According to The Island of Sodor: Its People, History and Railways, the people of the Arle Valley already had their own railway line which predated the Mid Sodor Railway by nearly two decades. The mine owners of Cas-ny-Hawin had consolidated together with people in the Arle Valley to build a small 2ft. 3in. gauge tramway to connect with the Port of Arlesburgh. At first the tramway was horse-worked, but they sought to follow the Skarloey Railway's lead of adopting steam traction to work their line, and by 1866, had an unspecified number of steam locomotives of their own, but were used for the mineral traffic only. Passengers were carried on the tramway, for free at their own risk, and charged only for the carriage of their hats, attire and other personal belongings.