The main-bus, explained without the cult: a Factorio starter layout

If you've watched any Factorio video you've heard 'main bus' said with the reverence of scripture. Strip away the cult and it's a simple idea: a handful of belts running in parallel down the middle of your base, carrying your core materials, with factories tapping off the sides. That's it. The reason everyone uses it is that it postpones the moment your base becomes unreadable spaghetti — and that moment is the real enemy.

What goes on the bus

Don't bus everything. Bus the things you use everywhere. For a starter base that's a short list:

• Iron plate, copper plate, steel — the metals everything needs.
• Green circuits (electronic circuits), because nearly every recipe wants them.
• Optionally: gears, plastic, and a lane of red/green science once you're producing it.
• Leave a gap, then a couple of lanes you reserve for 'later'. You will need them.

Four lanes of iron, four of copper, two of steel, four of green circuits is a perfectly sane starter. Space the lanes with a one-tile gap so you can route undergrounds cleanly. The single most common beginner mistake is packing the bus tight and then having no room to pull material across it.

Pulling off the bus without the mess

Here's the discipline that keeps it clean: every factory pulls material across the bus with underground belts, and every factory sits on one side, building outward away from the bus — never back into it. When you need a belt of iron at a machine, you run an underground under the lanes you don't need and surface where you do. Splitters with priority let you tap a lane without starving everything downstream.

The thing nobody tells beginners: the bus is a phase, not a forever. It gets you to blue science comfortably and falls apart somewhere around production science, when throughput demands more than belts can carry and you graduate to trains and modular 'city blocks'. That's fine. The bus did its job — it kept you sane long enough to learn the game.

A main bus isn't the optimal endgame. It's the training wheels that keep your first hundred hours legible.

So build one, don't over-think the lane count, leave room, and don't feel bad when you tear it down later. Tearing down your first bus to build something bigger is one of the better feelings the game has.