Two routes formerly diverged from the TVR's main line between Cardiff and Merthyr here – the Rhymney Railway's original main line northwards to Bargoed and Rhymney via Aber Junction (opened in 1858) and a much more recent spur to Nantgarw Colliery opened by British Railways in 1952 to permit the closure of most of the surviving Cardiff Railway route beyond Coryton. The Rhymney line, which diverged at Walnut Tree Junction just south of the station[2] was known locally as the Big Hill, due to its severe gradients (as steep as 1 in 48) for northbound trains. Increasing congestion on the 'main line' south of here led to the Rhymney company opening its own direct line via Caerphilly in 1871, but after the 1923 Grouping the Great Western Railway (and later BR) made extensive use of the line for its coal trains from the many collieries in the Rhymney Valley to the marshalling yards at Radyr. Both this line and the Nantgarw colliery spur are now closed and lifted - the last train down the Big Hill ran in June 1982,[3] whilst the latter branch was finally taken out of use in 1991 after the demise of the colliery and nearby coking works some five years earlier.
After the dismantling of the Viaduct, only one pier remains. This was used to display a goodwill message for Elizabeth II Silver and Golden Jubilee. These are still visible from the train approaching the station from the south.
The first City Line service of the day starts back from Taffs Well at 0653 to Coryton (with a 0704 departure from Radyr). There is no service in the opposite direction.
A reduced service operates in the evenings (3 trains per hour each way) and on Sundays.
