A teenage girl was allegedly indecently assaulted on a train at Macquarie Fields yesterday afternoon.
About 4.30pm on Sunday the girl boarded the train at Macquarie Fields station and was approached by a man.
He allegedly tried to speak to the girl before committing an act of indecency in front of her.
As she tried to leave, the man allegedly indecently assaulted her.
Police Transport Command officers are currently investigating the incident and would like to speak to a man who could assist with inquiries.
He is described as 170 centimetres tall, 15-20 years old with mousy brown hair.
He was last seen wearing a blue and white t-shirt, black tracksuit pants and black leather shoes.
Anyone with information is urged to come forward and contact police.