1 had received a new boiler in 1913, which had seen little use, and in 1922 the railway began the process of creating one working locomotive from components of the three Hughes locos.

1 was rebuilt using parts from the other locomotives, but the resulting engine carried number 3, including its works plates.

[5] At the end of the 1920s negotiations began to sell the Corris Railway to the Great Western Railway and a report dated 12 October 1929 stated that locos 1 and 2 had been "marked off for some time as scrap";[7] they were handed over to a local scrap merchant and excluded from the assets taken on when the purchase was completed on 4 August 1930.

In the Great Western period the line was largely dependent on the slate output of Aberllefenni Quarry, which from 6 April 1935 was leased by the local member of parliament and owner of the Talyllyn Railway, Sir Henry Haydn Jones.

3 was still working when the Corris came under the control of British Railways following nationalisation in 1948, but operation under this organisation proved short-lived as the last train ran on 20 August that year.

[9] The Talyllyn Railway was built in 1865 and ran from Towyn (now spelt Tywyn) to the slate quarries of Bryn Eglwys, only a few miles from Corris.

[10] That same year, a group of enthusiasts, including the author Tom Rolt, started a society to operate the railway on a volunteer basis.

With the agreement of Haydn Jones' widow, control of the railway passed to the newly formed preservation society.

At the time, the crucial role that Haydn Jones had played in keeping the Corris running in the 1930s was not fully appreciated.

[14][15] Both railways were built to the unusual gauge of 2 ft 3 in (686 mm) which meant the Corris locomotives could run on the Talyllyn unchanged.

This problem was eventually cured by fitting wider wheel treads to Sir Haydn and by a Territorial Army members' exercise in 1953 that relaid the railway to its correct gauge.

Christopher Awdry wrote this into the 1985 book Great Little Engines, explaining that Sir Handel was visiting the line to help out.

An incident in which Sir Haydn ran into a tree branch and was given a bandage and eyepatch was turned into a story in the book, with almost no alteration from the real event.