National Rail has confirmed that cables were stolen from around Shenfield Station this morning (October 11) with the incident first reported at 5am.
This has caused the loss of signalling, preventing trains running between Shenfield, Romford and London.
Disruption is expected to last until “at least” 12.30pm.
All lines at Shenfield Station are blocked.
Trains running between London Liverpool Street and Shenfield may be cancelled.
National Rail has confirmed that response teams from Network Rail and British Transport Police are at the affected area, working on replacing the cables, but do not currently have an estimated time for when lines will re-open.
Elizabeth line services will run between Heathrow Airport / London Paddington and Gidea Park only.
Harold Wood, Brentwood and Shenfield will not be served.
Ticket restrictions for today have been lifted, and tickets will be accepted on Greater Anglia train services tomorrow (October 12).
A list of routes that will accept tickets at no extra costs has been released.
This includes: c2c between London Fenchurch Street / West Ham and Southend Central, Great Northern and Thameslink services between London Kings Cross, Cambridge and Ely and Central Connect buses on route 12 between Wickford and Billericay.
London Underground routes: included in the list are between Liverpool Street and London Kings Cross, on the Circle line between London Liverpool Street and Tower Hill (for London Fenchurch Street), on the Jubilee line between Stratford (London) and West Ham.
The British Transport Police has been contacted for further information.

