Colbren Junction station, which opened in 1873 at the same time as the new route, was situated at the point where the original Neath and Brecon line met the new branch to Ynys-y-Geinon.
The station consisted of three separate side platforms.
As the Neath line was on a falling gradient, while the branch rose before commencing the descent to the Tawe valley, the branch's two platforms were built at a higher level to the single Neath side platform.
Access between the upper and lower central platforms was by a short flight of steps.

Although the Midland Railway had constructed a line into South Wales, it still needed to negotiate operating powers with several rival companies to make the route viable.
These included the London and North Western Railway which reached Swansea via its Central Wales route in 1868.
The Midland first leased, in 1874, and then acquired the Swansea Vale Railway in 1876; while exchanging running powers with the Neath and Brecon.
A similar procedure was then employed with the Hereford, Hay and Brecon Railway; its running powers were passed to the Great Western.
In doing so, the Midland was able to link with its main national network at Worcester.

The outcome of these complex arrangements allowed the Midland to become the sole operator of the Brecon-Colbren-Ynys-y-Geinon-Swansea route, thus reducing the original main line between Colbren and Neath to the status of a branch.
Until 1916 the Midland ran its trains beyond Brecon to Hereford, with parts of trains running directly to and from Worcester and Birmingham.
Eventually these services were cut back to Brecon.
Colbren Junction station, which opened in 1873 at the same time as the new route, was situated at the point where the original Neath and Brecon line met the new branch to Ynys-y-Geinon. The station consisted of three separate side platforms. As the Neath line was on a falling gradient, while the branch rose before commencing the descent to the Tawe valley, the branch's two platforms were built at a higher level to the single Neath side platform. Access between the upper and lower central platforms was by a short flight of steps.
Although the Midland Railway had constructed a line into South Wales, it still needed to negotiate operating powers with several rival companies to make the route viable. These included the London and North Western Railway which reached Swansea via its Central Wales route in 1868. The Midland first leased, in 1874, and then acquired the Swansea Vale Railway in 1876; while exchanging running powers with the Neath and Brecon. A similar procedure was then employed with the Hereford, Hay and Brecon Railway; its running powers were passed to the Great Western. In doing so, the Midland was able to link with its main national network at Worcester.
The outcome of these complex arrangements allowed the Midland to become the sole operator of the Brecon-Colbren-Ynys-y-Geinon-Swansea route, thus reducing the original main line between Colbren and Neath to the status of a branch. Until 1916 the Midland ran its trains beyond Brecon to Hereford, with parts of trains running directly to and from Worcester and Birmingham. Eventually these services were cut back to Brecon.
Colbren Junction railway station