How to solve Train Tracks puzzles, one clue at a time

A Train Tracks puzzle asks you to work out where the track belongs. You have a grid, a set of clues and a route to discover.

At first, several squares may look possible. The enjoyable part is finding a clue that makes one decision certain, then seeing what that decision tells you next.

Let's start with a small route puzzle. Loop puzzles have a different finishing goal, so we'll leave those for another day.

What the numbers tell you

The clues beside the rows and columns tell you how many squares in each contain track. A clue counts occupied squares, not the number of lines you draw inside them.

Your route connects the marked start and finish. Track joins through the sides of squares, using straight sections and bends. It cannot branch, cross itself or leave disconnected pieces behind.

Always check the printed instructions for a puzzle's particular conventions, including how its endpoints are shown.

Start with the clearest counts

Look for a row or column that is already full, or one where every square must contain track.

If a four-square row has a clue of four, all four squares contain track. That doesn't necessarily mean the route runs straight across them. The count tells you which squares are occupied; the connections still need to be worked out.

If a row needs only one occupied square and its marked starting square already supplies that one, the other squares in the row must stay empty.

Marking an empty square can be just as useful as drawing track. It removes a possibility and may force the route in another direction.

Try the little example

Our teaching grid is four squares wide and four squares high. The row clues, from top to bottom, are 1, 3, 4 and 3. The column clues, from left to right, are 4, 3, 2 and 2.

The start is in the top-left square. The finish is in the bottom-right square.

A grid four squares wide and four squares high. Row clues from top to bottom: 1, 3, 4, 3. Column clues from left to right: 4, 3, 2, 2. The start, A, is the top-left square and the finish, B, is the bottom-right square.

The top row needs only one track square, so its starting square fills that row's count. Mark the other three squares empty. The first column needs four track squares, so every square in that column is occupied. The third row also needs four, so every square in that row is occupied.

The same grid after the first deductions. The other three squares of the top row are marked empty. Every square in the first column and every square in the third row is marked as holding track.

Notice how much you can establish before drawing the whole route. Now work out how those occupied squares can join while respecting the remaining counts and avoiding a branch or a crossing.

Open the solution when you're ready, and trace it from start to finish. Check each row and column as you go.

Show the solution

The route runs down the first column from A to the bottom row, one square right, up the second column to the second row, one square right, down to the third row, one square right, and down to B in the bottom-right square.

Common places to get stuck

Connecting occupied squares too soon. Two squares can both contain track without the track joining directly between them. Keep the route's actual connections in mind.

Forgetting a completed count. When a row has all its required track squares, mark the remaining squares empty. Otherwise it's easy to accidentally use one later.

Creating a separate little route. The finished route needs to connect the start and finish as one path. A section that can never join the rest is a sign to look again.

Guessing before checking the other direction. If a row isn't helping, look at its columns. A new empty square or occupied square can change what is possible there.

Ready for more tracks?

My Train Tracks book includes 300 puzzles: 150 routes and 150 loops, with easy, medium and hard challenges and full solutions.

Start with the route instructions and an easier puzzle, then explore the loop section when you'd like a different goal. You don't need to race. The satisfying moment is when the clues leave just the right place for the next piece of track.

Print a free Train Tracks puzzle