The Ffestiniog Railway (Welsh: Rheilffordd Ffestiniog) is a narrow gauge heritage railway, located in Gwynedd, Wales. It is a major tourist attraction located mainly within the Snowdonia National Park.
The railway is roughly 131⁄2 miles (21.7 km) long and runs from the harbour at Porthmadog to the slate mining town of Blaenau Ffestiniog, travelling through forested and mountainous scenery. The line is single track throughout with four intermediate passing places. The track gauge is 1 ft 11 1⁄2 in (597 mm) allowing trains to interwork through to the Welsh Highland Railway of 1922 (operated by the Ffestiniog). The first mile of the line out of Porthmadog runs atop an embankment locally called “the Cob”, which is the dyke of the Traeth Mawr “polder”.