Railpair Navigator

In this city's subway network, you play as a route planner. Each number on the board represents a pair of stations with the same name, and your task is to connect them using subway lines of different colors. Lines can only extend horizontally or vertically, and cannot intersect, overlap, or pass through other stations. Crucially, every city block must be passed through exactly once by a particular line—the entire map must be completely covered by your tracks for the network to be considered complete. The game includes multiple difficulty levels, daily challenges, achievements, and a statistics system.