The City Line is a commuterrailway line in Cardiff that runs from Coryton to Radyr via Cardiff Central. Regular passenger services on this route started in 1987. Passenger trains run from Monday to Saturday. The line is also used as a diversionary route for trains to Merthyr, Aberdare and Treherbet when the line between Cardiff Queen Street and Radyr is closed for engineering work. Past services on the line saw shuttle services over the line to Pontypridd and beyond with one stop at Ninian Park.
The line is currently operated by Arriva Trains Wales (ATW) as part of the former Valley Lines network. ATW replaced the previous franchise Wales & Borders Trains in December 2003. Some freight services also use the line.<br clear=all>