A suspicious object was found on the railway lines at Finaghy Halt on the outskirts of the Belfast on Thursday afternoon.
Homes were evacuated while bomb disposal experts carried out a controlled explosion at the scene.
Police have not said what type of devices were found, but Alex Maskey MLA said officers told him there were at least two objects.
Residents have been told they can spend the night in the Lowe Memorial Church on the Upper Lisburn Road, where a Red Cross bus will be stationed.
Finaghy Road North is shut at its junction with Finaghy Park Central and Grangeville Gardens.
Road closures are also in place at Finaghy Road North at its junction with Ardmore Park South.
Homes were evacuated in Finaghy Road North, Finaghy Park Central, Finaghy Park North, Ardmore Avenue and Diamond Gardens.
The railway line remains closed between Lisburn and Great Victoria Street station in Belfast.
The alert caused havoc for rush hour commuters trying to leave Belfast on Thursday evening.
Trains to Lisburn, Dublin, Bangor, Larne and Newry suffered cancellations and delays, with replacement buses taking passengers to Lisburn.
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