Train lines were blocked due to a freight train fault.
Services running from London Liverpool Street through to Norwich were delayed on Saturday.
The fault occurred between Shenfield and Chelmsford, in Essex, Greater Anglia reports.
Trains were queueing while inspections take place on the freight train.
Great Anglia said on X: "We currently have no timescales for when we expect examinations of the freight train to be completed."
Liverpool Street to Braintree, Liverpool Street to Colchester Town, Liverpool Street to Clacton on Sea and Liverpool Street to Ipswich services were affected.
Greater Anglia updated its website to alert customers that there were no faults found after the investigation and the line has now re-opened.
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