A man is in custody after he allegedly threatened a teen boy on a train with a knife.
The 17-year-old got on the citybound train at Killara in Sydney's North Shore around 9.15am on Sunday morning.
A short time later, a man entered the carriage and sat nearby. He then approached the boy and threatened with him a knife, police will say in court.
The boy got off the train at Milsons Point and contacted police.
The 37-year-old Terrey Hills man was arrested around 9.30am after a short foot chase.
Police found a knife hidden in his pants and a flick knife and scissors in his pockets.
The man has been charged and will appear at Central Local Court on Monday.
Australian Associated Press