City commuters travelling to work via Moorgate station may be delayed this morning.
Great Northern train services into the station are subject to disruption because of an object caught on the overhead electric wires between Finsbury Park and Moorgate.
National Rail warned train services running to and from these stations may be delayed or revised. Disruption is expected until 9.30am.
"There is a reported problem with the overhead line equipment and Network Rail, who own and maintain the infrastructure, have staff attending to effect repairs," the rail operator said.
"Whilst this is ongoing, services may be delayed or subject to alteration. Once the fault is repaired, a normal timetable will be resumed as quickly as possible."
The routes affected are between Moorgate and the following:
- Gordon Hill
- Hertford North
- Welwyn Garden City
- Letchworth Garden City