The railway line between Crosskeys and Ebbw Vale is still closed because of a landslip brought on by Storm Dennis.
The landslip at Aberbeeg has also closed the A4046 road.
Network Rail engineers expect the line to be reopened tomorrow, but Transport for Wales is urging commuters to check its website before they travel.
Transport for Wales’ Customer Delivery Director, Bethan Jelfs said: “As a result of rail and road infrastructure damage and continued flooding caused by Storm Dennis, and a weather warning for further heavy rain this week we are still strongly advising all customers to check their journey arrangements prior to travel and allow plenty of time.
“The situation is changing all the time and with further weather warnings of heavy rain on Wednesday and Thursday we strongly advise customers to check for regular updates before the Wales v France Six Nations rugby international in Cardiff on Saturday February 22.
“The rail network is significantly damaged in places and with limited replacement road transport available to us it’s inevitable that some services will be subject to 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 rail replacement bus service wherever possible, however with continued flooding and damage to a number of roads, journeys may take significantly longer than is usual on many routes.”