Near Treforest, the Barry line and the former Llantrisant and Taff Vale Junction line ran close beside one another as they both diverged from the Taff Vale main line southwards. In 1930 a major redesign of the layout took place; the Barry route through Pontypridd to Trehafod was downgraded, and a new junction was created at Treforest, climbing to Tonteg where the Llantrisant and the Barry routes diverged. This was implemented on 10 July 1930, when the Barry passenger station at Pontypridd was closed.