Transport Belt Basics - Factorio-Access/FactorioAccess GitHub Wiki
Transport Belt Basics
Transport belts are machines for automating the transport the items across the land. Each belt is made up of single-tile-sized belt units. A belt unit can face any of the four cardinal directions and it moves items on it towards the direction it faces, with items stopping at the end of the belt if they have nowhere to go. Multiple belt units can get placed end-to-end to create longer belts that can snake around the factory as you please. Weaving multiple long belts around the factory can create messy belt networks affectionately known by the Factorio community as belt spaghetti.
Belts require no power source and they work with constant speed and predictable rules, making them satisfying to work with. If you stick to having only one type of item per belt, then things are pretty simple: The item goes where the belt goes, no questions asked.
Things get more complex when thinking about carrying multiple item types on the same belt, which makes it important to think about the lanes. Even though a belt unit is a single tile wide, it has two lanes on it, with one on the left side and the other on the right with respect to the direction of travel. Items normally stay in their own lanes unless belts are arranged such that the sideload each other, as further explained later.
Belt tiers
Regular (yellow) transport belts are available from the start and they carry 15 items per second. Fast (red) transport belts carry 30, and express (blue) belts carry 45. The higher tiers are significantly more expensive in terms of iron gear wheels. They are also too fast for burner inserters to grab from.
Items on belts
Items on a belt travel in the belt's direction until stopped by the end of the lane or by backed-up items ahead of them, forming queues. A belt unit holds up to four items per lane. A belt with no empty spaces is said to be compressed.
The engineer can pick items directly off a belt by holding F, or place items onto a belt by holding Z.
Inserter and drill interactions
Inserters always place onto the farther belt lane from them, even if the nearer lane is empty. They pick up from both lanes but prefer the nearer one. Mining drills always output onto the nearer lane.
Sideloading and merging junctions
When a belt segment ends at the side of another belt's middle section rather than its end, it sideloads onto it. Both lanes of the pouring belt empty onto the single nearer lane of the receiving belt, mixing the contents of two lanes into one. This also halves the effective throughput of the receiving belt because two lanes are being forced into one.
If you are going to merge two belts, sideloading one belt onto the other is generally not advantageous because of the mixing problems described above. The recommended solution is to create a safe merge junction and a third belt: If both belts sideload onto the same tile from opposite sides, onto a belt unit that is perpendicular to both, then you get a safe merge junction, which is when the opposing belts load onto the opposing lanes and the contents of the two lanes do not mix.
Single-item versus multi-item belts
The simplest approach is one item type per belt. In this case you can ignore lanes and any inserter drawing from the belt is guaranteed to get the right item. The downside of this strategy is needing more belts overall and more space.
A more space-efficient approach is aiming for one item type per lane, which lets you fit two item types on the belt in total. This space-efficiency matters in crowded spaces, like when feeding assembling machines that require three or more types of ingredients. The one-type-per-lane arrangement requires you to be careful about where to sideload and where to have inserters deposit onto the belt. Nevertheless, the independent item streams work robustly.
Putting more than two item types on a belt can be pretty unreliable because it risks blocking the item flow. If inserters remove some item types but leave others, the unused items can accumulate and eventually fill up the lanes, blocking everything. Nevertheless, being extra meticulous about belt design is possible, such that you can reliably send an arbitrary number of different item types along the belt, creating what the community calls a sushi belt.
Transport line analyzer
The transport line analyzer is a Factorio Access tool for inspecting belt contents. Select a belt unit and press LEFT BRACKET to open it. The interface shows all items on the belt broken down by lane, as well as what is upstream and downstream from the selected unit. It also reads the ID assigned to the belt. Press TAB to switch between information tabs and use W A S D to navigate between lane views.
Building belts
Belts can be placed with precision when you use cursor mode but long segments require moving the character along with the cursor. A more practical option for building long belts is to use the Build Lock mode: Exit cursor mode, hold a stack of belts in hand, face the direction you want, and enable build lock with CTRL + B. When you walk in this mode, a belt is placed on every tile you step off. If you change direction while running, the belt in hand rotates to match, letting you build a belt that follows your footsteps, although this method sometimes misses corners.
Underground belts
Using automation science, you can unlock underground belts. Moving a section of a belt underground lets you make the belt avoid obstacles such as train tracks or other belts. Underground belt segments are always straight and they are built automatically when you place down the two belt chutes that define the start and end of the segment. While belts on the surface cannot cross over each other, underground belts can overlap without mixing.
A basic transport belt support underground segments that are at most 4 tiles long. Fast belts allow longer segments of 6 and express belts allow 8.
Beyond the basics
A single belt works as a great point-to-point transport solution. A group of belts that pour onto each other make a great item collection solution. Meanwhile, belts can also be used for distribution, sorting, load balancing, and other tasks, with the help of belt management machines called splitters.
Splitters and advanced belt topics are covered on the Transport Belt Systems page.
See also:
External links: