A person has been struck by a train on the line between Bristol and Devon, just south of Taunton, and all services on the route have been blocked.
National Rail has warned passengers to expect "major disruption" until at least 11pm this evening as emergency services continue working at the scene.
Great Western Railway (GWR) and Cross Country say passengers trying to get between Taunton and Exeter St Davids may have to cancel plans to travel or face long delays. Trains between these stations may be cancelled or delayed by up to 70 minutes.
A GWR spokesperson said: "A person has been struck by a train, leading to all lines being blocked. It is necessary to bring all trains in the affected area to an immediate stop.
"If you are onboard one of the services in this incident and have been affected by this incident or know someone else who needs support, there is always someone to talk to.
"Contact a Samaritan on 116 123 for free, any time, on any phone. Help is only a phone call away."
The firm says it is working alongside Network Rail to gather more information and understand how the incident will affect its services.
A spokesperson for Network Rail said: "The emergency services are currently dealing with an incident between Taunton and Exeter St Davids. So that they can safely carry out their work, all lines are closed.
"As a result, trains between these stations may be cancelled or delayed by up to 70 minutes. Major disruption is expected until 23:00."
Samaritans (116 123 in UK and Ireland) operates a 24-hour service available every day of the year. If you prefer to write down how you're feeling, or if you're worried about being overheard on the phone, you can email Samaritans at [email protected].
Person Struck by Train Blocks Rail Services Between Bristol and Devon