Ottawa LRT derailment happened after hours of problems, TSB says

The Transportation Safety Board (TSB) of Canada says the city decided not to install a type of heat-detection equipment on light rail trains, which could have warned of problems on the train that derailed in August.

The TSB issued an advisory letter Monday as part of its investigation into a derailment of an out-of-service train near the western end of Ottawa's Confederation Line on the evening of Aug. 8.

The letter focuses on the bottoms of the two-vehicle trains, specifically the cartridge assemblies and large nut that attach the wheels to the axles.

Hours before the wheel derailed, the TSB says there was an axle failure on one vehicle that meant theoperator would have seen multiple wheel slip warnings at about 1:25 p.m. but they kept the train going.

After the train kept moving along the 13-stop line, the operator reported a burning smell at about 2:50 p.m. at its westernmost station, Tunney's Pasture.

Roller bearing parts found near uOttawa station around the middle of the linesuggest a cartridge assembly failed at some point during those 85 minutes and those parts fell off, according to the TSB.

Back at Tunney's Pasture, a technician found burn marks on a brake disk on one vehicle, misidentified the problem anddidn't check the train further, including the other vehicle.

From 8:15 p.m. to 8:25 p.m., technicians indicated the train moved smoothly back and forth on the tracks and cleared it to return to the maintenance yard, leaving the station at 8:30 p.m.

Almost immediately, two wheels derailed asit navigated a switch.

WATCH | August's LRT derailment:

Confederation Line closed after train axle leaves rail

3 years ago

Duration 0:32

A train was leaving Tunneys Pasture station over the weekend when one of its axles became dislodged from the rail, leading OC Transpo to close the entire line while officials investigate.

Wheel 'severed' due to bearing failure, TSB says

When workers went to put the train back on the tracks they discovered a wheel was no longer attached.

"The No. 3 wheel had severed from the axle due to a previously undetected catastrophic roller bearing failure and subsequent axle journal burn-off."

This derailment shut down the Confederation Line for almost a week as the fleet was inspected and nine other vehicles were found to have wheel problems.

• Bearing problem led to broken axle in Sunday's LRT derailment

The city is now more closely inspecting underneath its light rail trains, according to the TSB, which points out Via Rail trains have systems that can measure the heat inside its wheels to warn of potential problems.

The City of Ottawa decided against a similar system because it believed regular maintenancewould be sufficient.The TSB's letter said the city may want to reconsider this decision.

Without this system,the letter says "an overheated roller bearing within the cartridge assembly can potentially fail catastrophically without being observed or detected."

The city hasnot yet responded.

LRT currently shut down

The Confederation Line is currently shut down because another train derailed around Tremblay station Sept. 19. That too has triggered a TSB investigation, among other reactions.

No injuries were reported in either incident.

• Frustration building as transit users head into week 2 without LRT
• Critics question independence of LRT return-to-service review

An advisory letter is part of the report process when inspectors find something it should pass along, but it isnot the final report.

The regular 90-day timeline for these types of investigations would see the final report for August's derailment released in mid-November.