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World 8 of 8

Unrailed 2: Back on Track: Underground Unit walkthrough

The secret puzzle biome: tunnels in, lasers, puzzle boxes on buttons, robots, and Dijkstra.

  • 3 parts · 13 steps
  • 1 boss

Steps from 8 text guides · checked Oct 19, 2026

0 of 3 done

What each player can do here

P1 · Gatherer
  • Gatherer: cuts wood and digs iron, carries it all to Storage (the Crafter draws from there on its own) and takes the bucket when the engine is getting dry.
P2 · Track layer
  • Track layer: lifts track off the Crafter and puts it down ahead of the train; between loads, opens the route and keeps an eye out for hazards.

If your skill levels differ: Blueprinted's two-player split gives one player gathering and water and the other track and hazards, and says both drop everything to lay track when the train is about to run out. The free Toy Engine restarts you at the last station after a crash, which suits learning a new biome.Our suggestionWhen skill levels differ: the steadier player takes track, since a missed rail ends the run. How to split the roles

Getting in and out

Part 1 of 3. Make it the last stop of a strong run.

  1. BothYou get in through a tunnel in a mountainside: at most one per level, rare on a first visit, and on every level once you are back in a biome for the second time.single source
  2. BothLeaving does not level up the engine, and this is the hardest biome, so save it for last.single source
  3. BothLeaving through the boss needs 5 Key extensions; beat it and the Secret Lab Facility Station sells only the Brakes extension and leads only to UnRailD HQ.
  4. BothWithout the keys, leave by a portal, found on every level after the first. It gives a single choice of biome and no cartridges or engine upgrade.single source
  5. BothWith Brakes on the engine, the train stops in front of UnRailD HQ at the end instead of crashing into it.single source

Lasers, puzzle boxes and robots

Part 2 of 3. Think before you clear.

  1. BothBlue lasers from turrets block all movement. A turret takes a few hits and falls to the axe or the pickaxe.
  2. GathererBeams are blocked by mountains, trees, rocks, the puzzle box and other turrets. A tree in a beam's way is protecting you, so leave it: clearing everything can trap you.single source
  3. Track layerThe station sits behind a shield; carry the puzzle box onto the one real red button to open it.
  4. BothIf you see two red buttons, one of them is the button robot B.U.T.T.O.N., given away by four black legs. Freed, it chases the nearest player and explodes a few seconds later, so clear the block at its corner first and strike it diagonally while it is still walled in.
  5. BothG.R.A.B.I.E. robots walk off with tools, even off the screen for good; dash into one to make it drop what it holds.

Boss: Dijkstra

Part 3 of 3. A puzzle under fire.

  1. BothStay near the train: it blocks the red laser. Never dash at a red laser.
  2. Track layerPhase one: carry the puzzle box onto red buttons to shut off the blue lasers, and check which button is really a B.U.T.T.O.N.
  3. Track layerPhase two: boxes on buttons also switch off the turning red turrets, or you can leave them on and dodge while laying track straight to the station.

Boss

DijkstraUnderground boss

  1. Both phases: Every resource sits in a heap along the bottom and a strip of water runs across the top; the boss moves along the top, shooting a red laser out of one eye and now and then a homing torpedo. Red lasers kill rather than block.
  2. Phase one: Blue lasers block the route until puzzle boxes sit on the red buttons.
  3. Phase two: Tools respawn near the train and turning red laser turrets line the middle of the route.single source
  • Hitting the red turrets with tools does not truly destroy them.
Sources (8)

Steps compiled from 8 text guides, checked Oct 19, 2026, and written in our own words. We did not play the game for this guide. A step marked “single source” rests on one guide so far.