Railway services between Portadown and Lisburn were suspended twice on Sunday as police dealt with reports of an explosive device having been left near the train line at Lake Street in Lurgan.
The first PSNI operation began shortly after 10am resulting in rail passengers being bussed between the two stations.
The all-clear was given just before mid-day, but police were back at the scene two hours later and the line was closed as police began a fresh search.
Lurgan DUP councillor Carla Lockhart said the actions of those responsible for the alerts were “tarnishing the good name of Lurgan” and “ill thought out”.
She said: “This is the third time within a matter of months. It is wearing thin with the local people.
“I would call on the PSNI to continue their efforts to thwart the plans of those who seek to disrupt. We also need the public right across Lurgan to bring any information they have to the police.
“It is vital that any information is passed to the PSNI to help bring these individuals before the courts.
“I met with the PSNI last week to discuss dissident activity and will be following up with a further discussion this week to ensure sufficient resources are available to tackle this ongoing threat.”