Factorio: The Beginner's Main Bus Design Explained
What a main bus is, why it's the most scalable starter base layout, and how to set one up from scratch.
What Is a Main Bus?
A Main Bus is a factory layout pattern where all key raw and intermediate materials travel down a central "highway" of belts, with production modules branching off to the sides. It's not the optimal endgame layout, but it's the most learnable, scalable, and repairable structure for beginners and intermediate players.
What Goes on the Bus
The standard main bus carries (from left to right, or in order of production):
- Iron Plates (4+ belts)
- Copper Plates (4+ belts)
- Steel Plates (2 belts)
- Green Circuits (4 belts)
- Red Circuits (2 belts — add later)
- Plastic (2 belts — once oil is running)
- Gears (1–2 belts)
The Golden Rule: Never Tap the Full Bus
When pulling from the bus, use a splitter to branch off a portion of a belt — never the whole belt. The belt keeps flowing for downstream users. Tapping the whole belt starves later production modules.
Leave Space Between Branches
Leave 4–6 tile gaps between each production branch. You will add inserters, power poles, and underground belts later. Cramped designs are painful to expand.
When to Switch to a New Layout
The Main Bus works until mid-game (launching the first rocket on easy mode). Beyond that, a "book" of blueprints or a smelting column setup scales better. Treat the main bus as a learning tool — the skills it builds (belt balancing, inserter ratios, module interaction) apply to every layout.