Emergency services are in attendance after a person was hit by a train near Witham station.
Train operator Greater Anglia reported the incident at 5.45pm this evening.
The line has been closed by police and disruptions are expected until 9pm, with journey times for passengers increasing by 80 minutes.
The incident is affecting all trains running between London Liverpool Street and Colchester.
A Greater Anglia spokesman said: "All train services were stopped earlier in the Witham area whilst emergency services attended to the incident. A rail replacement bus service has been running between Witham and Colchester."