Burry Port and Gwendraeth Valley Railway
The Burry Port and Gwendraeth Valley Railway (or Burry Port and Gwendreath Railway, owing to a spelling mistake in the Act of Parliament creating the railway) was a 21-mile long railway progressively opened between 1859 and 1891 as a coal carrier.
1866 The company dates from 1866. The line is 21 miles in length. 
The railway ran largely on the route of an earlier canal built by Thomas Kymer to bring coal down the valley. It also operated dock facilities at Burry Port. The railway was poorly managed in the nineteenth century and often bankrupt. Increasing traffic at the turn of the century and intelligent management transformed it as a business and Holman Fred Stephens was employed as a consultant in 1908 to reconstruct it to legalise its unofficial carrying of passengers. The necessary legislation was obtained in two Light Railway Orders in 1909 and 1911. Stephens supervised re-construction and re-equipment over the years up to 1913 after which he had no further connection.
The railway itself split from the South Wales main line near Llanelli, actually joining via the Llanelly and Mynydd Mawr Railway and then followed the same general path as the main line with stations at Burry Port, Pembrey (both separate to the mainline stations), before turning up the valley and calling at Craiglon Halt, Pinged, Trimsaran Road, Pont Newydd, Ponthenry, Pontyates and Pontyberem as well as the mine at Cwm Mawr. A separate branch ran from Kidwelly where the Gwendraeth Valley railway met the South Wales main line through Ty Coch, where it became the Burry Port and Gwendraeth Railway. There were plans originally to extend the railway up through the valley beyond Cwm Mawr to join the now defunct link between Carmarthen and Llandeilo at Llanarthney.
Various small branches from the Burry Port and Gwendraeth Valley Railway fed out to the collieries and also small villages like Rhiwlas and Llandyry.
1923 The railway was absorbed by the Great Western Railway and in turn by British Railways in 1948. Throughout its life time the railway kept an unusual style. The fact it was built down the old canal route meant that the line was not only prone to flooding but had low bridges and sharp curves. This always posed a problem to the railway operators as very little rolling stock could traverse the line safely. Despite the problems passenger traffic lasted until 1953. The freight service continued far longer and coal traffic continued until 1996 when the local mines closed down. In later years the restrictions on the line meant that British Rail maintained several specially height reduced shunters to pull the coal trains down the line. For a long time two or even three class 03 shunting locomotives would make the slow trek down the valley with thirty coal wagons in tow, often down a line that was several inches under water. In the later years British Rail cut down the cabs and tops of several class 08 locomotives to fulfill the same role, the line being incapable of supporting normal freight locomotives or even unmodified shunters.
Most of the track was lifted by 2005 with the track between Burry Port and Trimsaran Road lifted much earlier (as the freight trains used the Kidwelly route). There has been some discussion of preserving the railway however the tight clearances and light construction of the line would be a problem. Parts of the route can be walked as part of the Pontiets (formerly Pont Yates) mining heritage trail. 
Sources of Information
- The Stock Exchange Year Book 1908
-  Wikipedia
- Encyclopedia of British Railway Companies by Christopher Awdry. Published 1990
-  Wikipedia