Problematic LRT train parts still pose 'risk to safety,' TSB says

The Transportation Safety Board is issuing a dire warning about the cartridge assembly in the axles on Ottawa's Confederation Line vehicles, saying they will "continue to pose a risk to safety" until OC Transpo and Rideau Transit Maintenance resolve the issues "to protect the travelling public."

In a Rail Safety Advisory issued to OC Transpo on Feb. 3, the federal agency says the cartridge assembly failures that caused two derailments in 2021 and a component failure last July "cannot be attributed to a single component", and the combination of the newly designed Alstom Citadis Spirit vehicle and the "more powerful drivetrain" are to blame.

The TSB letter also suggests the lack of an on-board heat detection system in the automated cartridge assembly is adding additional maintenance that is "labour intensive and time consuming for a component that should last over 1.2 million kilometres."

• READ the full Rail Transportation Safety Advisory Letter

In a memo announcing the TSB’s letter, the city’s head of transit services said the LRT system is safe

“RTG has provided the City with written confirmation that the O-Train Line 1 system is safe,” Renee Amilcar said. "After reviewing the letter, OC Transpo and RTG can confirm that all enhanced system safety measures in place align with TSB suggestions."

However, the TSB's letter suggests there is more work to be done to ensure the system is safe for riders.

On Wednesday, OC Transpo released the Rail Safety Advisory sent by the Transportation Safety Board on Feb. 3 regarding the vehicle axle bearing assemblies on O-Train vehicles. The TSB looked into the two derailments in August and September 2021, and the issue discovered with the wheel axle hub on a train last July.

"The City of Ottawa may wish to ensure that all parties involved in the OLRT undertaking work together to resolve design, operational, and maintenance risks to safety, as they emerge," the TSB said in a letter to the city.

"Furthermore, the parties involved should ensure that effective on-board monitoring systems for safety-critical LRV components, such as cartridge roller bearing assemblies, are put in place to protect the travelling public."

The cartridge assemblies are located inboard of the wheels on the LRT vehicle, and the wheels are secured to the exterior of each wheel hub by bolts to complete the bogie assembly. The cartridge assembly integrated the splined axle with the wheel assembly, which allows the wheels to turn.

The Aug. 8, 2021 derailment at Tunney's Pasture Station was due to an "undetected catastrophic roller bearing failure" in the axle bearing assembly, the TSB said. 

In September 2021, several weeks after that derailment, the agency recommended OC Transpo and RTM may want to ensure that it has heat detection systems in place to monitor temperatures of the cartridge roller bearing assembly to detect issues.

However, the TSB said this month "no concrete steps have been taken to resolve the safety deficiency identified" in that Rail Safety Advisory.

Last July, an O-Train driver reported a vehicle experienced "unusual vibration" while in operation.  An inspection identified that the axle hub was damaged "so severely that catastrophic failure was likely to occur had it remained in service", the TSB said. 

The Transportation Safety Board examined three cartridge assemblies from the failed axle wheel hub on the train that reported the issues last July.

"In summary, the 3 cartridge assemblies examined by the TSB exhibited numerous failure modes. The modes included fatigue fractures, rolling contact fatigue, surface wear, impact wear, environmental erosion, and frictional wear," the TSB said of its examination.

"The observed damage was widely spread throughout the cartridge assemblies and was not limited to any one particular component."

A failed axle hub taken from an LRT vehicle after it experienced unusual vibration on July 21, 2022. (TSB)

Rideau Transit Maintenance implemented several policies to address the situation, including daily inspections of all LRT vehicles prior to launch, inspections for bearing assembly free play every 7,500 km and replacing axles after 175,000 km.  Temporary speed reductions are in place at several locations along the 12.5 km route.

"Since OLRT LRVs have no on-board automated cartridge assembly heat detection system, the free play inspections continue to be necessary," the TSB said. "However, this additional maintenance task is labour intensive and time consuming for a component that should last over 1.2 million km."

In its letter to the city, the TSB notes the Alstom Citadis Spirit LRV built for Ottawa has had numerous reliability issues, while other Alstom trains built around the world have had few reliability issues.

"To date, there have been 2 serious main-track derailments and a near catastrophic component failure that all involve OLRT LRV cartridge assemblies," the TSB said in the Feb. 3 letter.

"While the materials used to manufacture the cartridge assemblies conformed to the manufacturer’s specifications, the 3 cartridge assemblies examined by the TSB exhibited numerous failure modes. The observed damage was widely spread throughout the assemblies and was not limited to any one particular component."

The TSB says in the three cases cited, the root cause of the cartridge assembly failures cannot be attributed to a single component.

"It is likely that the combination of the newly designed LRV, new Iponam bogies, and a more powerful drivetrain may play a role in the failure of cartridge assemblies,' the TSB said.

O-Train is safe, city says

In a memo to Council, Amilcar says Rideau Transit Group has provided the city with "written confirmation" that the O-Train is safe.

• READ the full memo from Renée Amilcar to Ottawa mayor and members of council

"After reviewing the letter, OC Transpo and RTG can confirm that all enhanced system safety measures in place align with TSB suggestions," Amilcar said in a memo Wednesday.

The enhanced mitigation measures in place to ensure the trains are safe include:

• Rideau Transit Maintenance (RTM) inspects all light rail vehicles daily, prior to every launch
• All leading and trailing bogie axles are replaced when they reach 175,000 km of service and are inspected for bearing assembly free play every 7,500 km
• The remaining axles are inspected at every 3,750 km when they exceed 175,000 km
• Temporary Speed Restrictions are in place at several locations along the alignment
• OC Transpo hosts weekly status meetings on the root cause analysis with RTG, RTM, OLRT-C and its subcontractors

Amilcar says staff are reviewing TSB's findings in detail, and the letter will assist OC Transpo and Rideau Transit Maintenance/Rideau Transit Group in completing the final root cause analysis into the wheel axle hub assembly issue.

"RTG has installed vibration monitoring equipment on some trains and plans to expand the installation on additional vehicles in the coming months," Amilcar said.

Coun. Riley Brockington called on OC Transpo to ensure the system is safe following the release of the TSB letter. Ottawa's director of engineering services tells CTV News Ottawa the "system is safe" for riders.

"If we had any doubts about the safety of the system then we would not be running operations," Richard Holder said Wednesday afternoon, adding Alstom has sent a letter indicating the system is safe.

Holder says OC Transpo and Rideau Transit Maintenance have a containment plan in place to ensure safety on the system.

"Regular inspections of the axle bearing assembly and we also have a program of speed restrictions that are in place, so with those mitigations in place then we don't have doubts about the safety of the system," Holder said.

Former City Manager Steve Kanellkaos directed Rideau Transit Group to explore the idea of adding heat detectors on the trains in September 2021.

"As noted in the TSB letter, the arrangement of bearings precludes effective visual inspection and temperatures cannot be monitored by traditional wayside hot bearing detectors (heat detection units mounted at track level)," Kanellakos said in a memo on Sept. 28, 2021.

OC Transpo has installed vibration monitors on the axles of 10 vehicles as part of a pilot project.

"We are now at the point of being able to have more confidence about that proof of concept of that technology, so we're expanding the implementation to another 10 vehicles that is expected within a few weeks and then ultimately we're looking at expanding the vibration monitoring to the whole fleet," Holder said.

Holder says OC Transpo and Rideau Transit Maintenance looked into heat detection technology for the LRT vehicles, but "the indications were that there was not appropriate technology that is available".

"We are now continuing our efforts to find an appropriate technology."

Mayor Mark Sutcliffe declined an interview with CTV News Ottawa. In a statement, Sutcliffe said "safety is the highest priority" at OC Transpo.

"If there were concerns that train service was not safe to run, the City would pause service immediately," Sutcliffe said Wednesday evening.

"OC Transpo has already undertaken the mitigation strategies suggested by the Transportation Safety Board to ensure that, while a permanent solution is implemented, the service remains safe. These measures include inspecting vehicles daily, inspecting and replacing axles at regular intervals, continuing speed restrictions at several locations, utilizing vibration monitoring equipment, and meeting regularly with RTG and subcontractors on mitigation and permanent solutions."