The Ynysybwl branch line railway, formally known as the Clydach Valley Branch, was opened by the Taff Vale Railway company in 1885 to serve collieries that were expected to open in the Clydach Valley, Glamorganshire, South Wales. The branch line made a junction with the main line of the Taff Vale Railway at Stormstown, between Pontypridd and Abercynon (the station was then called Aberdare Junction). In fact the colliery development was limited, but the Lady Windsor Colliery became productive in 1886 and had a large output.
A passenger service to Ynysybwl was started in 1890, but it was not until the introduction of "motor cars", steam railmotor units that could stop at low-cost stopping places, and a diversion of the main line terminal to Pontypridd, that the passenger service was successful. The "Clydach Court Loop" was built to enable direct running to Pontypridd.
Nevertheless, the passenger income declined after 1918 and it was discontinued after 26 July 1952. Lady Windsor Colliery closed in 1988 resulting in the total closure of the branch line.
Taff Vale Railway main line
The Taff Vale Railway was authorised by Act of Parliament in 1836, with the principal objective of conveying the iron production of Merthyr and Dowlais to Cardiff for onward transport by ship; in addition there were connections to certain collieries, and the carriage of passengers was permitted. It was a standard gauge railway, engineered by Isambard Kingdom Brunel.
In fact the iron production at Merthyr was not as buoyant as was anticipated, but coal production expanded very considerably in the early days of the Taff Vale Railway company, and by the time the first main line opened to the public, on 9 October 1840, it was obvious that connecting to collieries off the original route was to be a priority.
New branches in to the Aberdare valley and the Rhondda were constructed, as well as numerous shorter connections to collieries close to those lines, and near the main line itself.
Authorisation
In the frenzied atmosphere of the Railway Mania, a huge number of railway schemes were put forward, many with little justification. The Taff Vale Railway presented a Parliamentary Bill in the 1846 session which included a proposed railway to a waterfall at Pistyll-goleu, near the present day Clydach reservoir, close to Llanwonno in the Clydach Valley. The gradients necessary to reach the chosen destination were difficult, and the technology of the day would have required operation partly by self-acting incline. The TVR already had one of these on its main line. The £59,204 estimated cost of the line and dubious benefits resulted in this scheme not progressing further.
By 1872 colliery growth in the Rhondda, not far away, was remarkably rapid, and it appeared likely that the Clydach Valley had potential too, and the decision was taken to build a branch line to handle the anticipated traffic. It was to run from near Llanwonno to a triangular junction with the TVR north of Pontypridd. In the 1873 session of Parliament this proposal, coupled with works on the existing Llancaiach line, was authorised by the Taff Vale Railway Act of 21 July 1873.
Construction delayed
The proposed branch was speculative, in the sense that large scale mineral output was not yet taking place at the mines to be served, and the TVR delayed construction of the line accordingly. In fact an extension of the time allowed had to be sought in 1877 and it was October 1880 before a contract was let, to J E Billups. Nevertheless, mining activity in the area was limited, with only the Mynachdy and Black Grove collieries providing business at this stage.
The line probably opened in 1885.
Collieries
Towards the end of 1884 a company called Davies, Scott and Company was formed to undertake more ambitious mining work. A pit, to be named the Lady Windsor Colliery, was to be sunk, and this was done in 1885, with commercial output starting at the end of 1886. The pit proved successful and its production was on a large scale: it employed 891 men in 1890. A general goods depot was opened at Ynysybwl by July 1886. The considerable increase in mineral traffic overwhelmed the capacity of the branch facilities, and at the same time a request for a passenger service was submitted.
The branch was extremely steeply graded as its extremity was approached, reaching 1 in 30, and for many years trains were propelled beyond Mynachdy for safety reasons.