The South Wales Railway was incorporated in 1845 to build from the Great Western Railway at Gloucester through to Cardiff, Swansea, Carmarthen and Fishguard. The authorised capital was £2.8 million. Fishguard Bay was the destination as the strategic intention was to secure the Royal Mail contract for Dublin mails; the Great Western Railway had a close association with railway promoters on the Irish side, who would build a line from Wexford to Dublin. The South Wales Railway itself was an affiliate of the Great Western Railway, and was to be built on the broad gauge, and its engineer was Isambard Kingdom Brunel. The South Wales Railway Act also authorised a branch line from Whitland to Pembroke, taking a direct course and not running near Tenby.