Emergency services were called to a train station in Newtownabbey last night (Friday) after a passenger took ill.
Police said they received a report that a female had collapsed on a train which had stopped at Mossley West at around 6.10pm.
A PSNI spokesperson said: “Upon police arrival a large number of people, many of whom were teenagers, were asked to leave the train to facilitate treatment of the collapsed female by ambulance staff.
“A small number of other people were found to be suffering ill effects of drink or drugs and were also treated.
“A total of four people were transferred to hospital and NIR staff arranged for a large number of young people from the train to complete their journey to Belfast via bus transfer. Other passengers were able to return to the train and complete their journey.”
Police added they also seized a small quantity of suspected drugs.