From Saturday 2 until Friday 8 July, the railway lines from Cardiff Central to Radyr (via Fairwater) and from Radyr to Pontypridd will close to trains.
Bus replacement services will be in operation and passengers should check for the latest information before they travel on the TfW website or mobile app.
The closure will allow TfW to carry out major transformational engineering work for the South Wales Metro.
This work includes the installation of foundations for overhead line equipment across Radyr and Cardiff lines, signalling installations and upgrades, level boarding and track work at Radyr and Treforest stations, vegetation clearance and preparation works at Danescourt, ground investigation surveys and general maintenance.
The South Wales Metro will significantly improve connectivity throughout South Wales and provide access to jobs, leisure and other opportunities for the people of Wales, through unifying rail, bus and active travel routes.
The project has been part-funded by the European Regional Development Fund through Welsh Government.
For more information visit https://tfw.wales/projects/metro/service-changes