Ottawa’s LRT axis ‘probably failed’ hours before derailment on August 8: TSB – Ottawa | The Canadian News

A new report from the Transportation Safety Board of Canada (TSB) on the derailment of an Ottawa light rail on August 8 shows that part of the vehicle’s axle system overheated and melted before leaving the track that afternoon. .

TSB, the federal transportation watchdog, released a letter on monday investigating last month’s derailment on the Confederation Line, the first of two major incidents in recent weeks to shut down Ottawa’s LRT system.

On August 8, a train derailed near Tunney’s Pasture Station, taking the Confederation Line out of service for five days while crews worked to identify the problem.

Initial findings pointed to a gap in the axle bearing assembly on the affected train, leading to nine other vehicles receiving repairs on the same unit.

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Now, the TSB report shows that the train in question was experiencing problems earlier in the day that could have contributed to the derailment.

In the letter, sent to the Ottawa city manager by TSB’s director of pipeline and rail investigations, Paul Treboutat, the agency explains that a train axis “probably failed” around 1:25 pm that day. as the vehicle was traveling east between Cyrville and Blair Stations.

The vehicle experienced “multiple wheel slip warnings” during that time, according to a TSB review of the train’s records.

The agency’s timeline of events shows that after traveling back along the Confederation Line at 2:50 pm, “the train operator reported a burning smell” and parked the train on Tunney’s north platform. Pasture.

A technician arrived shortly after and found “burn marks” on a brake disc.

The affected brakes were isolated and the train was taken out of service until that night, but it was not inspected during that time, and technicians believed the problem had been identified.

Around 8:30 p.m. that night, after the brakes were repaired, the technician cleared the train to return to the maintenance and storage yard.

When the vehicle exited Tunney’s Pasture and switched from north to south track, “the train experienced an unusually rough ride” and derailed, at which point it came to a controlled stop, according to the TSB report.

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Crews inspect the damaged Confederation Line train east of Tunney’s Pasture Station on Monday, Aug. 9, 2021. Ten trains have been found to have similar problems.

Nick Westoll / Global News

The teams later discovered that one of the wheels was no longer attached to the axle.

The connection was severed, according to the TSB report, due to a “catastrophic roller bearing failure not previously detected.”

Roller bearings are part of the mechanism that connects the axle of the train to the wheels.

The images included in the TSB report show parts of these affected train roller bearings overheated and “melted” before derailment.

These rollers were later found on the track near the uOttawa station, suggesting that the bearing assemblies failed at some point when the train was heading west that afternoon, back toward Tunney’s Pasture.

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TSB notes that because the bearing assemblies are located inside the wheels, they are not accessible for visual inspection or the typical temperature gauges used to monitor the system.

“Consequently, an overheated roller bearing within the cartridge assembly can potentially catastrophically fail without being observed or detected. As demonstrated in this case, such failure can also lead to derailment if there is no intervention, ”the report reads.

TSB said the city had “considered” heat detection equipment during the design phase of the Alstom Citadis Spirit trains, “but it was not identified as a requirement because regular maintenance activities were deemed sufficient.”

But the August 8 derailment shows that regular maintenance and visual inspections “have proven insufficient to protect against such bearing failures,” according to the report.

TSB recommends that the city install such heat monitoring technology in Ottawa’s LRT vehicles in the future, but the federal watchdog can only make recommendations and is not mandated to oversee or approve remediation efforts after their reports. .

“The TSB would appreciate being informed about the measures that will be taken, if any, in this regard,” the report concludes.

Ottawa’s Confederation Line LRT remains inactive on Monday after the most recent derailment, with no timeline yet on when service is expected to resume.

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