Cable theft hits London and Herts commuter trains
Rail commuter services in Hertfordshire have been affected by the theft of overhead cables.
Trains to and from London's Liverpool Street station suffered delays after cables were targeted by thieves near Cheshunt.
Network Rail engineers are working to repair the damage.
British Transport Police said the incident was reported at 05.15 BST by a passing train driver who noticed a fire by the side of the line.
Officers called London firefighters and engineers from Network Rail who discovered about 4,000ft (1,200m) of copper cable had been stolen.
A British Transport Police spokesman said: "There is a common assumption that cable theft is a victimless crime, with the only effects being felt by the railway industry. This is not the case.
"Theft of cable can, and does, cause significant delays and cancellations to the rail industry - as well as costing the industry millions of pounds each year.
"What thieves don't realise is that they're attempting to steal cable, sometimes live, carrying up to 25,000 volts.
"Not only are they risking a court appearance, they're also risking their lives."