Quakers' Yard in the Taff Valley was the location of an extremely busy railway junction from the middle of the 19th century until the period after World War II. It is so called as it was the site of a Quaker burial ground.

The Taff Vale Railway ran down the eastern bank of the Taff until it crossed it on an impressive viaduct designed by Brunel and built in 1840, with six broad arches. This viaduct still carries the railway between Cardiff and Merthyr and is the focus of this entry. The track of the Merthyr Tramroad also passed beneath it and is still visible from it. (see OTH entry Merthyr Tydfil)

Quakers' Yard was the point where the Taff Vale Extension (TVE) of the Newport, Abergavenny & Hereford Railway met the Taff Vale Railway. It also continued past the Taff Vale over a second viaduct and penetrated the hillside in the Cefn Glas tunnel to emerge in the Cynon Valley below Aberdare. It then continued all the way to Neath and Swansea. As an east west railway it had to cross the South Wales valleys over bridges and though tunnels. it is this viaduct which is featured in the illustrations here.

Subsequently the Rhymney Railway built a line from the TVE at Quaker's Yard up the west bank of the Taff to Merthyr, which entailed the building of a third viaduct, parallel to the second but curving away northward from it. this can also be seen in the illustrations.

Quaker's Yard had two stations, one on the TVE, 'Upper', and another on the Taff Vale, 'Lower'. This is the only station surviving as both the TVE and Rhymney lines have been closed and their viaducts demolished.