Megabus Lane

[terraflare]

Was on megabus lane project (currently learning about it) and so far if anything I'm puzzled.

I'm seeing a lot of people with megabases have like 4 lanes of basic inputs each (4 belts of iron, 4 belts of copper, 4 belts of etc). Let's say a factory line requires one or two belts of a material, how do you assign it? Saw some bases just keeps adding a splitter at the edge of a lane. If this is so, what happens to the 2 middle lanes? (This is considering the material is tossed to the left and right hand of the input if the assembly lines go vertical, or tossed to top and bottom if the assembly line go horizontal).

Is there any drawback from having just 2 belts of supplies each?

[Ingolifs]

After each lane is split, the typical thing to do is add some more belt balancers to redistribute the lost flow from the split off belt.

The reason why this is used in general (as opposed to the spaghetti style where inserters draw directly from a single belt), is because it distributes resources more fairly to different parts of the base. Otherwise when you have a shortage, and something else goes wrong (oh no, biters are attacking your base), you realise that placing the turret and ammo assemblers after the stack of gear assemblers wasn't such a fine idea after all.

[Serenity]

Low volume production is perfectly fine with half a belt split off. Especially when it's not constantly running. But for things that need a huge amount of stuff you need dedicated input lines. For example it's fine to run green circuits off the bus at the beginning. But eventually you'll notice a lack of iron and then copper. So plan ahead and make sure you can eventually dedicate own furnaces to it. Placing it at the beginning of the bus and leaving space in front can make that easy. Then you can have 4 lines of iron to the bus and X lines to the green circuit array.


To replenish material in a depleted lane, quick and dirty you can add a series of cascading splitters to push back materials into the lane you just took it from. Even before the split, so the lane you're drawing from gets more materials.
You can also take from the inner lanes and pass the split off with an underground belt. That's a good idea if you have two assembly lines after another that need the same material. Then the first one won't starve the one after it.
But after a while a proper 4-4 belt balance is needed if you have several assemblies that consistently take a lot of materials. That mixes the belts together and distributes everything evenly.


An easier approach is using a priority splitter now that you can add belts to the circuit network:
https://www.youtube.com/watch?v=PZMUtcztWeE
But that requires only taking from one side of the bus. So you can't have a bus and assembly lines on both sides. But you get a full belt for the assembly line and then the other belts are pushed down
The basics explained (but is flawed as noted in the first video):
https://www.youtube.com/watch?v=_63N3QuPZF0&t=332s

[SyncViews]

Is there any drawback from having just 2 belts of supplies each?

Number of belts really depends on how big your building, and how many intermediate products you assemble ahead of time.

e.g. in all my recent ones, I made gears, and all 3 circuits before the main bus. As a result, the amount of iron plates and copper I need on the bus are far reduced, so for a moderately large base its more like this in terms of actual requirements.
2 steel, 2 iron, 2 copper, 2 gears, 2 green circuit, 2 red circuit, 1 blue circuit.
But in practice id build double that because redesigning later when 2 express belts is not enough is essentially a case of rebuilding half the factory.


As for "fairness" and belt balancers, I normally design to be intentionally unfair. If I have a gun turret game, and I run low on iron ore then fairly distributed that to everything, Ill run out of ammo and die. Building rockets and such I care a lot less for. So important things like ammo production Ill actually have at the start of the bus, and take steel/copper from every belt before merging it. Most of the time those belts just back up to the bus and 90%+ of the resources carry on, but if Im short of steel or copper, having an "unfair" amount go to ammo is better. On a similar note I'll make sure almost all the iron-ore goes to steel before it goes to regular iron plates.

Generally such that science and rockets get the lowest priority (e.g. even belts, assemblers, miners, etc. are more important, because the worst thing to happen is you need to expand, then find your chest of stuff to expand with is empty because science ate it all).

Most of this can be done by feel without much special balancer design. Its only at the very start of the bus that you have near full express belts, and even then, Id never design for N perfectly full ones, if I needed that id sooner build 2N belts so I have expansion capacity.

[terraflare]

Placing it at the beginning of the bus and leaving space in front can make that easy.

Luckily I did that alr, but the location of the green circuit is actually the same with all other "shopping" items, means they draw from the same material belts. Will this affect the balance in the future? I can actually see my belt not going fast enough to feed all the way to the back, instead of splitting the belt into two, I had to dedicate one bus lane to that specific assembly line. Which is exactly how u said this:

To replenish material in a depleted lane, quick and dirty you can add a series of cascading splitters to push back materials into the lane you just took it from.

But after a while a proper 4-4 belt balance is needed if you have several assemblies that consistently take a lot of materials. That mixes the belts together and distributes everything evenly.

I'm not sure I follow this one though.

An easier approach is using a priority splitter now that you can add belts to the circuit network:
https://www.youtube.com/watch?v=PZMUtcztWeE
But that requires only taking from one side of the bus. So you can't have a bus and assembly lines on both sides. But you get a full belt for the assembly line and then the other belts are pushed down

I watched this and was wondering if the boxes after the splitters are mods? I never see that item in vanilla. I did not hear the video though was still at work, I'm gonna get to it after I get home.

[Serenity]

I don't put a balancer after every split off. That would take up way too much space with four belts. As said an quick and easy fix is not always take from the outer belt, but also the inner one now and then:

Splitter

Splitter.jpg (425.97 KiB) Viewed 6246 times

Especially if you have two lines that need lots of iron right after another for example

It's only if things that extreme that I placed a balancer. And that's just by eyeballing that things don't quite flow right. Not out of any desire to make sure that things are perfectly distributed

I watched this and was wondering if the boxes after the splitters are mods? I never see that item in vanilla. I did not hear the video though was still at work, I'm gonna get to it after I get home.

The boxes appear if you attach a circuit wire to a belt. Then you can count the items on the belt and selectively turn it on and off

[Serenity]

Here is what I meant:

Balancer

Balancer.jpg (322.67 KiB) Viewed 6237 times

The blue splitter is for the red circuit which eat a shit ton of greens. The red ones help push over more green circuits (I just haven't upgraded the whole bus yet, so it's all a weird mix of colors). That isn't anywhere near perfect, but it helps.

The big structure below it is a 4 lane belt balancer. It takes all input belts and distributes them equally to all output belts. Belt balancers exist for all kinds of configurations, but 4-4 or 8-8 are probably the two most common ones. As said you don't always need this. You'll want one at the beginning of the bus to distribute everything evenly. This one is only there because red circuits need so many greens. At the moment I only have a single other one for green. And that's far down the bus

Just watch if and how lanes gets depleted. And if some production line further down the bus gets starved because of that. Then you can decide if you need to do something about shuffling around the stuff and how well that needs to happen.

[terraflare]

Here is what I meant:

Balancer

Balancer.jpg

The blue splitter is for the red circuit which eat a shit ton of greens. The red ones help push over more green circuits (I just haven't upgraded the whole bus yet, so it's all a weird mix of colors). That isn't anywhere near perfect, but it helps.

The big structure below it is a 4 lane belt balancer. It takes all input belts and distributes them equally to all output belts. Belt balancers exist for all kinds of configurations, but 4-4 or 8-8 are probably the two most common ones. As said you don't always need this. You'll want one at the beginning of the bus to distribute everything evenly. This one is only there because red circuits need so many greens. At the moment I only have a single other one for green. And that's far down the bus

Just watch if and how lanes gets depleted. And if some production line further down the bus gets starved because of that. Then you can decide if you need to do something about shuffling around the stuff and how well that needs to happen.

NO WAYYYYY WHY DIDNT I THINK OF THAT? Mine is similar but I used 3 splitters in the middle to balance it out, then combine the 2 lanes together joining the outermost lane. Now with this in mind I can better balance the belts. Thanks a ton!

And also the splitter from the inner lane too. My gawd I can understand everything but I didn't even close to coming up with these. Still a lot to learn after all.

Thanks a lot for the tips, will let you know if anything comes up

[AndrewIRL]

Now with this in mind I can better balance the belts.

I used to think this was a good idea but I saw a video where a guy pointed out that his base only pulls from one side (most mainbus designs only pull from one side) so there's no need to balance across the all lanes but rather prefer to always push to the one side. He was injecting new resources from the other side when he could see the outside belt was getting depleted. Easier to notice one completely empty belt rather than 4 belts each 75% full.

Balancers, don't use them on the bus

Steejo.png (852.41 KiB) Viewed 6204 times

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[Engimage]

To make a perfect split out of 4 lane bus you need this one (taken from https://www.reddit.com/r/factorio/comme ... t_methods/)

4 lane splitter

You most likely have 4 belt balancer like on the image in the start of the bus and will have multiples of those 4-splitter combos to make splits to your production lines.
The upside of such splits that it will have all your lanes and splits saturated up until the end if you provide enough input.

[SyncViews]

True, making sure potentially all the input can flow to the end is important, but I still rarely see the need for such fairness or balancing along the bus.

For example if that 1/8 led to ammo, repair packs, or anything else important, id far rather give it a much bigger share if there is too little input to back the belt up. So for 2 belts potentially something simple like this to say take steel to ammo, turrets, etc. production.

belt.png (246.34 KiB) Viewed 6211 times

4 belts and keeping the bus fairly balanced is also possible, and for higher throughput needs making proper use of both sides of the belt, but I still tend to follow the same sort of bias for important stuff.

[Serenity]

I used to think this was a good idea but I saw a video where a guy pointed out that his base only pulls from one side (most mainbus designs only pull from one side) so there's no need to balance across the all lanes but rather prefer to always push to the one side. He was injecting new resources from the other side when he could see the outside belt was getting depleted. Easier to notice one completely empty belt rather than 4 belts each 75% full.

Watch the follow up video though where he shows that at it's not that good and has a better version:

https://youtu.be/PZMUtcztWeE?t=99

The split off has one more splitter and the rest is shufflers across the belts

[AndrewIRL]

Watch the follow up video though where he shows that at it's not that good and has a better version:

https://youtu.be/PZMUtcztWeE?t=99

The split off has one more splitter and the rest is shufflers across the belts

I had not seen that and failed to spot the problem in the original design, thanks for passing this on.