Factorio: How to Build a Main Bus

Factorio: How to Build a Main Bus

- in Factorio Guides


Factorio is an awesome game in which you are allowed to build up your factory empire. However, you can get some troubles if you don’t know how to manage everything. Especially, we will introduce to you an important problem relating to the Main Bus. A Main Bus is the factory design which is widely used because it is flexible and easy to use. A good Main Bus will help you construct a neat and effective factory. Then, it can produce and provide all of the products that you want.

At the beginning

In the start of Factorio game, you could see many conveyor belts. Aside from that, you would recognize that they are pretty good. They could help you to solve quests and reach the best end.


In the initial phase, you will use yourself to transport and move everything between chests. Next, you have to carry out an electric setup, achieve the electric mining drills to supply lines of furnaces. These first lines are the debut the new Main Bus.

When you use conveyor belts for the first time, you’d better boot a Main Bus. If your set up gets any delay, it will cause wasting time and postpone every effort from creating temporary lines.



If you’d like to play Factorio game better, you should make a detailed plan. This plan will be very useful for you when you are in the earliest stages. And your plan needs to concentrate on the place where your main bus will arrive. You may want to go in a straight line horizontally or vertically. However, this main bus can snake around lakes. Don’t take a large space by making corners with the large width of the belt!

Take a look at the own map, select a wide open location with expandability in at least one direction away from ores or ore processing facilities.

Factorio: How to Build a Main Bus


The yellow arrows will show you the possible starting locations and directions for the Main Bus.


These materials are very useful to design the main bus.

  • Iron Plates x2 (recommend x4)
  • Copper Plates x2 (recommend x4)
  • Steel Plates x1 (recommend x2)
  • Green Circuits x2 (recommend x4)
  • Red Circuits (Advanced Circuits) x1 (recommend x2)
  • Blue Circuits (Processing Units) x1
  • Plastic x1 (recommend x2)
  • Batteries x1
  • Lubricant (via pipe)
  • Sulfuric Acid (via pipe)

“x” numbers mean the number of belts for a regular sized factory. The recommended numbers are reserved for a fairly large factory which requires good throughput for multiple rocket launching. You will be able to learn more about using the recommended numbers in the rest of this guide.

Factorio: How to Build a Main Bus


The rainbow of belts will give you the great throughput for your factory.

Belt Structure

There are a few different structures in Factorio game that you can pick out for the main bus design. Some will place all lanes together. But, you can build up a structure of 4 belts, 2 spaces, 4 belts, 2 spaces, etc. with the piped products on one side. This new structure lets you split from the side of one belt group easily. It will leave the space for you to put down an underground belt.




You should leave the space between belts to allow undergrounds to pass through. Add pipes for the liquid component of the Bus.

You don’t have to create all-the-belts initially. But, you can make a placeholder with a single square of belts per line. From that, you will know the distance to place assemblers from the line.

You are possible to mark the lane with a piece of material. Hold this piece in hands and press Z to drop it. Try to aim for the belt!

Markers on the belts are effective to help you remember the place you go.


Markers on the belts are effective to help you remember the place you go.

Feeding the Bus

Belt Balancers

Before you put it on the line, you should keep a belt balanced. You can use any item below before they get to the Main Bus.

Factorio: How to Build a Main Bus


Corner balancer. Colors of belts are different.

Factorio: How to Build a Main Bus


Straight/in-line balancer

Factorio: How to Build a Main Bus

Balance steel before it is mixed and moved to the Main Bus.

Lane Balancers

On the Main Bus, you can use a regular splitter to balance products if you own two lanes. Though, if you get four or more lanes, you can use a better structure to split items between belts.

Factorio: How to Build a Main Bus

Build diagram of a four- lane splitter.

Markers on the belts are effective to help you remember the place you go.


4-lane splitters in reality

Explore more balancers on this Reddit Post.

There are plenty of lanes. But, they are not enough for production.

You will feed the bus from furnaces making iron and copper plates. Make sure you must use splitters to divide some of each to all expected belts. For example, if you have only one belt of copper plates, use a splitter to distribute them over allocated 4 lanes. This allows you to apply both sides of a 4-wide lane of products to do that. Besides, you are able to add in the new lanes of plates for throughput without effort when you can build them.

Introducing Intermediate Products

Adding intermediate products in Factorio game is quite simple once you leave enough space for them. At the end of each assembly line, you have to balance the belts before you place them on the line.

Factorio: How to Build a Main Bus


It’s easy to add in green circuits when you have a plan! Split one belt across 4 belts allocated until you can build more production.

You can add products on mid-line, even when their contents move in the opposite direction.

Adding Liquids

Most of the liquids can surround the oil processing area.

  • Lubricant: is used to make Electric Engines & Express (blue) level belts, splitters, and undergrounds.
  • Sulfuric Acid: is used for batteries and processing units (blue circuits).

Pulling from the Bus

You should place assembly lines at the position where they will run perpendicular to the Main Bus. When you do this, expandability of systems can pull from the Bus.

Pulling from the Bus

The bus can run North/South and assembly lines come off and expand to the East and West.

Different products can share similar intermediate product needs. They can split input lines. Don’t put too many items on the same line because it can cause a shortage of materials for others down the line!

Pulling from the Bus

Pulls from the Main Bus service a lot of individual products when they share the same inputs.

Full Lane Split Off

To transport a single material down the line, you need to put a splitter on the line and use undergrounds to bring it to the area that you aim.

Factorio: How to Build a Main Bus

In the first stage of a full belt split off, you’d better balance the Main Bus lines.

In case you are pulling from a mid-line in the bus, you should pay attention to using undergrounds to allow the rest of the products on their way.

You can leave at least three tiles of space along the belt side of assembly lines, one for inserters and two for belts.

Two-material Split

Most of your split-offs from the Main Bus of Factorio game are a single belt which transports two lanes of different materials. This is an efficient design that you can offer up to eight different intermediate products with standard inserter setups. You are able to build up a structure like this: two belts feeding into a single lane, forming a T where the belts meet. Each of them can be dropped on to the side when they are placed this way.

The easiest method to get a two-material split off is starting at the position near the assembler, and work backward. Carry your belt to the target lane and split. Create the T-junction before you match it to fill only a single side of the belt!

Work back from the second side of the T-junction to get the second material.


After splitting, you have to balance the belts again to feed more. It is the important step in Factorio game. On a two-belt line, you will use a regular splitter. On a four-belt line, the furthest belt from the split can feed into the edge. Utilize three splitters to deliver resources back to that lane.

Full Lane Split Off

Original Split Off

Factorio: How to Build a Main Bus

Adding in splitters

Factorio: How to Build a Main Bus

The arrows indicate the direction of product movement.

If your lanes are chronically unbalanced, you should consider putting an appropriate 4 lane belt balancer.

Factorio: How to Build a Main Bus

A proper 4 lane belt balancer

Another example of splitting two products off the Main Bus

Factorio: How to Build a Main Bus

Splitting Off

Factorio: How to Build a Main Bus

Adding the replenishment splitters

Avoid using Underground Splits!

If you select the “quick & dirty” way of using an underground belt to draw from the split, you must know that you will only pull from one-half of the belt. And this will cause a serious problem for the balance.

Sometimes Undergrounds are useful.

When you’d like to divide two products from a belt and want full throughput in an easy way, you can pick an underground belt.

Splitting 1 lane from the belt:

Factorio: How to Build a Main Bus

Separating both lanes:

Factorio: How to Build a Main Bus

Example Assembly Lines

These are some examples revolved around the assembly lines in Factorio game.

Red Science

Red Science needs Gears & Copper to craft.

  • Place Assemblers: 1crafting Iron Gear Wheels and 6-8 making Red Science.
  • Set two rows of belts along the assemblers. Put another along the output side.
  • Arrange 2 fast inserters in, and 1 fast inserter which going out of the Gear Wheel assembler. And, put a regular inserter and a long armed inserter so that you can feed each Science assembler.
  • For the belt furthest from the assembler, you will have to split off copper plates.
  • For the belt near the assembler, you can split off half a lane of iron plates. Ensure that the empty side is across from the inserter!

Green Science

Green Science requires belts and inserters to craft.

  • Place Assemblers: 1 crafting Iron Gear Wheels, 1 each for belts and assemblers, and 8-10 for Green Science. Try to put them one tile which is away from the Red Science output belt! Then, this Green Science will distribute the other side.
  • Find and put 2 rows of belts along the gear, inserter, and belt assemblers. Next, you will place the snaking belt leading to the Green Science assemblers as each screenshot below.
  • Then, you can place inserters as the following screenshot. Inserters need long arms.
  • For the belt furthest from the assembler, you can divide green circuits.
  • For the belt close to the assembler, you will split half a lane of iron plates.

Belt Array

To own a fast and helpful belt array, you need to build:

  • Identify the place for assemblers and put them in a grid-like pattern, add belts, inserters, and power poles after that.
  • Chests can move items along. They can supply the great place for pickup. These start out as iron chests, upgrade to Passive Providers and to Requesters.
  • Split iron into two places for throughput, and a half-belt of green circuits. If you don’t possess any red circuit, you can make a plan from now on.


Divide a full belt of red circuits to get close to the assemblers.

Green & blue circuits will share a line going in.

Maintaining the Bus

  • Attempt to re-balance belts after they are split.
  • Upgrade belts when you need more throughputs.
  • To upgrade belts, you should run along the line, hold down the mouse button to put belts on top of existing ones. It’s possible to replace splitters and undergrounds by placing upgrades on top of the old!
  • When you have robots, you can extend the bus with the design.
  • Fill the belts with Copper & Iron Plate, Steel, Green Circuits, so on.
  • Place Concrete or Stone Brick under some lanes of your bus and in one of the spaces between lanes
  • After you realize that you need an extra component which is used for items like stone, stone bricks, or coal, you can run a line to the side of the main bus, finish it at the assemblers, or carry materials in via robots & requester chests.

Science and Bus

Science pack production can pull off of the main bus to get an expandable system.

Moving off the Bus

You can move off the bus when your need for materials becomes greater. Some players build assemblies off to the side or carry products by train when there is not any space near the beginnings of their factory.

Screenshot Examples

Here are some collected examples of the Main Bus system used in Factorio game.

Screenshot Examples

One of the first factories using a Main Bus system

Screenshot Examples

This is the first Ribbon World. The map was 100 tiles high x infinite wide.

Screenshot Examples

This is the first speed run factory

Factorio: How to Build a Main Bus

Handcrafting Challenge factory

Factorio: How to Build a Main Bus

Another horizontal bus 

Factorio: How to Build a Main Bus

This is the “Crunchy Desert” factory

TipsFactorio: How to Build a Main Bus

Take a look at these tips. They may be very useful for you when playing Factorio game.

  • Copper Cables: They are used in most nothing else. They are not helpful for the belt. 1 copper plate can make 2 copper cables.
  • Gears: 1 gear factory can produce more than enough for an assembly line. While the iron comes on half the assembly line, gears are placed on the other half.
  • Locations, where gears are necessary, are in great quantity. Gears via Main Bus are always lacking.
  • Coal, Stone, Stone Bricks: They are used in very few products. Actually, they aren’t valuable using lanes for on the Main Bus. You can carry them in on the side via conveyor belts or through logistics bots.


These are the additional references for all:

  • The Factorio Game Forums (forums.factorio.com) – The official game forums. It is a good place to look for discussions & mods.
  • Factorio Wiki (wiki.factorio.com) . There are a lot of helpful information here. It is the official game site.
  • Factorio Game Guide (guide.factorio.com).Come here and explore great tutorials, again, an official source.
  • Factorio Cheat Sheets. Every guide to ratios, items/per second, and much more is clear.
  • Factorio Data (factorio.rotol.me). You can find which components go into what and look up ratios for nearly everything in the Factoratio section.
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