LRT tunnel inspection reveals pieces of concrete chipped from main slab, city says

The city's infrastructure department says pieces of concrete separated from the main slabcausing debris to fall along train tracks atSt-Laurent station which resulted in a partial shut down of the light rail train serviceanda tunnel safetyinspectionon Tuesday.

As of about 5 p.m., OC Transpo said light rail trains would be safe to begin running normally, after it hadsuspendedtrain service from Blair to Hurdman stations for most of the work day.

The interruption was necessary toconduct a "structural inspection" of the tunnel, the transit agency said.

In a memo to council, OC Transpo head Rene Amilcarsaid the safety inspection was initiated "out of an abundance of caution," and that there are no issues with any of the LRT trains or system.

Later in the afternoon, Amilcar said the inspection was complete and it is now"safe to resume service in the St-Laurent tunnel."

Amilcar said the city's infrastructure and water servicesdepartment wereinspecting the tunnels as it maintains the infrastructure.

'Delamination' issue caused chipping

The city's acting general manager for infrastructure, Carina Duclos, issued a memo late Tuesday eveningoutlining how staff responded to the concern.

Duclos said following a preliminary assessment, the department hired a structural engineering firm to conduct a detailed inspection of the tunnel area.

"Results from the inspection confirmed delamination," Duclos stated, explaining that means a "separation of the paste layer at the surface, creating an unbonded layer with the main slab."

With direction from the structural engineer, Duclos said,a contractor conducted "sounding and scaling" to remove small, concrete pieces that had separated from the main slab. That work wrapped up at about 4:15 p.m., she said, and the structural engineer report deemed that there were "no hazards" and it was safe to resume service.

Duclos goes on to explain that the St-Laurent bus station was constructed in the mid 1980s, and that it now houses both the LRT tracks in the tunnel below consisting of a "series of single span concrete rigid frame structures" and the upper levelplatform.

"Itis not uncommon to see delamination and scaling required in a structure of this age and with this level of complexity," she wrote.

The infrastructure department will conduct routine condition assessments of the structure in collaboration with OC Transpo, Duclos continued.

Replacement buses no longer running

Train service betweenHurdman and Blair stationshadbeen suspended since Tuesday morning for that "structural inspection" at St-Laurent station.

R1 replacement buses were running between Blair and Hurdmanstationsinstead of trains. There were also shuttles running connecting Cyrville to St-Laurent stations.

Shortly after 5 p.m., Amilcar said full train service is running regularly, and replacement buses will be wrapping up shortly.

A 2022 public inquiry found the Confederation Line was rushed into service to open in September 2019.

It's had multiple problems, including chronic axle problems that have caused derailments and led OC Transpo to scale back on the number of trains in service as it works on solutions.

Expansion to the east, west and south was originally supposed to be all done by 2023. None of those new lines have opened, with delays pushing them back to this spring, 2025 and 2026.