 This line was that of the Carnarvonshire Railway (later LNWR and London, Midland and Scottish Railway), and joined with the Cambrian Coast Line at Afon Wen.Running alongside for part of the way is the trackbed of the old Nantlle Tramway, along which horse-drawn trams carried slates from the quarries in the Nantlle Valley to the port at Caernarfon from where they were exported.From Caernarfon to Llanwnda Station the Lôn Eifion runs alongside that of the Welsh Highland Railway.