North portal and wings of the Rock-fawr Bridge on Sir Robert Price's private tramway.

The North portal and wings of the Rock-fawr Bridge are part of Sir Robert Price's private tramway. The tramway bed is cut into the hillside, situated above the current A4063 road to Maesteg, with a leet running along the upper side of the formation. The bridge, which serves the driveway to Rock-fawr, features a semi-circular arch made of ashlar voussoirs in the retaining wall, although this arch is now blocked. It has a prominent keystone and a smaller arch for the leet on the right, which has been altered with brick, likely during the widening of the skew driveway that crosses over the angle on an iron plate. The bridge, or tunnel, is about 9 meters long and is partially blocked at its southern end.