The two teens involved in the incident were doing okay, though de Montalk suspected the full impact of events had yet to sink in.
The mother said "it hurt" to watch graphic video of her daughter being abused and she remained disappointed that other train users did not intervene.
The victims were travelling from Britomart to Avondale when five men, dressed in Four Square costumes, attacked the teens. The men are believed to have been travelling to the Auckland Darts Masters competition at the Trusts Arena in Henderson.
"The kids were on the train near them and one of the men started walking around and telling my daughter to put her hand in his pouch, because he was wearing an apron," de Montalk said.
"He then . . . exposed himself to her.
"Then one of the other guys suddenly took a disliking to the boy she was with. He called him a faggot, rolled up his sleeves and started choking him."
Police today described the incident as a "completely unprovoked attack".
"The two men who are assisting us with our inquiries came forward yesterday, and we have identified a further three men and are yet to speak with them," said Detective Senior Sergeant Marcia Murray.
No charges have been laid and inquiries are continuing.
Meanwhile, Auckland Transport acting media relations manager James Ireland said AT was investigating the "extremely disturbing" attack as a matter of urgency.
"This event is extremely disturbing and we know it was very upsetting for the young people involved.
"We are sourcing CCTV to review and send to the police. We will work with the police in any way we can."
