Translink is offering up to £1k for any witness that can provide evidence pertaining to the assault of the worker
The public transport staff member was assaulted after a fight involving 40 people broke out at Castlerock train station.
A Translink spokesperson said: “We offer a reward of up to £1,000 for anyone who is prepared to provide evidence which leads to a conviction.
“We utterly condemn this incident, where a member of our staff was assaulted on the 5.38pm from Derry~Londonderry towards Belfast yesterday evening.
“The safety of our staff and passengers is our top priority. All our staff have the right to work without fear of abuse or violence and we are ensuring our colleague is offered all appropriate support.
“We are assisting the PSNI with their investigation, including provision of CCTV from the train, Castlerock station and body cam footage.”
Three people who were arrested in connection with the fight have been released, while two more have received community resolutions.
Police said the fight started onboard the train before spilling out on to the platform in the Co Londonderry village.
Five people were arrested following the altercation.
A woman (23) arrested on suspicion of assault occasioning actual bodily harm, has since been released unconditionally.
Another woman (64) arrested on suspicion of common assault, has further been released without charge.
A man (22) arrested on suspicion of common assault, has been released pending report to the Public Prosecution Service (PPS).
A man (30) arrested on suspicion of criminal damage and a woman (39) arrested on suspicion of common assault have been given a community resolution notice – an out-of-court disposal which does not appear on a criminal record.