A bus that says R1 Tunney's Pasture stops on a street outside a downtown mall in summer.

Until further notice, the Confederation Line will be served by a bus instead of the R1 along its length

The light rail line in Ottawa is closed until further notice because of a problem with how the trains connect to their wheels.

Monday around 5 p.m., OC Transpo said in a tweet that LRT service between Tunney’s Pasture and Blair stations had stopped and that all stations were closed because of a “technical issue.”

OC Transpo said Monday that the R1 replacement bus service is running along the length of LRT Line 1 until further notice. 

Renée Amilcar, the general manager of transit services for OC Transpo, said that replacement bus service would run every 10 minutes at the start of the day and every 5 minutes during peak times.

What’s happening

In two memos sent to the mayor and council members on Monday, Amilcar first said that a routine inspection found a problem with a bearing.

She later said that the inspector found more grease than should have been on one of the axles that connect the train’s wheels to its frame.

She wrote that when she looked at the axle again, she saw that “the bearing play was more than what it could handle and still work.”

Basically, these LRT wheels have bearings inside of them, which are part of what makes them roll and part of what connects the wheels to the train via their axles.

The inside of a train wheel with someone's hands inspecting it.

Amilcar said the decision to stop service was made “out of an abundance of caution” and that every axle on its light rail trains would be checked. Alstom, which makes trains, is also checking out the track.

Past problem

Amilcar said that the problem found on Monday is similar to problems that have happened before.

The Transportation Safety Board (TSB) says that when a train went off the tracks in August 2021, a “catastrophic bearing failure” caused a wheel to come off its axle.

In a letter to city officials in February 2023, the TSB said that the problems that led to the derailment in August 2021 and the failure of a part in July 2022 “continue to pose a risk to safety until the issues are resolved.”

At the LRT public inquiry, people said that there was a bigger problem: the way the wheel meets the rail on sharp curves puts too much stress on train parts, including the bearings.

In response to the TSB, Amilcar wrote to council in February that OC Transpo had already taken a number of steps to fix the problems.

As part of these measures, all light rail vehicles were checked every day and bearing assemblies were checked every 7,500 km.