Conveyor transport

Belts form directed chains of tiles; each tile holds a fixed number of item slots per lane and moves items forward at a tier-dependent speed. Items enter from inserters, machines, or side-loading and exit at the end, onto another belt, or into a machine. Splitters divide and merge flows, often with priority and filter settings; undergrounds and bridges cross other belts. Factorio holds 4 items per lane per tile and carries 15, 30, 45, or 60 items per second across both lanes for transport, fast, express, and turbo belts. Internally it groups adjacent belts into transport lines and stores the gaps between items, so a free-flowing line updates only its end gaps each tick. Satisfactory, Dyson Sphere Program, and Mindustry use similar belt tiers, and Shapez raises belt speed through upgrades. Inputs: items placed on belts. Outputs: items delivered at a throughput capped by the slowest segment.

Layout as the main puzzle. Players route belts around each other, balance lanes, and design compact buses, and they can see throughput problems as gaps or backed-up lines. A compressed belt feeding a full row of machines is a visible proof of a correct design.

• throughput per tier and number of lanes
• splitter, merger, and priority or filter options
• crossing options such as undergrounds, bridges, or vertical lifts
• item density and whether mixed items share a lane
• belt cost and unlock schedule

• Spaghetti layouts become unreadable and players stop understanding their own factory.
• Lane imbalance and side-loading rules are opaque without wikis.
• Belt counts at large scale cost simulation time; Factorio's transport-line rewrite was made to cut this cost.

• Main-bus and ratio-block conventions emerge from throughput caps, and players share them as blueprints.
• Belt saturation sets factory module sizes, so each tier upgrade reshapes layouts.
• Mixed-item belts create sushi designs and clogging failure modes.

• Could layout assistants that propose belt routing under player constraints keep the puzzle while removing tedium?
• What is the smallest set of belt primitives that still supports deep layout optimization?