, where it diverges from the
Welsh Marches line Historically, the line was known as the
Central Wales line () and also included routes through
Gowerton, where the railway crossed the
West Wales lines and ran through
Dunvant and
Killay then down through the Clyne Valley to
Blackpill, and then along the sea wall to
Swansea Bay station, (near the former slip bridge) before finally reaching
Swansea Victoria railway station. This section, originally built by the
Llanelly Railway and Dock Company to compete with the
Great Western Railway and break the monopoly they held on Swansea Dock, closed in 1964.
Nationalisation of the railways had removed the need for competing routes, and the running down and closure of Swansea North Dock ended the need for freight services on this section. Trains now use the original LR main line to reach the
West Wales lines at
Llandeilo Junction and thence and (after a reversal) . North of , the route was opened in stages between 1861 and 1868 by a number of different companies (all backed by the
LNWR) – the
Knighton Railway, the
Central Wales Railway and
Central Wales Extension Railway. The 1963 Beeching Report proposed the entire Central Wales line be closed but this was refused by the MoT except for the Pontarddulais to Swansea Victoria section. As a rural branch line, it survived the
Beeching Axe since it carried freight traffic, serving the steelworks at
Bynea and industrial areas such as
Ammanford and
Pontarddulais, linking them with the docks at
Llanelli. It also passed through six
marginal constituencies. During engineering work, the line is still occasionally used as a diversionary freight route. The basic service over the line since the seventies has remained more or less constant, with four or five trains per day in each direction on weekdays and two or three on Sundays (although the latter ran in summer only until quite recently). The line is single track throughout (except for a few miles at the southern end shared with the
Swansea District line) and has been operated under a
light railway order since 1972. There are five
passing loops, at , , , and . Unless "Out of Course" working occurs the Llanwrtyd passing loop is used on two of the Monday – Saturday services and the Llandrindod passing loop is in use on the other two and also on the Sunday services. The signalling was modernised in 1986, when a system known as
No Signalman Token Remote working was introduced. This is overseen by the signaller at , with the token instruments at the aforementioned five passing loops being operated by the train crew (the surviving
signal boxes at each station having been closed as part of the modernisation scheme and the points converted to automatic operation by
British Rail). For more than two years only two of the loops (Llandrindod and Llanwrtyd) were operational as
Network Rail were unable to source spare parts for the points mechanisms used at all five: the design used is now obsolete. Parts had to be taken from the three decommissioned loops to keep the other two operational. In 2009 NR stated their intention to install new conventional electric point machines at all five loops and restore the three out-of-service ones to full working order (after being heavily criticised by the chairman of the South Wales branch of
Railfuture at the organisation's Annual General Meeting) but were unable to give a timescale for this to be carried out as design work on the new equipment was still ongoing. NR began the replacement works for the points after first installing the system on the line to Pembroke Dock, at the Tenby loop, on 7 December 2009 and then making minor alterations in Feb 2010. was the first on the line to be modernised, the rest followed. The £5 million project was completed in October 2010. In 2014 Network Rail added exit indicators at the trailing end of each loop to aid in the reversing of services: a decision taken so that all moves have an active indication of the status of the motor points. In 1987 tragedy struck the line near
Llandeilo when the
Glanrhyd Bridge collapsed following heavy flooding, and an early morning northbound train plunged into the swollen
River Towy, killing four people. For a while the future of the line was in doubt (the equally rural
Carmarthen-Aberystwyth line had been closed in 1965 following serious flood damage as the cost of repairs was deemed unacceptable) but political forces of all sides rallied to ensure the line's survival. ==Route==