The Doppit Almanac · No. 22

Trackit, a daily Train Tracks puzzle

Lay a single track to match the counts

What it is

Trackit is Doppit's daily Train Tracks puzzle, No. 22 in the almanac. The rails enter the board through one wall and leave through another, and your commission is the line between: one unbroken run of track, and the counts along the edges say exactly how many track cells each row and column carries.

The line never branches and never loops. It simply goes, and the counts leave it precisely one way of going. Zero is the kindest clue in the game: a row marked 0 never carries track, and you may rule out the whole of it at once.

How it plays

The working timetable is short.

• Lay one continuous line of track from where the rails enter to where they leave.
• A single line: no branches, no loops.
• Every row and column count must land exactly, neither over nor under.
• Dots mark cells you have ruled out. They are notes, not track.
• Lay the cells and the rails bend themselves to follow your line; the ironwork sorts out its own curves.

The difficulties

Three services run daily. Easy pulls in at thirty seconds to a minute. Medium keeps you on the platform for one to three. Hard is a three-to-six-minute negotiation with the branch lines, and counting settles every cell of it. Expert is a fourth service, kept for practice and never dealt as the daily. It runs on hard's own eighteen by eighteen with a shorter line and fewer cells printed, and counting will not finish it. You suppose the line runs through a cell, follow the forced moves, and wait for a rule to break. Several times a board that is not enough on its own, and you have to suppose a second cell inside the first. A new route is drawn every day, and no fare is collected at either gate.

Nearby in the almanac: Pipeit, Nonit and Yinit