Some of the many miles of tramroad on the hill known as Cribarth on the western side of the upper Swansea Valley are also deemed to form a part of the Brecon Forest Tramroad network, constructed as they were by Christie and his successors. These served numerous limestone quarries as well as sources of silica sand though it seems that the connection to extensive rottenstone workings to the north of Cribarth was not completed and did not come fully into operation.