Montreal Metro's Green line shut down after cracks detected in tunnel ceiling

Montreal Metro's Green line is closed between Lionel-Groulx and Frontenac stations for an indefinite period after a water leak led to the detection of cracks in the tunnel's vaulted ceiling that are a cause of concern.

The service was shut down just as the afternoon rush hour was getting into full swing Monday, forcing passengers to find other ways home as the Société de transport de Montréal (STM) scrambled to evacuate stations and get shuttle buses into place.

The water leak allowed the engineering team to detect the cracks between Berri-UQAM and Saint-Laurent stations, the STM says in a news release.

"As STM's priority is to ensure the safety of its employees and customers, the company has requested the City of Montreal to redirect heavy vehicle traffic between Berri and Saint-Laurent streets," the release says.

The STM has also decided to cease Metro service between Lionel-Groulx and Frontenac stations until further notice, so that teams can further evaluate the situation, the release says.

A first message published on Twitter by the STM announced that the resumption of service was scheduled for 2 a.m.

The STM then corrected that tweet just before 5 p.m., indicating in a subsequent message that the service interruption would be for an indefinite period.

To mitigate the impact on customers during this exceptional closure, the STM is providing a temporary bus shuttle service that will run continuously from 5 p.m. until the last train passes between Berri-UQAM and Frontenac stations, the STM says.

The STM suggests passengers use the Orange line to travel between Lionel-Groulx and Berri-UQAM stations.

"STM personnel will be positioned at strategic locations in the stations to direct customers to the Orange line and temporary surface service," said the agency.