Woman's wrist broken in NSW train attack

A woman had her wrist broken in an assault on a train on the NSW Central Coast.

The 21-year-old woman and her 25-year-old female friend boarded a north-bound train at Gosford just after 3am on Sunday, and they were followed into their carriage by three men.

Police have been told one of the men first splashed drink from a can onto the women.

"He then grabbed the younger woman's hands, applying extreme pressure and breaking a bone in her wrist," according to a NSW Police statement.

"The man also pushed her down into a seat."

The older woman ran and pressed the emergency button, stopping the train at Narara.

The men had fled by the time officers from Police Transport Command made it to the carriage.

The injured woman was taken to Gosford Hospital for treatment.

Her attacker is described as caucasian, aged early to mid-20s, with a stocky build, and messy, shoulder-length, brown and sun-bleached hair.