A university professor screamed as she was fatally hurt on a railway station's moving walkway, a court heard.
Professor Sally Baldwin: Killed on walkway
Sociology lecturer Sally Baldwin, 62, from York, suffered horrific injuries after falling into the machine's mechanism in October 2003.
A worker who tried to help her at Rome's Tiburtina station sobbed as he described the incident to the city's central criminal court on Wednesday.
Three maintenance firm directors face manslaughter and negligence charges.
Domenico Leti, 71, and the two managers in charge of maintenance operations, Leonardo Casali, 32, and Luana Lepore, 28, were charged after the accident.
Rail worker Vincenzo Pratico tried to save Ms Baldwin but he was also left injured.
Mr Pratico, still on crutches, told the court he knew something was wrong when he heard a piercing scream.
He said: "I heard a loud scream and I knew instantly something terrible had happened I turned around and saw the lady had fallen through a hole in the walkway.
"I remember shouting at people to press the stop button and they did but nothing happened it just kept moving all the time."
Paramedics tend to a man seriously injured by the collapsed walkway
In tears, he added: "I feel so guilty about not being able to do any more to save her but I couldn't. I tried my best but there was nothing I could do."
He said he was still unable to walk properly because of the injuries he suffered.
"Ever since that day I have had nightmares, I can't sleep at night. I always think about the woman who I saw die in front of my eyes.
"But there was nothing I could do to save her. I'm not Superman but I tried all I could. The power of the machine was just too strong for me.
"I tried to stop it with my bare hands and broke my wrist then as I tried to pull her I was also dragged in and had my leg caught. The pain was so intense."
Ms Baldwin had moved from Scotland to York after divorcing her husband Jack of 30 years.
She had planned to celebrate her birthday with him and another friend in Italy when the tragedy occurred.
Mr Baldwin, 64, an antique book dealer, was standing in front of his former wife on the walkway when she fell to her death.
The trial was adjourned until next month.