Your belt spaghetti finally has a basement.

Beltlayer gives every surface its own underground floor where belts go to behave. Drop a connector, flip underground, and run your belts anywhere — around corners, under your factory, clear across the base — then pop them back up wherever you like. No length limits, no weaving through the mess, no "where do I even squeeze this one in." Just clean surface up top and a tidy world of belts humming away beneath it.

Why you'll want it

🧵 Untangle everything — send belts under the spaghetti instead of through it.

🌍 Reclaim your surface — move logistics downstairs and get your build space back.

➰ Route freely — corners, crossings, long hauls; the underground doesn't care.

🧱 Belts-only and rock-solid — focused on doing one thing flawlessly. (Out of the box, that's all it does — see the optional extras below if you want more.)

How it works

1. Connect — place a Beltlayer connector on the surface where a belt arrives.
2. Route — tap your editor-view key to drop underground, then lay belts, undergrounds, and splitters around anything.
3. Resurface — place another connector and your items ride right back up top.

The underground is a real surface you build on — what goes in one connector comes out the other. That's the whole trick.

What's in the box

• A belt connector for every belt tier you've researched — vanilla and modded.
• A dedicated underground editor for each surface, opened with a keybind.
• Belts, underground belts, and splitters down below — full routing freedom.
• Plays nice with blueprints, copy/paste, and the upgrade planner.
• Deconstruction is run by your surface construction bots (details in the FAQ).

⌨️ Bind your key: Settings → Controls → search "Beltlayer" → set Toggle editor view.

Optional extras (off by default)

Beltlayer ships belts-only for that clean, classic feel. Want the full toolkit? Flip any of these on in Settings → Mod settings → Startup and restart:

Underground circuit network — a circuit connector, underground power, and a logic kit (poles, combinators, lamps) so your red/green signals ride downstairs too.

Underground fluid network — a pipe connector so fluids travel underground through pipes, pumps, valves, and tanks.

Factorissimo 3 integration — every factory building gets its own underground, neatly confined to its footprint.

Terrain mirroring — undergrounds mirror the surface tiles directly above (water flattened to land, no cliffs or trees) instead of a plain floor.

Which version do I install?

Two builds live on this same page, and your game grabs the right one automatically:

• 🧪 Factorio 2.1 (experimental) → the latest build.
• ✅ Factorio 2.0 (stable) → a feature-identical legacy build, so existing saves keep right on running.

Same mod, same features — pick your Factorio and you're set. Nobody gets forced to upgrade.

💛 Recipes at a glance: belt connectors are cheap; the pipe connector costs 2× a pipe-to-ground, and the circuit connector 2× a medium electric pole.

FAQ

I marked something underground for deconstruction and nothing happened!
The underground has no bots of its own. Beltlayer hands the job to your surface network — it drops an invisible marker at the matching spot above ground, and your construction bots there do the work. Make sure a roboport covers that surface location and you're golden.

Will it wreck my existing save?
Nope. Install the build matching your Factorio version; 2.0 saves keep working on the 2.0 build, and updating won't disable features you've already switched on.

Can I run trains underground?
No — Beltlayer is belts-only by design. (An experimental subway system was tried and then retired to keep everything stable.)

The circuit / fluid / Factorissimo stuff is missing!
On purpose — those are off by default. Turn them on under Startup mod settings and restart.

Multiplayer?
Yep — each player gets their own underground editor view.

I toggled a feature off and my stuff vanished.
Startup settings rebuild prototypes, so turning a feature off removes its entities. Flip it back on if you change your mind.

Credits & license

Beltlayer is a continuation of Therax's original Beltlayer, with work by orillien and TeuLux. Released under LGPL v3, same spirit as the original. Massive thanks to Therax for the foundation this is built on.

Found a bug or have an idea? Swing by the discussion tab.