* Annual estimated passenger usage based on sales of tickets in stated financial year(s) which end or originate at Ystrad Mynach from Office of Rail Regulation statistics. Methodology may vary year on year.
Ystrad Mynach railway station was on the Rhymney Railway, enacted in 1855 and opened in 1858. It consisted of staggered platforms on the main line, as well as a separate platform on the Dowlais line. Nearby Penallta Junction gave access to the Great Western Railway and the Aberdare Valley, opened 1 April 1871 and the Cylla branch opened on 1 August 1906 to access the new Powell Duffryn owned Penallta Colliery. The latter line closed in 1991 and has since been lifted, but the former is still in use (for freight only) as far as Cwmbargoed to serve the coal washery and associated opencast mine at Ffos-Y-Fran. Coal from there is sent to Aberthaw Power Station in bulk trainloads.
The northbound platform is signalled for use in both directions, to permit trains from Cardiff to terminate & start back from there.
The station has a frequent weekday service in both directions - northbound there are four trains each hour to Bargoed (one service terminates here during the autumn leaf fall period), with hourly extensions to Rhymney (extras at peak times) on Mondays to Saturday daytimes, whilst southbound there are four trains per hour to Cardiff Central and Penarth. Connections for Barry Island and Bridgend via the Vale of Glamorgan Line (as well as main line destiantions further afield) are available at Cardiff Central.
In the evening, there is an hourly service to Rhymney & Cardiff/Penarth and on Sundays there is a two-hourly service each way, with southbound trains running to Barry Island.