Complex sentence: 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.
Split into simpler sentences: By 1 June 1854 the double line was extended from Pontypool Crane Street to Abersychan. The rest of the line from Abersychan to Blaenavon remained single track.