Passengers using Abellio Greater Anglia services between Ipswich and Cambridge could face long delays this morning.
Damage to the overhead electric wires at Cambridge has blocked all lines running to and from the station.
Trains may be cancelled, delayed or revised at short notice, the rail operator has said, and disruption is expected until the end of the day.
Network Rail engineers are on the scene and all train movements have been stopped while they investigate the problem.
London-bound services running through Witham are also being disrupted this morning due to a signalling fault.
Main line trains are currently being delayed by up to 20 minutes in both directions.
Delays are expected to last until approximately 10am.
An Abellio Greater Anglia spokesman said: “We are sorry if your travel plans are affected by this disruption.”
For a full list of delayed and cancelled services, visit journeycheck.com/greateranglia
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