OC Transpo to begin testing short-term solution to axle-hub issues on O-Train

A single LRT train travelling on the western half of the Confederation Line Aug. 8, 2023 after three weeks without train service. (Leah Larocque/CTV News Ottawa)

OC Transpo and the Rideau Transit Group (RTG) will begin testing a short-term solution to the axle-hub issues on the O-Train later this month as the transit system continues to run at a reduced service.

In a presentation at Thursday's joint meeting of the Transit Commission and Light-Rail Subcommittee, OC Transpo said work has been ongoing toward a permanent solution to the axle issues which have plagued the Confederation Line since its 2019 opening.

RTG and Alstom have proposed placing a pin in the restraining nut on the axle hubs to prevent it from unscrewing. Adding pins will extend the useable life of the axle hub assemblies, which can work as a short-term solution before they are entirely replaced.

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Alstom is working on a long-term solution for the axle hub assembly issue with a redesign of the wheel hub assembly. Currently, all axle hub assemblies must be replaced every 60,000 kilometres and reduced service is running to limit travel on the trains.

The feasibility of the option has recently been explored and testing will be taking place in the coming weeks to collect data. OC Transpo and TRA, the independent company hired by OC Transpo following the derailment in Sept. 2021, will assess the results and determine if the full deployment across the network can proceed.

Richard Holder, manager of systems and operations integration for the City of Ottawa said the testing will occur in two main phases.

The first will involve an assessment of newer axle hubs, which have been provided to Alstom and will be retrofitted with the pins. Once the new axles are fitted, they will run selected trains on the line out of regular service with 1,500 kilometres of testing.

OC Transpo will then conduct a number of tests and measurements on the trains to ensure they are ready to be returned to regular service.

"We will be tracking every day the progress of that vehicle and we will make sure an operator reports back on any particular anomalies that they are experiencing with the vehicle." Holder said during the committee meeting.

The second phase of testing will involve OC Transpo testing trains with axles that have exceeded the 60,000 kilometres and applying the additional pins with 30,000 kilometres of testing over several weeks.

Alstom released pictures of the axle of an Ottawa LRT vehicle and the nut unlocking. (City of Ottawa/report)Staff say successful testing may allow for an increase in the number of double-car trains running along the O-Train line. Regular service on Line 1 will continue during the testing.

An update will be provided to council regarding the assessment of the testing. OC Transpo did not specify how long the testing phases would take.

In October, officials from OC Transpo, Rideau Transit Maintenance and Alstom delivered a report on the root cause review of the axle bearing issues on the O-Train vehicles since 2021.

There have been three major incidents related to the wheel hub and axle-bearing since August 2021, including a derailment of an LRT vehicle at Tunney's Pasture station. O-Train service was interrupted for 28 days in July and August after a routine inspection discovered excess grease on an axle hub assembly on one train.

Alstom has submitted several recommendations to Rideau Transit Maintenance for a sustainable solution to the issue, including moving the restraining rail, the deployment of top-of-rail friction modifier, ballast shoulders improvement and replacing the existing soft rail with harder rail.

Alstom says its root cause investigation found "higher than expected lateral loads" on the wheel hub assembly.