The narrow gauge line was built from Dinas to Caernarfon in 1997, thus providing the extension to Caernarfon of the Welsh Highland Railway that was originally authorised by Act of Parliament, but never built. Between Caernarfon and Dinas, the new Welsh Highland line shares the old standard gauge trackbed with the 'Lôn Eifion' tourist cycle track. This section of line is operated by the Ffestiniog Railway under the provisions of The Caernarfon Railway Light Railway Order 1997 made 8 October 1997.