Greater Anglia train services were part-suspended until at least midday this morning, after a person was hit by a train near to Southend Airport.
British Transport Police said they were en route to the station after receiving reports of a person under a train at around 8am this morning.
Greater Anglia said: "Due to emergency services dealing with an incident at Southend Airport, all lines are blocked. Train services running through this station may be cancelled, delayed by up to 60 minutes or revised."
Services from Southend into London Liverpool Street was among the lines affected.
Separately, Tube commuters were faced with disruption after a signal failure at Piccadilly Circus caused severe delays on the entire Bakerloo Line.