Railway services between mid and south Wales could be cancelled for up to eight weeks.
The Heart of Wales line between Llandrindod Wells and Llanelli is closed due to a damaged bridge near Pontarddulais.
Replacement bus services between the two towns will run in both directions until further notice. Train services will run between Shrewsbury and Llandrindod Wells, and Swansea and Llanelli.
Transport for Wales said: "Due to structural damage to the bridge between Pontarddulais and Hendy Junction, it is unsafe for trains to pass over the bridge".
"Services will start and terminate at Llandrindod Wells until repairs are complete. This may take up to eight weeks.
"Road transport will be provided between Llanelli and Llandrindod in both directions until further notice".
On Monday morning, Network Rail tweeted to say that it was "working hard" to repair the bridge and make it available to run a normal service from Monday, August 3.
For the latest railway line updates, go to www.journeycheck.com/tfwrail/.
❗️❗️❗️ UPDATE ❗️❗️❗️
— Wales & Borders #BeSafeBePatientBeKind (@NetworkRailWAL) July 6, 2020
We are working hard to repair the bridge and make it available to run a normal service from Monday 3 August.
Thank you in advance for your understanding as we undertake this essential work. https://t.co/pxhHVlKq65
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