Sandustry Conveyor Portal Guide: Cross Lines Without Mixing

Understand the machine's job before placing it

Conveyor Portals solve a geometry problem: two material routes need to cross, but a normal junction would mix them. Treat the portal as a transport boundary with a defined entrance and exit. The crossed route remains physically separate only when both portal directions and nearby cells are built correctly.

The official Research page currently lists Conveyor Portal at 750 Gold. That page is still being developed, so confirm the cost and prerequisite in the live technology tree before committing a long unlock route. The function of crossing lines without mixing is the durable planning reason to reserve space.

Follow the documented input and output rules

A portal moves a conveyor stream across another line while preserving separation. It does not sort an already mixed input. Feed one identified material into the entrance during commissioning and collect it in an empty pocket at the exit. Test the crossed line independently before running both together.

Direction and clearance matter at both endpoints. If the destination is full, the entrance can appear broken even when the portal link is valid. Trace material from the source to the entrance, through the pair, and from the exit to storage as three separate boundaries.

Build a serviceable layout

Reserve a rectangular service zone around both ends and keep the crossed route visible. Add a shutoff before each line so one can be tested while the other remains empty. Avoid placing a second portal pair so close that entrances or exits become visually ambiguous.

Use portals where they remove a real crossing constraint, not as default transport for every short gap. Conventional conveyors are easier to observe and repair. A portal earns its space when it preserves two readable modules and prevents a mixed junction that would otherwise require complex filtering.

Measure sustainable throughput

Treat Conveyor Portal pair as one boundary in a longer chain. Start with empty or recorded buffers, count how much a controlled conveyor material stream reaches the input during a fixed interval, and compare that with the same stream beyond a non-mixing crossing leaving the output. Record material still inside the chamber. A growing reserve before the machine identifies an intake or processing limit; a growing reserve after it identifies a collection or destination limit.

Do not infer an exact rate from a short animation. Let startup material clear, repeat the interval, and test again after saving and loading. If supply arrives in bursts, record both average flow and the largest burst. Add parallel capacity only after the same boundary limits two clean observations. Otherwise extra machines can hide a routing fault while consuming space, power, heat, cold, or scarce construction resources.

Diagnose the first failed boundary

If material reaches the entrance and stops, inspect pairing, direction, and output capacity. Empty the destination and try a single sample. If material exits but joins the crossed line, inspect the cells immediately after the portal; the portal may have worked while the ordinary output geometry recombined the streams.

If an older world contains a portal that remains stuck, confirm v0.5.6 and test after a save and reload. Update #3 includes a stuck-portal fix. Preserve the original world before removing the pair, and rebuild only after the current-version test shows the problem persists.

Apply the v0.5.6 version notes

Version 0.5.6 fixes Conveyor Portals becoming stuck. Remove workaround bypasses one at a time and observe the route through a restart. A repaired transport path may expose a downstream buffer that had filled while the portal was inactive.

Research data can change during Early Access, and the official Research page is marked as work in progress. Treat 750 Gold as the checked current table value, show the date with this article, and verify the in-game tree after any progression update.

Validate the design in a small test cell

Build one isolated Conveyor Portal pair with a limited input sample, visible output pocket, and a way to stop supply. Label the game version and active mods. Observe the expected transformation, any byproduct, where each pixel settles, and what happens when the destination fills. Then clear the cell and reverse the loading order if two materials share space. A repeatable small test gives a stronger design basis than a screenshot of a large factory.

After the test passes, copy the geometry into production while keeping access to the input, output, and removal controls. Leave enough room to inspect or drain the machine without opening a neighboring line. Recheck the route after patches that mention the machine, its materials, density, heat, fluids, energy, or building events. Keep the prior measurement with its version so a future change is visible instead of becoming an unexplained slowdown.

Use the pre-launch checklist

Before opening full supply, confirm that the input really is a controlled conveyor material stream, the planned result is the same stream beyond a non-mixing crossing, every required power or temperature connection is active, and no incompatible material can enter. Verify output clearance, overflow capacity, a shutoff point, and a safe path for the player. Take one recovery save before connecting a rare or destructive input.

During the first long run, compare starting and ending inventory at every boundary. Watch for material trapped inside building cells, a mixed network, a full destination, and a reserve that only delays failure. If the line remains balanced through its normal burst and restart conditions, record the observed rate and promote the module as the factory's current versioned standard.

Field facts

Troubleshooting

• Material stops at a portal entrance.

  Clear the exit and destination, confirm direction and pairing, then retry one sample on v0.5.6.

• The two lines mix after the crossing.

  Inspect ordinary conveyor cells immediately after the portal; keep each exit on a separate route.

• An old portal remains stuck after updating.

  Preserve the save, reload on v0.5.6, test an empty destination, and rebuild the pair only if the fault remains.