Rail customers should expect "significant" service delays and cancellations with lines closed due to flooding, says Transport for Wales.

Customers are urged to check before they travel and allow extra time for their journey today following flood damage to key routes caused by Storm Dennis

Transport for Wales’ Customer Delivery Director, Bethan Jelfs and Chris Pearce, Head of Operations, Network Rail Wales and Borders said: “As a result of flooding caused by Storm Dennis over the past 48 hours, Transport for Wales and Network Rail are strongly advising all customers to check their journey arrangements prior to travel today (Monday 17 February) and allow plenty of time to their journey.

“Customers are also advised to expect significant delays on certain parts of the network following further heavy rainfall overnight and, if possible make alternative travel arrangements.

“There has been damage to the rail network and with some roads remaining impassable and limited replacement road transport available, it is inevitable that some services this morning will be subject to significant disruption which will result in delays and cancellations.

“Where trains are cancelled or terminating short of destination, every effort will be made to provide a replacement road transport wherever possible."

As of 7am on Monday, February 17, the following lines are closed and customers are being strongly advised not to travel unless absolutely necessary on these routes, where many roads are impassable so replacement bus transport unable to make the journey.

Cambrian Line
A rail replacement bus service will operate from Welshpool to Aberystwyth and between Machynlleth to Pwllheli. 

On Monday afternoon, Transport for Wales said: "Due to road conditions road transport has been suspended through Shrewsbury. Buses will run between Welshpool and Aberystwyth."

High-water levels were reported in rivers on the route over the weekend with flooding on the railway reported at some locations - key structures including Black Bridge and the viaduct are due to be inspected this morning as water levels have started to recede.

The Cambrian Coast Line was severly impacted by Storm Ciara, although good progress was made last week on the repair of the line - if will be reassessed following Storm Dennis before we are able to confirm timescales for reopening.

Network Rail is working towards reopening the line between Shrewsbury and Machynlleth later today and may be able to reopen the line towards Aberystwyth, subject to further inspections.

The line between Shrewsbury and Machynlleth is expected to remain closed until 6pm.

Heart of Wales Line
Line between Shrewsbury and Llandrindod Wells remains closed due to flooding caused by a culvert blocked. Network Rail is working towards reopening the line by close of play today. 

Newport to Hereford
Services on the Marches line will be replaced by a road replacement service due to flooding. Line remains closed following a significant ballast washout at Pontrilas between Abergavenny and Hereford.

Cardiff Valley Lines
Flooding north of Pontypridd has cut off services to Porth, Aberdare and Merthyr to Tydfil due to flooding at Trehafod.

Ebbw Vale Town
Crosskeys line is closed due to a landslip.

Conwy Valley
A rail replacement bus service will operate between Llandudno Junction and Blaenau Ffestiniog.

Transport for Wales added: “The safety of our customers and colleagues is our absolute priority and we are working closely together to minimise any disruption by doing all we can to keep our customers moving and informed.

“The situation is changing all the time and therefore services are likely to be disrupted throughout today with last minute alterations. We would like to thank customers in advance for their understanding.”

Customers are advised to check their journey before travelling on nationalrail.co.uk or journeycheck.com/tfwrail/