Logic Masters Deutschland e.V.

My debut puzzle, enjoy.

Rules:

• Normal sudoku rules apply.
• Station cells: Mark some cells as station cells in the grid, one in every row, column and box. In addition, no two station cells may be in the same relative box position, and each station cell contains a unique digit. Rectangle cells are station cells.
• Train tracks: Draw a closed loop of orthogonally connected cells that does not touch itself, even diagonally. Circled cells and arrow bulbs are on the loop. Station cells cannot be on the loop. The digit 9 also cannot be on the loop.
• The loop must be orthogonally adjacent to each station cell exactly twice.
• Every pair of orthogonally adjacent cells that are both not on the loop must differ by at least 4.
• Arrows: Digits on an arrow sum to the connected circle.

Puzzle Link