Some rail commuters are facing delays of up to 90 minutes this morning.
Yesterday, major damage to overhead wires was reported.
That affected Southeastern, East Midlands Trains and First Capital Connect services.
Network Rail are reporting that trains are currently unable to run between Luton Airport Parkway and West Hampstead.
First Capital Connect has said there are delays on trains out of Bedford and Luton of up to 90 minutes.
Delays of up to an hour are also reported on East Midlands trains between Corby and St Pancras.
There are some bus replacement services in place.
Overhead line problems have again brought rail delays in the Northampton and Milton Keynes areas.
Thousands of train passengers are potentially facing severe delays until the end of the week due to "extensive" damage to power cables.