The Great Western Railway opened its line between London and Bristol in 1841. A branch to Gloucester and Cheltenham was built by the Cheltenham and Great Western Union Railway. The GWR encouraged the formation of what was to become the South Wales Railway to build a line from near Gloucester through Cardiff and Swansea to Fishguard. The South Wales Railway obtained the Royal Assent on 4 August 1845. The line opened progressively: from Swansea (Landore) to Carmarthen on 11 October 1852 and to Haverfordwest and Neyland on 2 January 1854. Radically changed economic conditions put reaching Fishguard in abeyance.