The railway line between Belfast and Lurgan has been closed due to an ongoing alert.
Police are investigating a telephone warning received on Wednesday evening claiming that a bomb had been left on the tracks at Lurgan,
The investigation is focused on the Bells Row railway crossing at Antrim Road.
A bus service between Lisburn and Moira is operating for train passengers, and Translink said delays were expected.
Chief Inspector Paul Reid said the railway line would remain closed until the policing operation is completed.
“Motorists in Lurgan are advised that the crossing at Bells Row will also remain closed for some time and they should avoid the Antrim Road and Cornakinnegar Road areas until further notice,” he said.