A commuter claims hundreds had no power, heat, lights or toilet facilities, as they waited for five hours to be rescued from a broken down train.

Usha Sundaram, associate professor of the Norwich Business School at the University of East Anglia, was on her way to a conference when the 7.40am train broke down at Forest Gate at 9.25am on Tuesday.

Greater Anglia apologised for the delays and that a specialist team has been sent to investigate the issue.

The professor said she does not believe it was a power failure, as claimed, as she watched the train's computers be rebooted over several hours.

Professor Sundaram, who is also associate dean for the Social Sciences Faculty, said: "The fault was not a power failure as was reported.

"We could see the computer reboot on the fancy new display screens inside the train but after about half an hour they made an announcement they were shutting down the power to help with the train reset."

Read more: Passengers stuck on-board for more than three hours as new Greater Anglia train breaks downFor the next few hours, she claimed attempts were made to reset the train which gradually lost power, heat, lights and toilet facilities.

The professor added: "Only one toilet was working but we couldn't get into it as the doors wouldn't automatically open because of the lack of power."

Food and water also ran out onboard as people awaited the first rescue train which had been sent to tow the train to Shenfield.

The plan was unsuccessful and passengers were told another train would pull up alongside to allow passengers to cross across a board or ladder - but the train doors would not align.

At around 2pm evacuation began with those on board asked to remove heavy bags and high heel shoes as they left via a wooden ladder, on to the tracks to a new train.

Read more: Old train rescues 450 people stranded on new Greater Anglia trainThey eventually arrived in London sometime before 3pm where a train was provided to take them back to Norwich.

The professor praised the train's staff, Network Rail Team and British Transport Police for reassuring passengers during the incident.

A Greater Anglia spokesperson said it tried to keep customers comfortable by giving them all of the food and drinks from the café bar.

She added: "We apologise sincerely to passengers who were travelling on the Intercity train which broke down on Tuesday morning.

"We are still investigating all aspects of the incident to try to prevent any similar problems in the future. Customers affected have been informed how to claim compensation for their delay.

"We are working closely with Stadler to improve the reliability of our new trains. They have dispatched a specialist team of engineers from Switzerland to assist us with this issue."