The Padarn Railway was a narrow gauge railway line in Wales, built to the unusual gauge of 4 ft (1,219 mm). It was built to carry slate from the Dinorwic Quarry to Port Dinorwic. It opened in 1842, replacing the previous Dinorwic Railway. The Padarn Railway closed in 1961.
An unusual feature of the railway were the transporter waggons. These 4 ft (1,219 mm) gauge vehicles were flat wagons with two parallel 1 ft 10+3/4 in (578 mm) gauge tracks on them. Loaded slate wagons of 1 ft 10+3/4 in (578 mm) gauge - the gauge used on the extensive internal system at the quarry - were wheeled onto the transporter wagons and carried four at a time down to their destination at Port Dinorwic where they were unloaded via a 2 ft (610 mm) gauge incline which led to the quayside.
Since closure, part of its route has been reopened as the 1 ft 11+1/2 in (597 mm) gauge Llanberis Lake Railway.