THE man who stopped a woman allegedly threatening Sydney train passengers with a chisel did so with a “UFC” move he learned in jail.

The former inmate, known only by his first name Tarek, told Channel Seven he had to do something because people were terrified.

“The fear was in people’s eyes, I could see it. And I thought ‘you know what? No one’s doing nothing, I’m going to react’,” Tarek told Seven.

And he revealed he learned the move that stopped the woman while he was behind bars when he was learning how to defend himself.

“I just did a bit of UFC on her.”

The Boxing Day incident began after the woman reacted angrily to a man sitting in the same aisle as her as their train headed out of Campsie on the Bankstown line.

Mobile phone footage showed her walking towards the man with the weapon yelling “I’ll stab you, dog”, before Tarek tackles her onto the train seat and she drops the chisel.

The woman, 19, was charged yesterday afternoon with assault and being armed with the intention of committing an indictable offence. She is expected to face Downing Centre Local Court in February.

Her partner told Channel Seven she was carrying a chisel because she was on her way to a relative’s house to help fix a door.

While officers initially spoke to her immediately after the fracas, the 19-year-old from Waterloo in the city’s south was then taken to hospital for treatment for a medical condition.

The woman can be seen on the footage pushing past the man and yelling abuse as she walks angrily out of the carriage away from him.

The man got angry with her abuse and responded to her. The footage then shows her saying to him “you can’t sit next to a woman” as she turns around and begins advancing towards him with a chisel in her hand.

As she is doing so she is heard yelling: “I’ll stab you, dog” and made stabbing motions with her arm.

She also asked the man, who was Chinese, “do you even speak English?”

A young man then tackled her and forced her to drop the chisel. Police and paramedics boarded the train when it stopped at Canterbury train station about midday.

Witness Annie Huang, 22, told Fairfax the man who disarmed the chisel-wielding woman intervened because the Chinese man had done nothing wrong.

“He said that the Chinese man did nothing wrong. All he did was sit on the seat, and didn’t even sit right next to the lady, and the lady just started yelling at him. He knew he had to do something,” Miss Huang said.

A NSW Police spokeswoman told news.com.au they were investigating the incident and asked witnesses to come forward.

“Police from Ashfield Local Area Command are investigating the incident and are appealing for anyone who witnessed it, or the events that lead up to it, to come forward.”

Police said several people involved in the incident have been spoken to by police and witness statements are being compiled.