 Throughout the first decades of the twentieth century, use of Llanelly Dock (now known as the Great Western Dock) declined; Swansea dock was nearer the centre of industry and was much enlarged and modernised over the years and Llanelly slowly became eclipsed.The Gwaun-cae-Gurwen improvements of 1907 had been followed up by obtaining powers on 18 August 1911 to build a through line from there to Felin Fran on the Swansea District Line, intended to further enhance the access to pits in the area.The line was partly constructed but never opened, due to World War I.