There will be no trains between West Hampstead and Bedford from 9pm this evening (Thursday) as work continues to repair overhead wires on the Thameslink route.
A replacement bus service will be in place calling at all stations.
An express bus service will run between St Pancras, St Albans and Luton Airport Parkway.
Keith Jipps from First Capital Connect said: “We are really sorry about the ongoing delays to our services and apologise to our passengers for the inconvenience caused.
“We are doing our best to help passengers continue their journey and are preparing travel plans for this evening, when Network Rail will complete the repair works, from 10pm.
“We urge passengers to check before they travel for the latest travel advice.“