Greater Anglia trains from Norwich to London affected by Kelvedon wire damage
Regular trains are resuming after damage to overhead wires caused chaos for East of England commuters.
Disruption continued throughout the day on the Norwich to London Liverpool Street line due to problems at Kelvedon in Essex.
Abellio Greater Anglia said all lines have now reopened, but some delays will remain into the evening.
The company and Network Rail have apologised for the problems, saying the cause is being investigated.
Throughout the morning rush hour, people aired their frustrations on social media with many complaining about long queues for replacement buses.
Terri Harris tweeted: "Can't even get in the station at chelmsford... Platforms are empty!! #ridiculous". Adam Brown also tweeted: "The queue for a bus from Colchester. Approx 500 yards long. Absolutely disgusting."
Norwich North MP Chloe Smith, who was caught up in the disruption, said: "Many hundreds and indeed thousands of passengers are inconvenienced when delays like this happen.
"What we need is improvements on the line that will improve the reliability of it, although I think today's delay has yet to be fully diagnosed."
The Great Eastern Rail Campaign, made up of business leaders, MPs and members of the public, has been actively campaigning in the past few months for improvements to the line, which has been dogged with reliability issues for years.