By Hannah Higgins, AAP
An off-duty police officer has been assaulted after intervening to stop a man allegedly choking a woman at a train station on NSW's Central Coast .
The man and the woman began arguing at Narara Railway Station about 9.50pm on Saturday, police say.
A short time later the man is alleged to have grabbed the woman and began choking her.
The off-duty officer stepped in to help after getting off a train.
However, the man allegedly resisted arrest and assaulted the senior constable, who wasn't injured.
A 19-year-old man faces a string of charges including assaulting police and choking and has been refused bail to appear at Gosford Local Court on Monday.