OTTAWA -- Service on the Confederation Line LRT will remain suspended until at least Friday, according to OC Transpo, following a minor derailment Sunday evening.

Service was suspended Monday after the wheels of one of a train's 10 axles left the track as it was leaving Tunney's Pasture Station. The train had no passengers on board, remained upright, and there were no injuries reported.

In a memo Monday evening, OC Transpo General Manager John Manconi said the investigation into the incident is focused on the axle bearing and every train must be inspected, a process that takes several hours per train. As a result, he said OC Transpo is targeting a return to LRT service that is "adequate to meet current ridership levels on Friday or Saturday of this week."

In another memo on Tuesday, Manconi said the stopped train will likely be moved Wednesday. Specialized equipment is required to move the train without causing any damage.

"The movement of the train needs to be planned and managed carefully in order to ensure the weight of the train is distributed evenly and the vehicle can be moved without damage to it or other rail infrastructure," Manconi wrote. "Once these preparations are complete, the train is expected to be moved back to the (maintenance and storage facility) tomorrow."

The Transportation Safety Board of Canada (TSB) announced Monday that it had sent a team of investigators to the scene.

In a statement to CTV News Ottawa on Monday, the TSB said it was told one of the train's wheels derailed while crossing tracks, which damaged one of the switches on the line.

"At 8:34 p.m., 8 August 2021, an empty two-car Light Rail Transit O-Train was crossing from track 1 to track 2 at Tunney’s Pasture when one wheel on the one of the cars derailed on a switch. The train remained upright. There were no injuries and no dangerous goods involved. The switch was damaged," the statement said.

Manconi said that the scope of the TSB's role as it relates to this incident is still being determined.

Rideau Transit Maintenance (RTM), which maintains the Confederation Line, is searching for the root cause of the initial incident on Sunday, Manconi said.

"Once the train involved in the incident is returned to the (maintenance and storage facility), the affected axle bearing assembly will be disassembled in order to do a detailed review."

Director of Transit Operations Troy Charter told CTV News Ottawa in an interview on Tuesday that he is confident RTM will get to the bottom of this latest incident.

"We’ve had good reliability for the past year. That, to me, is indicative of--we’re getting through those growing pains and RTM is stepping up and investing the time and effort and resources and correcting those issues that plagued us the first 16 months of service," he said.

Reliability on the LRT prior to this incident was as high as 99 per cent over the past 12 months, Charter said; however, the Confederation Line has also been operating well below capacity since March 2020, when the COVID-19 pandemic began. OC Transpo said Monday that ridership across the transit system was at 30 per cent of pre-pandemic levels in July, noting that it had been below 20 per cent earlier in the year during stay-at-home orders and lockdowns.

Charter said a return to service by Friday or Saturday would be dependent on the investigation into root cause of Sunday's incident and the results of the inspections on the train cars.

R1 bus service has replaced the LRT between Tunney's Pasture and Blair stations. Manconi said OC Transpo staff are monitoring ridership and will make adjustments to service as needed to meet ridership levels.

No cost to city

A brief statement from Manconi, sent late Tuesday afternoon, said the ongoing closure of the Confederation Line would not affect city taxpayers.

"The current O-Train Line 1 suspension of service will have no cost to the City of Ottawa," the statement said. "Rideau Transit Maintenance's (RTM’s) monthly payment is calculated based on several factors including vehicle availability, station availability, kilometres travelled and other indicators. As a result of this current service suspension, deductions from RTM’s monthly payment will be significant. While the current Line 1 service suspension continues, the total amount of deductions is yet to be finalized."