The Rook - vertical moves

The b-file is completely empty so the rook on b1 can travel the entire length of the board and occupy any square from b2 to b16.

The rook on d1 has its d-file blocked by a piece of its own colour. It can therefore occupy squares from d2 to d10.

The f-file is blocked by a piece of the opposite colour so the rook on f1 can occupy squares from f2 to f8 or capture the piece on f9.