The FR continued to operate its slate traffic, a workmen's train on weekdays throughout the year and a summer tourist passenger service. Ordinary passenger services ceased on the FR on 15 September 1939, shortly after the outbreak of World War II. The workmen's passenger service ran for the last time on Saturday, 16 September 1939. Slate trains were from then onwards operated three days each week but gravity operation was discontinued. Slate traffic ceased on 1 August 1946, apart from the section from Duffws to the North Western yard through Blaenau Ffestiniog town centre, which was leased on 7 October 1946 to the quarry owners. This provided the railway company, which retained the services of a resident manager at Porthmadog, with a small income throughout the moribund years.
