By 1 June 1854 the double line was extended from Pontypool Crane Street to Abersychan, but the rest of the line from Abersychan to Blaenavon remained single track.
The double line was extended from Pontypool Crane Street to Abersychan. This was by 1 June 1854. The rest of the line from Abersychan to Blaenavon remained single track.