Green Line service restored, tunnel deemed safe: STM

The STM has resumed regular service on the Green Line after overnight inspections determined the damage discovered on the tunnel was 'superficial.'

The STM has resumed regular service on the Green Line after overnight inspections determined the damage discovered on the tunnel was "superficial."

"After more than six hours of inspection, hammering and observation, the degradation of the concrete is superficial, and the integrity of the vault is not in question," said STM spokesperson Justine Lord-Dufour in a statement. 

"The work allowed the removal of surface concrete that could have fallen," she continued. "As a result, the STM can safely resume service."

A tweet from the STM around 5 p.m. Monday said it shut down the line between Lionel Groulx and Frontenac for an "indefinite period" but did not explain why. A previous post said service would resume at 2 a.m.

Shortly after, it clarified that a water leak had made it possible to detect cracks in the vaulted ceiling of the tunnel between the Berri-UQAM and Saint-Laurent stations following an assessment by its engineering team.

STM CEO Marie-Claude Leonard says unusual water infiltration was being monitored throughout the day.

Workers weren’t sure if it was caused by crumbling concrete or was part of a larger crack that would pose a safety threat, she said, calling the decision to close the stations a precautionary measure.