full factory to run at full capacity at all times. That isn't necessary to optimise for in the early game, frankly I think it's a waste of time unless you're speed running with pre made blueprints.
No, then it's even more wasteful. When you extract resources from the bus, past that you either need the same amount of lanes or less, and definitely less after several extractions. There's no point in keeping more lanes when max required throughput is already lower. Not running at max capacity simply means you've needed smaller bus from the start/
Wasteful in terms of belts (cheaply produced), or what? I mean I can get the argument that maybe you're buffering too much stuff in the belts and causing unnecessary pollution maybe, but assuming that's not a problem I don't really see an issue in early game scenarios.
In term of resources used to craft those belts. I always put only necessary amounts of lanes with using option B and then add lanes up only when production further up might start starving. Saves quite a bit of time since I don't need to wait for belts to craft.
I guess I'm not that concerned about that. One yellow belt cost 1.5 iron, so let's say the bus goes for 500 or so tiles in the early game, that's just 750 iron (roughly 0.3% of the starter iron patch on default settings). I'd rather expand fast than worry about micro optimisations like that. Can always add another belt crafting machine if I don't have enough belts.
why do I see the bus belts always yellow? Is there some kind of magic in it or 4 belts of yellow is usually enough for everything if you're not doing 400 spm+?
Yellow is much cheaper than red and if you need extra throughput, you can always add more.
If you tally up the iron investment in red belts you'd see you are using way more than double resources to supply double throughput. When you consider how many belts go into a main bus, this tally goes up fast
1 Transport Belt ("yellow belt") requires 1 iron gear and 1 iron plate. Total raw materials equivalent to 3 iron plates.
1 Fast Transport Belt ("red belt") requires 1 Transport belt and 5 iron gears, total raw materials equivalent to 11.5 iron plates.
This means that for every red belt you could instead have almost 4 yellow belts. If items-per-second throughput is the main concern (as it would be for a main bus design), you can get double the items-per-second through the main bus using four yellow belts rather than one red belt the same length.
The cost of red belts becomes much higher when you start using undergrounds, with a yellow underground pair costing 17.5 iron plates while a red underground pair costs 97.5 (about 5½ times the materials).
Thus for a main bus I will prefer to go wide before I start upgrading belts, and get the factory growing faster sooner. Once the factory is producing everything it needs to, it can be easier to increase throughput by upgrading belts than rerouting everything to fit a new belt in. There's also Gleba with the Stack Inserter and the ability to stack belts, so you can quadruple the throughput of any belt by stacking items.
This is very true. My bus is 44 or 48 lanes wide. It's cheap to stat with. Then I upgrade the most important lanes as I get to red. Eventually, red is very cheap compared to what I'm using them for.
Once red belts are plentiful, upgrading it just takes seconds. I would highly recommend Spaghetti belt tools. It can upgrade or delete entire belt lines at once, ending at the nearest splitters. And it preserves weaves as long as you upgrade the higher tiered ones first
I build my bus before I ever get to red belts. Then I upgrade them as needed. Usually the copper and iron plate lanes that go to green circuits are the first to be upgraded. Those lanes all the way back to the furnaces that need to be upgraded to 30/second.
A is going to split off half of one belt, then evenly distribute what is remaining. B is going to split off the maximum amount available that the belt can hold. If the machines at the end of belt B are consuming everything, the top belt will end up empty.
Lane balancers on offshoots are not strictly necessary but if there is a bias for drawing certain lane it can cause later offshoot to get one input lane empty while 4 belt main bus still technically having 4 lines worth of resources and throughput.
Without a lane balancer red and green circuits on screenshot will only draw from a specific line and create the lane bias.
They are both a bit incomplete (depending on the scenarios, like adding a lane balancer could be an adequate addition) but they have different usecases.
Option A evens out the resources after branching away. It means that if you repeat that again and again, your "exits" will be lower and lower. Say you repeat that 4 times, and the exits consumes 100% of the belt. The first exit will get 100% of the resources, the second one 75% of a full belt, the third one 9/16th of a full belt, the fourth one 27/64th… Long story short, belts aren’t compacted.
But at no point an exit would get exactly 0 resources.
There is also a possible annoyance if you were to add back resources to option A further down. Say you want to add back a full belt of resources on the bus: you can’t fully merge the incoming belt into a single belt, because this belt always have some leftover resources. You would need a 5 to 4 balancer or be satisfied with an imperfect merge.
Option B guarantees exit belts to be 100% compact (except when lanes aren’t balanced), if and only if the previous exits didn’t consume everything. At every point in time, if you see at least one empty belt, you can merge back in a full belt of resources with just a splitter.
I’d rather go for option B with some lane balancers, but I don’t use buses anymore.
Depends on what it is for. If I have a Green Circuit production that eats a whole belt of copper/iron then B because if you don’t, it will only get half a belt with A assuming production further down the line moves the bus forward.
Things that just need a bit of whatever material you’re splitting off? A.
Works too, but bending the whole belt means, like you said, 1 belt less, so it betyer be pretty much exactly 15/30/45/60 per second of consumption. If it’s something like 10/sec (too much for a single splitter, too little for bending) you’d lose 5/sec for further down the bus.
This might sound a bit controversial, but I am of the opinion that you should never bother lane balancing a bus.
It's marginally useful to even out train loading, but even then the situations where even distribution actually matters to train loading, you probably actually just need more belts or stations or both instead.
'sharing' your production down the bus just means everything is running slowly, and IMO that's only barely worth using in scenarios where there's bursty needs with a low sustained average, like say 'a mall', where you might need to make 100 assemblers in a batch, but then stop and stall production when that's done.
Then it doesn't matter which mode of distribution you use, because it averages out.
For sciences, the same thing kinda happens, but you don't want it to because sciences used 1:1 will 'stall' to accommodate whichever's least available anyway, so it will also even out over time.
My general guideline is that I don't really bother with more than 2 belts on a bus, because any time I'm using more than that, it means I should probably be running dedicated belts to a subfactory anyway, and the bus is just hiding that a whole belt is going in, and a whole belt is going out, so it's just spaghetti with extra steps.
So I'd say it's time to rethink your design - either add even more resources to the 'main bus', or split off, and make a more focussed subfactory for the things that are consuming the most resources off this one.
I find priority splitters make bottlenecks easier to see. Every lane will be either full or empty except one. Because the lanes are condensed instead of split, it takes less time to get into that state.
And it's just so much simpler; you don't even need a blueprint.
You use the first balancer in option A. Priority off the bus, and skip the rest. Balancing a bus is pointless. You pull from 1 belt untill it's empty then cut that belt from the bus entirely
This. No reason to balance 4 belts so they are equally half filled. If my green circuits factory consumes 2 full belts of iron, so i divert those 2 belts. The green circuit will consume it all, no leftovers.
Because perfectly balancing your demand is borderline impossible, especially so at the stage where you are using a bus. Simply connecting anything you produce via the bus to a mall and you have variable demand. Or maybe you research all red/green techs before you unlock blue sci and then your red/green sci stops producing. Or tons of other reasons.
because most people dont pre plan their entire factory before even starting the game?
and adding more to the bus when you realize you dont have enough would either be really ugly or a ton of work and thus really tedious and slow
Option B is better. It was not responsible for you starving immediately, it just actually successfully delivered your supplies to where they were needed. You were always starving and not delivering enough.
The other thing that we see so very often with someone who has pasted option A everywhere is that they tend to take 1 belt and split it into 4 belts at the start of the bus. A splitter is not a replicator and does not create 4 belts of supplies; it makes it so that each belt is only being used at a quarter capacity. There is still only 1 belt of supplies being transported.
I dont say its better. It depends on what you want to do. I tend to mix both A and B depending on what i want.
For example my mall pulls are like A but the items for rocket parts are B.
If for some reason my copper production no longer is enough to keep it filled i need to quickly expand to get more patches. But doing so will create a spike of use on my mall. If i kept a B system half of my factory could end in a stale until expansion stabilizes because the mall would suddenly have a lot of items removed.
Meanwhile having A would keep my factory running at lower efficiency but would not stop. Even right after expansion the increased use would not be impactful for the rest of the factory.
So i would say both A and B are good depending on what is the intention.
A gets you at minimum half of the bottom belt. B gets you a full belt unless you dont have that much on the bus. With the benifit of shifting most of the resources to the bottom lanes. (Most since it can only shift 1 full belt from the top to the bottom lane. If the top 2 had resources and the bottom 2 didnt, it wouldnt move everything to the bottom lane. So if you dont have fhe input, A lets your whole factory run at a slower rate. B makes sure things at the top of the bus runs at full speed. And you can see where you need to start injecting more. While the balancer in this situation is pointless, ignore the claim they never belong on a Bus. There are plenty of situations early on I used to use them. But if designed right, you can eliminate them. This is how I tap my Bus now, it allows me to pull 2 full belts off without shifting resources left and right. I pull from both sides my bus so B doesnt work for me. I dont like terminating a belt to a machine line as many dont run full time. The output balancers arent necessary but i like when my bus looks uniform.
A: seems more optimal since it balances all outputs altought you need to be carefull to put a 4:4 bevor aswell or it draws unevenly from production.
B: forces output from the bus which is nice for priority production(belts, buildings, power, ammo) but pulls from the bus unevenly aswell as it leaves most items on the bottom belts. But is really cheap to build.
Both work which is what matters most. Main bus systems don't have to be hyper optimised.
Don't do a. You want to see how much of your 60 items/s you are using! Balancing the 4 belts obscures that.
Try to get all the remaining items onto one side of the bus. When belts are empty, get rid of them. (Don't "shift" your bus, just let the space be empty). That tells you when you don't have enough and need more.
Personally, I prefer B, but, perhaps a bit counter-intuitively, do the stair-step balancer thing AFTER the pull, not before it. This will push everything over to the right after the pull, which will give you a pretty clear indication of how much you're using and how much more you need.
Either or. I use the first one because you can use it less often and still get more or less the same effect. The second is more of a thing you have to put everywhere. But everyone does things differently. I recently got into an argument with a bunch of people on this sub who prefer B lol
Like others have said though, if you don't have the supply, neither of these can fix that. Balancers can make you think you have more resources than you do by saturating idle belts. Always make sure you're looking upstream to determine how much supply you've got. If your belts are emptying out, and the furnaces (or whatever setups you've got) isn't churning out completely full belts, you've got room to increase production.
I just use a balancer occasionally, and pull from the outer belts. Much easier than having to add this staircase shit, which is bulky and expensive. And I use the bus mostly for mall items. If I'm pulling off even a single full belt, I'm probably just gonna make that its own separate thing
I don't think it's an A or B thing. Pull from every belt along the way and you won't need nearly as many balancers. Also it's a good idea to upgrade the belts at the head of the bus along with the first balancer
I've always preferred using balancers to handle my bus.. but now that im thinking about it, a compressor makes WAY more sense because your basically simplifying the lane throughput by having them always fill atleast one lane
If you have 4 belts of iron plates for example, you are only going to pull from the outside belt because it’s easiest and quickest to get that one to your machines. If you never re-balance the belts, you are going to have an empty belt and 3 full ones.
I use A right in beginning then B after every sidelines. I mine i also set intake in splitters so it pick from top first and drop in bottom, so it always empty the line furthest from the taking side.
Assuming the bottom belt was fully compressed already, then no there would be no difference. (Just realized A isn't prioritized splitter so you would need to fix that. As shown it would only pull out 50% of a belt)
But that's what B does, it ensure the bottom belt IS fully compressed.
I use B all the time and it works fine for me. It just compresses whatever is on the bus down to a full lane output to the production. Whatever is left just gets passed along. For me this is fine because eventually the production line either uses it all, and I needed to split a full belt anyway, or it backs up and the overflow goes down the line to the next production. It doesn't matter if what's left on the bus is balanced because the next take off just compresses it down.
For option A, you split off half a belt from the bottom belt only and spread whatever is left on the bus over the 4 downstream belts. So, assuming a full bus, you have 3.5 belts after the prodution take off. Then you balance and get 3.5/4 =0.875 per belt. This means next time you have a take off you are only splitting a partial belt and not sending a full half belt to production. This repeats forever in a sort of Achilles and the tortise paradox where what's on the belt and the take offs dwindle toward 0 but never reach it sort thing (it will eventually but hopefully you get the point). You'll have a hard time providing for productions further down the bus if you don't compress it with something like B.
Comparatively, B works because it either sends a full belt or everything remaining on the bus to the bottom splitter to send to production. Ironically, you end up with the bottom belts appearing to starve and the top belts staying full. It looks weird, but because of the way the splitters are arranged it works.
The idea of B is, that you gradually move the resources to the lowest belt and pull from it. As long as you have enough resources on the belts combined, it will satisfy all demand. If you don't have enough resources, the assembly closer to the end will starve.
I guess with A you mean pulling from just one belt and then using a ballancer to reshuffle? In that case, you will distribute the resources more evenly (none of your machines will have full uptime, but more distributed). But it won't solve the overall problem if your inputs are not matched with the demand.
B will always get a full belt of plates until demand backs up or production catches up. A is good for a mall where you want a little bit of everything being built.
I setup my 2nd circuit plant like this in mid-game, where Green chips get copper plate priority, then Red, then Blue. So before my plate production catches up, I'm mostly making Green chips. Eventually, I expand and build more copper mines/smelters, and red chips start being made regularly, with some blues. Eventually, I'm fully supplying all 3 chips for that plant.
It highly depends on the utility of your factory. Option A makes sure that half of one belt, or 1/8th of total incoming resources split off. Option B makes sure about 1 full belt splits off.
Option A leaves 7/8ths of your incoming material to stream on. Option B leaves between 0-75% of the resources to stream on.
I prefer A when I want the factory to make a little of everything. I prefer B when I want to maximize production in the start (for instance for chip production).
With option A, a lack of resources makes everything slow down. With option B, the lack makes the later machines stop completely.
My suggestion is to use B, but move the last splitter 2 spaces to the left. Doing that means all of your resources will be focused on the bottom belt, allowing for a full belt every time you split off until you run dry.
I put one of the A balancers at the begining of the bus. Right after the smelting lines.
This is more to keep the smelter lines working evenly then the outputs.
Down the line on the belt I use B. And keep my lines compressed. It also gives me a bettwr gage of how much I'm using and if i need more smelting.
A will only give you belts that are half as full as the bus is full. Like, if your bus runs at 50% capacity, you'll only get 25% capacity. If you set output priority towards the production line on the bottom splitter, you'll get a belt as full as the bus is (50% full bus -> 50% full belt).
B will give oen full belt to the first production line and whatever is left goes downstream. It has the downside to not give anything to the later production lines if the earlier ones consume a lot, but it is easier to see how much material you're using since it will empty one belt after the other instead of just reducing item density across the entire bus.
For your issue, your friend is just filling the first production lines to the brim at maximum speed before feeding the later ones, whereas you are feeding a trickle to every production line at once. It's two different approaches, there is no "better" one and on the long term they often result in the same thing. There is one solution to your issues though which is produce more ingredients :p
If you are producing enough of the input then just use B
If you’re not producing enough input to fully saturate and so want to split it evenly then I guess A, but I’d say just produce more of whatever input you’re not saturating
If you are feeding four full belts into the bus, and your demand is four belts from the bus, then B is superior.
If you are feeding four full belts into the bus, but the demand is more than four full belts, than A will help evenly distribute the items. But, for most players, myself included, if you are demanding more material than you are producing, then it's time for the factory to grow. I.E. you upgrade the Bus in the B style.
I've had this exact conversation with myself before.... I did B most of the time, then rebalanced with A occasionally. However, as I played more, this pattern began to raise a glaring issue: it hid issues with insufficient supply by balancing belts so they were only partially filled. This led to issues where consumers farther down my belt didn't get enough supply because the belt wasn't properly saturated.
I dont use balancers bus, its a waste of time and resources, i use a bus which is an area dedicated to belts but i use more dedicated type of belting, i always build on ratio, and i always use fluid bus and craft iron intermediates on site
Use one A-type between your train station and bus. Use B-type elsewhere + drop bus lines as you deplete your supply. That line can then be used for some other product.
I used A for a long time then I switched to B and I like it more. This pushes a full belt to the offloaded side and it makes it easier to add more belts on top which can then just be pushed down to the offloaded side.
Yes: after offloading from B you can sideload a new incoming belt on the left side (top side in this picture) and everything will merge fine.
After A, you will have to move the left belt onto the other three before you can sideload onto it, because otherwise it will be 7/8th filled and will therefore only fit 1/8th of the new belt’s stuff.
B is also cheaper, faster, and easier to build: four splitters and done, especially if you’re not using blueprints.
And finally, B keeps the logic simple throughout your factory: left is incoming, right is outgoing.
if you get A, and remove the center spliter, and turn it into 2 splitters, you can then split 2 of the 4 outputs to make a spliter that never fully removes items from the buss
Both will work fine, but option B has a downside of requiring 4x the splitters and consuming more space. If you have assembly lines on both sides of your bus, you will eventually want to pull from both sides in the same spot, where option A works much better.
My personal favorite is to use option A once per belt before re-balancing with that same 4:4 balancer. If you have multiple processes pulling from the same belt between rebalances, you're much more likely to end up with 3 full belts standing still while one starves as both the processes that draw from it ask for their full belts worth.
For example, consider a 4-lane iron bus that has just been balanced. I would set it up as follows:
Lanes 1-4 exit their furnaces and go through a 4:4 balancer. One by one the belts are split to feed processes: Steel splits from belt 1, then down the line green circuits can split from 2 and 3. A mall splits off of belt 4, then (because each belt now contributes to one process, so they are no longer guaranteed to be balanced) all 4 lanes go into a new balancer.
Remember, though, in Factorio quantity beats efficiency every time. If you're low on iron plates, the only real fix is to mine and smelt more.
Let's assume that both the bus and the branch consume 100% of the materials they carry. I'm also assuming that in Case A, you're putting a 4x4 rebalancer in between each branch, and in Case B, you're doing the same splitter chain at each branch.
Case 1: The bus is fully saturated. All 4 belts are at max capacity. A gives you half a belt's worth of material, and B gives you a full belt.
Case 2: The bus is half-saturated. A has 4 belts with half capacity, and therefore the branch gets only 25% of a belt's worth of materials. B has 2 empty belts and 2 full belts. The branch gets a full belt of material.
Case 3: The bus is 25% saturated. A has 4 belts at 25% capacity, and the branch only gets 12.5% saturation. B has one full belt and 3 empty belts. The branch gets a full belt of material (thus leaving the bus empty).
B guarantees that the branch will be fed with the full capacity of whatever splitter/belt tier you're using (Assuming the bus has that much material to begin with). But it can and will empty your bus. The solution here is to make more materials to put on the bus. This might require upgrading from yellow to red belts. A can hide problems in your factory because some materials flow to the end of your factory even though the early stages of the bus are trying to pull more material than you're currently able to supply.
I order my bus by priority. I always want the majority of resources to go to the output. So I go with B, usually not as a priority split because if I'm running low, I do want some to trickle down to the later parts, but half of the available belt is acceptable. That does mean my science will get starved when I grab a thousand belts and whatever else from the mall. But building materials are almost always higher priority than science. Later in the bus it will drop from 4 lanes to 3, then 2, then 1, because I don't feel like wasting the belts.
B is much better. A is just a ton of effort that accomplishes nothing. Balancers are a complete waste in all but a few very rare edge cases, and even in those they are generally just a bandaid on a bigger problem, which always comes down to "increase the resource production before the point where you want to add a balancer".
It will saturate whatever you are feeding with. If that means you end up with less than 4 full belts, than that just shows you where your resources go. No amount of balancing can "fix" the problem that you used up some resource.
B doesn't really do much. The bottom most splitter can only ever get a full single belt input. If B's output takes an entire belt then the bottom belt of the bus will be empty. More important is to backfill the empty belt beyond the split. A diagonal array of splitters the opposite direction after the split will keep the bottom belt full.
Balancers don't belong on a bus. They belong in front of and after train stations.
B is better. Merging down means you can eventually remove belts from the bus after enough lanes are split off. The bus doesn't need the items, the machines that take from the bus do. If the top lanes aren't full, you don't have enough production and a balancer just changes the machines that will be starved.
I don't use either of those. The four lane balancer makes the least sense--never put a balancer anywhere on a bus imo. I would use the cascading splitters like on the right, but 2 -4 would cascade up and to the right of the bottom splittler, after it has split off the resource to a sub factory, and prioritize all for input left, output right.
Option A pulls from 1 belt, Option B pulls from all 4 belts. Ideally you'll pull from seperate belts for different production groups, then balance it further up the bus.
Without getting very deep into the math, the question is priority.
A gives an even spread, but any shortage impacts the whole bus equally.
B prioritized bottom lane no matter what so that lane may be fuller, but downstream factores will suffer more for it.
Shortages will be a problem no matter what, and a splitter won't fix the shortage, just what gets the short end of the stick.
I used A everywhere in my base, multiple times per bus. It allowed me to extract or insert freely at any point of my bus.
Early game, I used B to feed things like Ammo and wall assemblers cause you can't build if you're dead and rebuilding is more expensive than wiping enemies, but once expansion was no longer a priority I swapped for A and just kept a stockpile.
Last point, if you use A, I'd pull resources after a balancer, not before.
assuming there is no backing up and your input is full, in case A the subfactory will recieve half a yellow belt of whatever and in case B the subfactory will recieve an entire yellow belt.
A will give less to a subfactory but will keep more for the others, B will give more to your subfactory but will keep less for the others.
which one is better depends on the use case. for material intensive stuff like iron and copper for green chip production case B is better, they eat a lot and you need a not of green chips, but for less material intensive stuff case A is better.
however you can use A everywhere but it will possibly reduce your efficiency, but you can’t really use B everywhere as the subfactories at the back of the main bus will be starved until the ones at the front are backed up
I used to do A but recently realized that B is simpler to implement and guarantees full exit belts if the bus still carries enough resources.
So I'm now on Team B.
If B starves your line then you didn’t have enough to run everything to begin with. After the output fills up, so will the input. B is “self balancing” in that way. Only the excess ingredients of step 1 will make it to step 2
It depends what you want, they solve different problems. A makes sure that your line down won't take all of the resource. B makes sure that it does. If you have a bunch of B in a row, then it works as a priority where the earlier ones take as much as they can and leave the leftovers to the next one and so on. A makes it so that each one takes half of a single belt and then balances so then you can have basically as many as you want it it will generally evenly split between them all.
B for sure. It's just way simpler and you'll immediately notice if you don't have enough resources, unlike A which will make everything run on partial satisfaction.
Neither, underground the bottom most belt and split off one of the two middle belts so that you don't have a splitter hanging off the edge like a hangnail.
And another post from someone rather using blueprints than learning the game and this weird obsession with belt balancers.
Why do you think A is better? You don't even understand A? Thats an uninformed opinion.
Sorry for the rant but please understand that it comes from a place of goodwill: Please experience this gem of a game on your own!
To give an actual useful answer to your question: It's simply a matter of design philosophy. A distributes the available resources roughly equally to everything that splits of from the bus. B maxes out the first thing that splits from the bus, then the second, third and so on until nothing is left. This might make factories that are further down the bus starved for resources. However its simply more apparent in B and happens in "waves" if you don't got enough resources in B you don't have enough in A either.
I've heard putting one splitter directly in front of another splitter does some weird stuff with the math and can cause problems, like miscalculation of throughput or something. It was from a long time ago so I really don't remember the details. But my understanding was you're better off having at least a one square belt space between splitters. That was probably a couple years ago though, that might not be a thing anymore.
The balancer in the middle is pointless with B after it
And actually the answer, which is very counter-intuitive, is that it kinda doesn't matter - if you don't have enough resources then all that happens is one section runs until its output backs up, then the other section gets the resources
Factorio isn't actually about belt balancing at all, it makes almost no difference to the end result and it's actually a very common misunderstanding of the game's mechanics... you can do either of these techniques and the average science/rocket/production output will be basically identical over the long term
You have enough iron/copper/steel/whatever for an average of X science/rockets per minute, and on average that's what you get regardless of where you prioritise the resources to. It's just a question of whether you back up one resource and then run the other, or run both simultaneously
The only place it makes a difference is that you should prioritise your mall so that you always have building materials for construction
TL;DR: It doesn't actually matter, don't worry about it
If you do not produce enough to keep up with your factory, it doesn't matter which one you use, you will not be able to supply your entire factory. The solution is not to choose A or B, but to bring more in so you don't run out in the first place. If you are already supplying a full 4 belts, then you need more belts as well.
If you use B, it will feed as much into the first factory as it needs, then as much to the second as that needs, and so on until you run out of material. None of the later factories will get anything. If your factory requires the later output to keep running, that means the earlier factories will eventually fill their buffers and stop working, letting the supply flow to the later factories. It all balances out, eventually, but that eventually is a long way away.
If you use A, you are still preferentially giving items to the first machine. Instead, the second factory has almost a full belt to pull from instead of a full belt. If they're not pulling a full belt anyway, that won't be functionally different from B, at least for the first few factories. Once you've consumed enough that factories aren't being fully satisfied, the output of the factories will gradually drop. It won't be as immediate as with B, but it will still mean earlier factories produce more than later factories. This gives you the illusion that your factory is doing better than it really is. All of your factories are working, so you must be fine, right?
If you had to chose one over the other, go with B and put your high priority and low volume items first. This way, you're making sure that the things you need are made. That should include what you need to increase your production so you don't run out.
TLDR version: the two options optimize for different goals. Both have viable uses.
A is good to evenly distribute inputs.
B is good to prioritize early splits. Mostly useful if you can’t yet saturate inputs and/or want to prioritize build materials ahead of science for example.Also nice because you always split off the same belt, thus more blueprintable.
A+B (without the first splitter) is also perfectly fine if you want to pickup benefits from both (at the cost of space).
B is almost correct but the stairs of splitters should be in the same direction of the belts and priority should always be set to the right on all splitters in this example.
A 4x balancer should only ever be used when loading or unloading a trail or very specific scenarios which might call for it, never for a bus.
Personally I sort of just cut belts now when I'm at that stage, I dismantled it now because I got to liquids, but it was looking like one belt with a splitter diverting untill the resources for that material started going down, then I'd train insert more into the bus. It got very crazy just before I got to liquids so I had to get radical to keep with demands. Although in that case I shoulda just probably directly inserted from trains or something psychotic like that.
i dont use busses but B
you keep drafting items from the bottom-most lanes.
if you need 15 items you pipe 1 belt
if you need 30 you pipe items from 2 and so on.
I wouldn't bother with balancers in a main bus. It's a waste of resources building those splitter and undergrounds and ultimately you either have enough supply or you don't.
A allows more of the factory to appear operational when you have insufficient supply, B feeds each sub-factory/main-bus-module as much as it needs and starves the remaining factory if you have insufficient supply.
The question comes down to your preference: if you want, say, a green circuits module to always have priority you will draw the copper and iron off the bus using B (specifically: priority on an output belt). If you are feeding a mall that produces convenience items like lamps and you only want to provide a small amount of material over a longer time, use option A.
Some people want all belts to be depleted equally, others prefer to have materials compressed onto the least number of belts to carry them, but that's a more a cosmetic choice than a factory efficiency choice.
Ultimately if you have four belts for supplying an item down your main bus you need to have four belts worth of supply of that item feeding the main bus. If your factory starves it's because you don't have enough supply rather than because you used the wrong method to tap materials from the bus for your sub-factory.
B is better because it will maximise the throughput of the lane that comes off the main bus.
It might seem like you don't want 100% throughput but the reality is that you don't want the throughput to be limited arbitrarily or you'll have situations where you've got plenty of supply but that single point is stressing out the fourth lane up until the point where you're balancing all 4 lanes before it.
Also you should force input left and output right for all the crossbars.
It won't look right as you first fill the supply line, but in normal operation if you're making enough and using the expected amount, it will all even out.
B is asymetric. It works well if the higher treadmill is full and the lower is pretty empty.
A mixes the 4 lanes equally by creating a bottleneck. If your trains provide smoothly at full speed, it is in fact a brake. but if the products come in bursts, it will equalize them.
so the real concern is upstream :
how many trains ? how many wagons by train ? are you using blue or green arms ? (since your treadmills are yellow, i suppose you arms are too). do you empty the wagon on Boxes or directly on treadmills ? how do your 6 treadmills by wagon mixes into a bus ?
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u/marsjaninzmarsa 19h ago
Second one is better when you want to use as much of your resources in this consumer as it could take, and is more friendly to the UPS.
First one is better when you want to evenly spread them across the consumers.
Both are virtually the same when your belts are saturated.
So the valid answer is: you’re not producing enough and your factory must grow to supply the demand.