Latest Line 1 wheel issue linked to overloading, expert says
Metal flaking in wheel assembly appears related to previous issues, according to expert
Priscilla Ki Sun Hwang · CBC News
Posted: Jan 22, 2026 6:22 PM EST | Last Updated: 2 hours ago
As the latest wheel assembly issues plaguing Ottawa's LRT system caused overcrowded trains and stations Thursday, an expert on those components says overloading is a factor — and despite what the city suggests — it appears related to previous wheel problems.
On Wednesday, OC Transpo said "spalling" — or metal flaking — was detected on several cartridge bearing assemblies. If not addressed, the spalling inside the axle bearing could cause cracks and eventual failure, the city said.
Those wheel bearings assemblies, which support the weight of the train, have failed before, causing a derailment in 2021 and forcing a lengthy LRT shutdown in 2023.
The latest defects are "separate" from the one that caused previous issues, according to Troy Charter, OC Transpo's interim general manager.
But an expert who specializes in the monitoring and diagnosis of bearing faults questioned that statement.
"As soon as I read the OC Transpo message, I had a little internal chuckle," said University of Ottawa professor Patrick Dumond.
"Now, it is a different issue, but I believe it's completely related to the previous issues we've had. They're both related to an overloading of these bearing cartridges."
The latest problem further indicates the trains are too heavy for the original cartridge bearing assemblies, Dumond said.
He referred to a previous instance where the nuts holding the bearings in the assembly were getting loose. There were suggestions from Alstom, the train maker, that forces from the rail tracks were overloading the assemblies.
"It's not just these rails that are causing overloading," Dumond said. "Because of the spalling, it's the average load of the train I think in continuous use that is too high for this setup."
<more>
https://www.cbc.ca/news/canada/ottawa/la...ked-to-overloading-expert-says-9.7056019