In later years the line saw a variety of GWR locomotives operating from pit to port; however, the railway retained its LNWR infrastructure up until the last days before its closure.
The line was closed to passengers, not during the Beeching Cuts which befell the GWR route to Blaenavon Low Level, but in 1941 due to the exigencies of the Second World War.
The declining situation continued through the 1950s, then Varteg Hill subsequently closed in 1964 leaving Big Pit as the primary exporter of coal left.
Although passenger and goods traffic had long ceased to Brynmawr the track was re-laid by the NCB to just south of Waunavon station again during the 1970s for the Black Lion Disposal Point washery.
The 13-mile long section from Llantarnam Junction on the Newport-Hereford line to Furnace Sidings remained in use for coal trains from other local mines until 3 May 1980 following the closure of Big Pit.
The Pontypool Blaenavon Railway Company was then granted an Order under the Transport and Works Act to extend and operate the line.
Eventually, restoring and reopening the entire existing route from Brynmawr station to Pontypool Wainfelin marks the long-term goal and aspirations of the society.