A cable transportation system with at least one haul cable has a supporting structure (4) with a tubular portion (9) defining an axis of rotation (A); a pulley (5) extending about the axis of rotation (A); and a bearing assembly (14), which is connected to the pulley (5) and the tubular portion (9) to allow the pulley (5) to rotate about the axis of rotation (A) with respect to the supporting structure, and has a first and second bearing (17, 18) arranged concentrically and in series, so as to ensure rotation of the pulley (5) about the axis of rotation (A) and with respect to the supporting structure (4) by means of at least the first or second bearing (17, 18).