Sir Haydn was built in 1878 by Hughes' Loco and Tramway Engine Works Ltd. He worked on the nearby Corris Railway until the closure of that line in 1948. In 1951, he was purchased by the Talyllyn Railway, along with the other surviving Corris locomotive, who became Edward Thomas, and was named after the line's late owner, Sir Henry Haydn Jones. The precarious state of the track meant he was seldomly used for the first few years, and firebox problems caused his withdrawal in 1957. He re-entered service in 1968.