Passengers were forced to walk down tracks and commuters have faced massive delays in the cold.
There's been more than 24hours of chaos on trains coming into and out of London.
The problems were caused yesterday afternoon - after overhead cables were damaged in Hertfordshire.
Services in and out of King's Cross were affected and rail lines around Hitchin had to be shut.
First Capital Connect released this statement about the revised timetable today on the Great Northern route:
For more information visit the First Capital Connect website.