Nantlle Railway – Plas Dinas Map shows Plas Dinas tunnel on the left, Bronant to the right The most notable feature here is the tunnel under Plas Dinas driveway. Having passed under the WHR the route dives into a deep wooded cutting, the entrance to which is rather inconspicuous, only just visible on the right.of the picture. Ahead is Plas Dinas bridge. View looking back from within the cutting Ahead in the cutting lies the entrance to Plas Dinas tunnel which takes the line under the Plas Dinas driveway. Drystone walls line the sides of the cutting, and a stream flows at its foot The tunnel remains intact, although the original stone portal has collapsed at this end. The Royal Commission on Ancient and Historical Monuments in Wales records the tunnel as being 45.10 metres long, 2.45m wide and approximately 1.75m high, although silt from the stream has reduced the headroom over the years. It is brick lined and still in remarkably good condition In the distance beyond the tunnel the cutting curves round to the left towards the WHR again. The stone portal at the north end still stands and is in relatively good condition. When looking back towards Dinas, the north end of the cutting can just be seen on the left here behind the fence rails. The line passes under the WHR agsin here, well below the WHR track level. Plas Dinas bridge is visible in the distance.