A signalling fault at Diss is causing delays on the Norwich to London railway line.
Engineers are currently at the scene investigating the fault, with delays currently of 5 minutes in both directions.
Delays are expected to continue until 8pm tonight.
The fault is believed to have happened at around 11.30am.
For the latest rail updates, see www.abelliogreateranglia.co.uk or follow @GreaterAnglia on Twitter.