The Llanberis Lake Railway (Welsh: Rheilffordd Llyn Padarn) is a 1 ft 11+1⁄2 in (597 mm) narrow gauge heritage railway that runs for 2.5 miles (4 km) along the northern shore of Llyn Padarn in north Wales in the Snowdonia National Park.

[3] The quarry's workshops at Gilfach Ddu were purchased by the Gwynedd County Council with the intention of creating a Country Park.

These initial efforts at creating passenger stock proved unsatisfactory – they had a tendency to derail due to their very rigid construction.

The original terminus at Gilfach Ddu is now a through station serving both the National Slate Museum and the nearby Dolbadarn Castle.

On the return journey from Pen Llyn, passengers may alight at Cei Llydan station, where a picnic site is available with views of the Snowdonian mountains above Llanberis Pass.

[4] The railway uses three steam locomotives ("Elidir", "Dolbadarn" and "Thomas Bach") all of which ran on the internal 1 ft 10+3⁄4 in (578 mm) gauge lines of the Dinorwic Quarry.

When the Quarry closed down in 1969 the lakeside section of the trackbed was utilised for the current Llanberis Lake Railway, originally running from the National Slate Museum at Gilfach Ddu to Pen Llyn.