Engineering work is taking place between London Liverpool Street and Shenfield, closing some lines.
Until 09:45 on Sunday morning, and from 23:05 until the end of service on Sunday evening, trains between London Liverpool Street and Shenfield will have journey times extended by up to 15 minutes, with services departing up to 15 minutes earlier than usual.
Check before you travel:
You can plan your journey using the National Rail Enquiries Journey Planner.