The fundamental disagreement between the two major players in Ottawa’s Confederation Line LRT comes with the source of the excessive loads affecting the trains. Train manufacturer Alstom has concluded that excessive force on the vehicles is the root cause of failures on the axles that led to several issues on the line, including a derailment in August 2021.
However, Rideau Transit Group, the consortium that built and maintains the line, has questions about some of Alstom’s conclusions.
CEO Nicolas Truchon told a joint meeting of the Transit Commission and Light Rail Subcommittee on Friday that experts RTG hired to review Alstom’s conclusions identified “discrepancies” in the train-maker’s report.
“We need to get into the specifics and see what it is we need to change with the axle,” Truchon said. The cartridge bearing assembly, he said, does not generate the loads, it only suffers the loads, and there are still questions about the source of those loads.
This comes after a city report prepared for the meeting, which was made public last week, noted that Alstom had halted work on a previously announced redesign of the cartridge bearing assembly that holds the axles, which was touted last summer as a “permanent fix” to the axle-related problems. The City of Ottawa said it wrote to the company to urge it to resume work on the redesign immediately.
A source with knowledge of the situation who spoke to CTV News Ottawa on condition of anonymity because they couldn’t speak publicly told CTV News Ottawa Alstom paused it work on the redesign but has not cancelled it entirely. The reason for the pause is because of ongoing discussions with RTG. Alstom is a subcontractor of RTG.
Truchon effectively confirmed this Friday, saying the consortium still has questions about the nature of how the axles wear out. His report showed that some cartridge bearing assemblies show signs of wear at around 70,000 kilometres of use, while others can reach 400,000 km before the same issues arise. The other question revolves around how the assemblies on either end of the axle can have different wear patterns.
Alstom has said Ottawa is the only city in the world where it has encountered these issues with its trains.
RTG, however, says its experts, James Boyle Associates, came to a different conclusion.
“In summary, the Ottawa Confederation Line has no unique features and is currently maintained within the acceptable standards,” a presentation before the meeting said. “These standards are consistent with the standards for similar railroads, and nothing peculiar or unique could cause damage to trains using the line.”
Is it the wheels or the rails?
Last October, Alstom made nine recommendations toward a sustainable solution, including deploying top-of-rail lubrication, repositioning the restraining rails to avoid contact with the wheels, installing pins on the nuts that can come loose because of those lateral loads, and using stronger steel for the rails on the curves. Redesigning the cartridge bearing assembly was not one of the nine recommendations, but was considered an additional measure that could help. A full redesign would take upwards of two years to implement because of the extensive testing required.
The installation of the top-of-rail lubrication and the addition of nut pins on the vehicles are both in progress, while adjustments have already been made to the restraining rails. Replacing the rails with stronger steel, however, has not yet taken place. In addition to Alstom’s recommendations last fall, a recent report by the National Research Council of Canada also recommended high-strength rail on tight curves.
Truchon said harder rail is not out of the question, but it won’t affect the lateral loads Alstom identified as the root cause of the problems.
“If we replace the rail with harder rail, it will only reduce the wear rate. It’s not going to change lateral loads. It’s just going to create a change on the speed at which the rail is going to wear,” he said.
Truchon said there is no justification to replace any of the rails right now, but using harder steel could be an option when rail replacement arises naturally.
He also said the wheel component of the wheel-to-rail interface is also under review. Replacing the wheels on the trains is also easier than replacing the rails, he said.
Disagreement a source of frustration
Ottawa Mayor Mark Sutcliffe told reporters after Wednesday’s city council meeting that he is frustrated to see Alstom and RTG disagree on the root cause of the problems.
“I imagine that it’s not unusual when there are two large players involved in building a system of this nature, and when something goes wrong, that there’s disagreement on the root cause and that they will work it out over time,” Sutcliffe said. “Our relationship is with RTG and we’re holding them accountable for delivering the system that we paid for. So, it’s incumbent on those two parties to work it out, agree on the root cause, agree on the solution, and move forward on implementing it.”