Plas y Dduallt, literally the "house on the black hillside", is steeped in history and folklore. Set high up in Snowdonia National Park, this Grade II listed building borders the Ffestiniog Mountain Railway and the Maentwrog Nature Reserve. It is one of the oldest inhabited houses in Wales, dating back to the 15th century, and access until the 1960s was either on foot or by train. Now, guests can use a steep tarmac drive that winds its way for half a mile, climbing 500 ft through ancient woodlands, although old habits die slowly and train access is preferred.

Colonel Campbell restored and renovated the property in the 1960s. The colonel was quite a character and a great friend of the railway. He used his explosives expertise to help blast the new route for the Ffestiniog Mountain Railway, which runs above the house, about a minute's walk from the front door. From March until October there are quite a few trains each day. On a busy day in August there are eight trains up the line and eight trains down. Guests stick out their hand from Campbell’s platform, their own private halt, and a steam train will grind to a halt.

The platform provides a great vantage point from which to appreciate trains coming up the line. You can hear the distant whistle as they pull away from Tan y Bwlch station and, as they approach, the plumes of steam puff out above the trees. Finally the train emerges round a bend, a panorama of a dozen carriages chugging their way up the hillside.