Hijacked vehicles were placed on the rail line in Lurgan, County Armagh, on a second night of trouble in the town.
About 30 youths were involved in the disturbances during which two vans were hijacked and set alight along with a car stolen earlier at a GAA club.
Masked gunmen were again reported to have been seen in the area.
The disturbances followed the sentencing of three local men on Thursday over a dissident republican mortar bomb plot to murder police.
The railway line remains closed between Portadown and Lisburn.
Translink has advised that train passengers travelling on the cross border Enterprise service to Dublin will be bussed between Belfast and Newry.
Those passengers already faced delays to their journeys as there is still a bus substitution in place between Drogheda and Dublin due to a bridge collapse at Malahide last month.
However, Sinn Fein councillor Johnny McGibbon said the rioters had again failed in their attempts to create widespread disruption.
Two vans were hijacked and set alight at a railway crossing
"The majority of young republicans are not interested in this type of activity and have stayed away," he said.
"At this point the PSNI have not been dragged into confrontation in the area, and this is the sensible approach."
On Thursday night, at least five vehicles were hijacked during a night of violence, two of which were also set alight and abandoned on the nearby railway track.
Police carrying out a follow-up search at a property in the Kilwilkie area of the town on Friday recovered a replica gun.
Chief Inspector Jason Murphy said police had received numerous reports of armed men in the area on Thursday night.
"While there are no reports of any shots being fired, this is not acceptable behaviour for our streets and robust action will be taken," he said.
He said there were no reports of petrol bombs being thrown and no-one was injured.
"This was clearly an attempt to draw my officers into the situation to escalate the violence and to cause serious disruption or injury," he added.