A passenger has been taken ill at Brentwood station and as a result some lines are blocked.
Elizabeth line services may be cancelled, delayed by up to 10 minutes or revised to terminate and start back from Gidea Park.
Disruption is expected until 11:30.
Check before you travel:
You can check your journey using the National Rail Enquiries real-time Journey Planner.
Compensation:
You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.