A train heading northwards on the Larne line stopped just short of Whiteabbey station after an incident unfolded at around 1pm on Friday.
The train short of the platform on the Belfast side, then proceeded to the platform.
It stopped for roughly half an hour.
The nature of what happened was unclear.
Translink initially said on its Twitter feed that the train had been delayed for “operational reasons”.
A spokeswoman for Translink then said that a member of the public was said to have been in distress.
They said a person had been on the tracks, but that they had not been struck by a train.
Both police and ambulance were called to the station.
Asked for details, the PSNI said: “Police responded to a report of concern for safety for a vulnerable female in the Station Road area of Whiteabbey at approximately 1.10pm today.
“The female was located and subsequently taken to hospital.
“There are no further details.”