Tunnels
Train Tracks: Tunnels
Same row and column clues as classic Train Tracks — with a twist. Coloured tunnels join distant squares: enter one mouth and leave from its match. Boards stay solvable by logic alone.
See it in action
The extra rules
- Every usual Train Tracks rule still applies: one unbroken route, row and column totals, no branches or crossings.
- 5×5 and 7×7 boards have one tunnel pair; 9×9 boards have two. Each pair shares a colour.
- Entering a tunnel continues the route from the other tunnel of the same colour.
- Every tunnel square counts in its row and column total.
Sizes
Practice boards come in 5×5, 7×7 and 9×9, the same sizes as classic Train Tracks.
Why Tunnels
- It keeps the familiar clue-counting deductions while adding long-range connections to reason about.
- Matching colours make the pairs obvious, so you can focus on where the route must jump.
- When you finish, a train rides the path and slips under each collar into its chamber.
Who invented it
Train Tracks: Tunnels was invented by David Osahon in October 2026. Classic Train Tracks (also called Tracks or Rail Tracks) is a long-standing logic puzzle; this site’s Tunnels mode is Osahon’s addition.
Frequently asked questions
What is Train Tracks: Tunnels?
A variant of Train Tracks where coloured tunnel pairs let the route disappear at one mouth and continue at the other. All the usual row and column clues still apply.
Who invented the Tunnels variant?
David Osahon invented Train Tracks: Tunnels in October 2026.
Is it free?
Yes. Play in your browser with no sign-up.
Is it the same as classic Train Tracks?
The core rules are the same. Tunnels adds colour-matched portal pairs that join non-adjacent squares on the route.