Iarnród Éireann is investigating the leaking of CCTV footage showing a woman falling under a train during an alleged violent disorder incident in Dublin last month.
Footage of the incident shows the woman hurrying to catch the train before a youth lunges at her.
A second youth then pushes his bike towards her before she falls towards the tracks.
The woman was rescued by onlookers before the train began to move off.
Three teenagers - one aged 13 and two aged 16 - were last week arrested by Gardaí investigating the incident.
Iarnród Éireann has now opened an investigation into how the footage was leaked and shared on social media.
“Customers have a right to expect that station CCTV is used for their safety and security and to assist investigations, not to be distributed in an unauthorised manner,” said a spokesperson.
“While our foremost priority is to assist the Gardaí in ensuring those responsible are brought to justice, we are also investigating the unauthorised distribution of this footage and have reported the matter to the Data Protection Commissioner.”
The incident has led to calls for increased security on the Dublin DART line.