The video was recorded on a phone by Stacey Eden, 23, who can be heard telling the older woman to stop disrespecting the Muslim woman who was with her husband and wearing a headscarf at the time.
Ms Eden, a pathology worker, told the ABC she was catching a train home to Mascot on the Airport Line at around 1:40pm on Wednesday afternoon.
She said she noticed a group of people enter the train, particularly a man and woman wearing a scarf with a baby.
At that point she said an old lady walked over and started speaking to them.
“I was just listening to my music,” Ms Eden said.
“The old lady actually bent over and touched the lady’s scarf while she was talking.
“I didn’t think anything of it.”
Verbal abuse made reference to Islamic State
Ms Eden said she noticed the old woman was verbally abusing the couple, who said nothing.
“The lady next to me was saying things like ‘all the people that were dying were because of the Muslims in the world and look what’s happening overseas’,” she said.
Photo: Stacey Eden intervened on a Sydney train when a Muslim woman was verbally abused. (Supplied: Facebook)
Ms Eden said the woman continued by saying: “Read the newspapers, why are you following this religion for, why do you wear things like that so you can marry a man who’s going to go marry a 6-year-old?”
“I was like ‘this isn’t right, why are you saying these kinds of things?'”
In the video, Ms Eden can be heard telling the old woman to leave the other woman’s dress alone.
“She wears it for herself, OK,” she said in the video.
“She wears it because she wants to be modest with her body, not because of people like you who are going to sit there and disrespect her.”
The older woman can be heard mentioning beheadings, the Sydney siege and suggesting the woman was an “ISIS supporter”.
Ms Eden said she got angry and started recording the incident.
“She was picking on her for the way she was dressed and that’s what really got to me,” she said.
“This lady that was sitting across from me wearing a scarf, she was minding her own business, she never said anything out of line, she never even spoke.
“That’s why I decided to say something because it just made me really angry and upset.”