The police have identified three teenagers involved in a train-surfing incident caught on camera in Lower Hutt early this month.
Footage posted on social media showed two young men clinging to the back of a train on the Hutt Valley line.
Constable Sarah Ferguson of the Hutt Valley Tactical Crime Unit said social media played a key role in identifying the three teenagers, and she warned the police would take any copycat incidents very seriously.
She said the police were committed to working with KiwiRail and the community to put a stop to such extreme recklessness.
The trio have been referred to Youth Aid, and KiwiRail Metro's General Manager David Shepherd said they were lucky to be alive after the stunt.
He said the company would work with Youth Aid on appropriate reparations for the incident.