Passengers on a train that derailed near Edgecliff Station on Wednesday afternoon after a bar broke through the floor of a carriage say it was making loud noises and emitting burning smells from the time it left Bondi Junction.

Kiriana Buffett was standing near the entrance to the carriage when the bar burst in, narrowly missing her head after she ducked underneath it.

"I just remember seeing it punch through the floor and then towards me – I don't know what happened next," said Ms Buffett, who sat in shock for 20 minutes after the incident. "Someone said it slowed down but I didn't see it go slow at any stage. I'm pretty lucky to be alive actually."

The chief executive of Sydney Trains, Howard Collins, said the bar that broke through the carriage was a piece of "metal channelling" attached to a concrete walkway near Edgecliff Station.