Construction started on 2 September 1800, relaying and extending the Llandegai Tramway, with the first slate train traveling on 25 June 1801. The new railway was also gauge. The connection to the Llandegai flint mill continued to be used until 1831. The railroad was operated by horse power along with gravity and three balanced inclines – "Port" (sometimes called "Marchogion") near Llandegai, which was inherited from the Llandegai Tramway, "Dinas" north east of Tregarth and "Cilgeraint" a short distance north of Coed-y-Parc workshops in Bethesda. The longest extended for 220 yards. With hindsight this seems hard work, but the overall gain was remarkable, shown not least by the cost of transport falling from 4 shillings per ton to 1 shilling