How to play Train Tracks: Tunnels

If you already know classic Train Tracks, you only need the tunnel rules. If you are new, start with the classic rules, then add tunnels.

Classic rules (unchanged)

Lay one unbroken track from the entrance tab to the exit tab. Numbers beside each row and column say how many squares hold track. The path never branches or crosses itself. Read the full classic rules if you need them. Classic how to play.

Tunnel rules

1. 1Find the matching mouths

   Tunnels come in colour pairs — purple with purple, amber with amber. 5×5 and 7×7 have one pair; only 9×9 has two.

2. 2Treat a pair as one connection

   When the route enters one mouth, it continues from the other mouth of the same colour. Mentally join those two squares on the path.

3. 3Count every tunnel square

   Each tunnel cell still counts toward its row and column total, just like ordinary track.

4. 4Finish with a complete route

   The finished board is still one continuous journey from entrance to exit, including the jumps through matching tunnels.

Solving tips

• Mark forced tunnel links early

  If a tunnel square must hold track because of its clue, its colour twin is also on the route.

• Watch the approach cells

  Only one neighbouring square can feed each mouth. Crossing out the wrong approaches often unlocks the rest of the board.

• Use classic deductions first

  Zeros, full lines and dead ends still do most of the work. Add tunnel jumps once the local clues are tight.