POLICE have arrested a Noble Park girl, 17, over a robbery on a train on 27 October.
They said she and a boy approached a man, 18, on a Pakenham-bound train about 1.30am.
They allegedly demanded his phone and threatened to assault him so he handed over the device.
The victim informed protective services officers (PSOs) at Noble Park Railway Station of the incident and a short time later police arrested the girl and recovered the phone.
A Cranbourne boy, 17, is assisting police with further inquiries.