On 1 January 1948, the line was nationalised along with its parent company, becoming part of British Railways (BR). While the GWR had tolerated the Corris, BR was looking for an excuse to close the loss making railway. In August 1948, that excuse came when the River Dyfi flooded. The waters began to undermine the Corris Railway embankment on the south side of the Dovey Bridge, and although the track was never breached, it was the excuse that BR needed to close the line. The last train ran on 20 August 1948 and the following day the railway was closed, without notice. The Aberllefenni to Corris section was lifted in November 1948, and 10 tons of the rail was purchased by Henry Haydn Jones for use on his Talyllyn Railway. By the end of 1950, track lifting had reached Machynlleth station.
On 1 January 1948, the line was nationalised along with its parent company, becoming part of British Railways (BR). While the GWR had tolerated the Corris BR was looking for an excuse to close the loss making railway. In August 1948, that excuse came when the River Dyfi flooded. The waters began to undermine the Corris Railway embankment on the south side of the Dovey Bridge, and although the track was never breached, it was the excuse that BR needed to close the line. The last train ran on 20 August 1948 and the following day the railway was closed, without notice. The Aberllefenni to Corris section was lifted in November 1948, and 10 tons of the rail was purchased by Henry Haydn Jones for use on his Talyllyn Railway. By the end of 1950, track lifting had reached Machynlleth station.