The first section of the South Wales Railway, that between and, opened on 18 June 1850. The original stations on that line included one named Llantrissant for Cowbridge. The station became a junction with the opening of the first section of the Ely Valley Railway to on 2 August 1860, although passenger services along that line did not begin until 1 August 1865. The EVR opened a branch to Brofiskin Colliery in 1862, and another railway, the Llantrisant and Taff Vale Junction Railway, which opened in December 1863, intended to use part of that branch to gain access to Llantrisant via a connection at Maesaraul Junction, but in order to do this, the Brofiskin branch had to be altered to mixed gauge - this occurred in December 1864. The station name was simplified to Llantrissant, by which time the SWR had amalgamated with the Great Western Railway in 1863. Adjacent to this station was the terminus of the Cowbridge Railway, which opened on 18 September 1865, originally being named Llantrissant. The Cowbridge Railway was leased by the Taff Vale Railway in 1876, and absorbed by that concern in 1889. Both the GWR and TVR stations had their names amended to Llantrisant by 1902. The TVR in its turn amalgamated with the GWR on 1 January 1922, and on 21 September 1925 their respective stations were merged as a single station. Llantrisant was a major intermediate station on the South Wales Main Line. It consisted of two central through platforms and bays for the Ely Valley line, the Llantrisant & Taff Vale Junction line and the branch to Cowbridge and Aberthaw. The station was closed on 2 November 1964. Under the auspices of Regional Railways sector of British Rail and Mid Glamorganthe station was reopened. The station was rebuilt and reopened as Pontyclun on 28 September 1992. Extensive sidings existed around the station for the coal and mineral traffic generated by the mines in the area. At least the line to Cwm Colliery was in regular use until 1984.
A single track railway runs north from Pontyclun station - the remnants of the Llantrisant and Taff Vale Junction Railway. The track turns east at Talbot Green to run roughly parallel to the Afon Clun, alongside the north of the A473, which runs between Pontypridd and Bridgend. At Cross Inn the track turns north east, running south of Llantrisant and north of Caerau Hillfort, an Iron Age enclosure. Originally, it ran to the Cwm Coking Works at Tynant, Beddau, just past the former station Llantwit Fardre, although the track has been totally dismantled and the trackbed is now a cycle path that currently terminates at Westfield Crescent, Cross Inn. None of the original railway paraphernalia remains intact between Talbot Green and Pontyclun, apart from a footbridge with cages above the former track that crosses the A473 where it meets the A4222 near Leekes. The track remains embedded in the road where it crosses the A473, and warning lights were at the roadside and road signs warned drivers to stop if they saw warning lights flash at the level crossing but these were removed during construction of the cycle path. A consultative study in 2006 considered the possibility of reopening the Pontyclun to Beddau branch line, as a passenger line rather than just for freight. This would require new stations at Talbot Green, Llantrisant, Gwaun Meisgyn and Beddau.
Services
Mondays to Saturdays there is an hourly service eastbound to, with most continuing to,,, and Cheltenham Spa, as well as an early-morning service to Manchester via Cardiff, Newport and the Welsh Marches Line via, and. The station has an hourly service westbound to and and eastbound towards, with some services continuing on towards,, and. These services are operated mainly by Class 170Turbostar units. On Sundays the service decreases slightly. There is roughly a 2-hourly service to however there are also four services a day to via and, the latter of which is usually operated by either Class 158Express Sprinter or Class 175Coradia units. A few early morning and late evening services take the spur to to continue onto alongside Canton sidings, to retain route knowledge.
Pontyclun station is unstaffed. It has neither ticket gates nor barriers. The station has no ticket office. passengers can purchase tickets from the station platform self-service ticket machine, on board trains or at their destination. Both platforms have shelters. The station car park is free-of-charge to rail users. A locomotive depot, known as Llantrisant, was situated between the station and Mwyndy Junction, on the eastern side of the curve. It housed around 20 locomotives, and closed in October 1964.
