Passengers travelling on Greater Anglia services this morning are experiencing delays due to a fault with the signalling system.
Commuters heading into London from Suffolk and Essex are facing disruption because of a signalling problem between Norwich and Diss.
Trains have to run at a reduced speed which is creating delays of ten minutes or more.
Disruption is expected until at least 12pm today.
Customers holding advance purchase tickets can travel on alternative services if their designated train does not run, Greater Anglia bosses have said.
Engineers from Network Rail are working as fast as they can to identify the cause of the fault, they added.
It is affecting one signal on the London-bound line, and the team will be working throughout the morning to fix the fault.
Both Network Rail and Greater Anglia apologised to passengers for the disruption.
• Visit the rail operator’s JourneyCheck website to see if your train is affected.
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