This picture, taken by passenger Martin Stewart, shows the broken cable hanging over the track in Radlett station yesterday.
Severe delays have been predicted on Southeastern, East Midlands Trains and First Capital Connect until the end of the week.
More top news
£13 million pounds is being invested to help stop vulnerable young people being exploited by gangs who use them to sell drugs.
A drunk man who narrowly escaped death when he lay down between train tracks in Harlow has been given a 12-month community order.
A man from north London has been charged with the manslaughter of Louella Eve Fletcher-Michie, who died at the Bestival music festival.