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TSB told Ottawa LRT contractor to speed up wheel swap after more cracks discovered
The TSB in early November suggested that work be sped up to remove wheels with the problematic screws.Author of the article:
Jon Willing
Publishing date:
Dec 15, 2020 • Last Updated 2 hours ago • 3 minute read
A view of a mounted wheel showing 12 lug nuts, three jacking screws (circles) and four grounding cables. One jacking screw is obscured by a grounding cable. PHOTO BY TSB /TSB
The Transportation Safety Board on Tuesday provided details about an investigation into cracked wheels on Ottawa LRT vehicles, with the agency confirming that a protruding jacking screw on the wheel hub was the possible cause, and revealing a quirk in how the wheels were provided for installation.
The TSB in early November suggested that work be sped up to remove wheels with the problematic screws.
TSB told Ottawa LRT contractor to speed up wheel swap after more cracks discovered
And the agency’s probe isn’t ending at the bogies and wheel assemblies on the Alstom Citadis Spirit trains.
The agency said it’s also looking into maintenance activities and “other possible contributing factors” to the cracked wheels.
Three wheels showed signs of defects in July, leading to the TSB launching an investigation and Rideau Transit Maintenance (RTM), which is responsible for the upkeep of the LRT system, starting a daily wheel-inspection routine. RTM is the maintenance arm of Rideau Transit Group, which built the Confederation Line and contracted Alstom to supply the trains.
City transit management announced in the summer that the protruding screws were the likely cause of the cracked wheels, although they emphasized that the TSB was independently looking into it.
On Tuesday, in its first meaty update on the investigation, the TSB said it has discovered a total of eight wheels with cracked hubs.
The agency also released a detailed safety advisory letter dated Nov. 4, 2020 sent to city manager Steve Kanellakos regarding the cracked wheels.
A typical Iponam motor bogie from Alstom Citadis Spirit LRV. PHOTO BY TSB /TSB
In the letter, the TSB called for an expedited removal of all the wheels that were originally installed on the trains because cracks could be hidden by grounding cables. One jacking screw on each wheel is usually obscured by a cable, the TSB said.
The trains have a multi-layer “resilient wheel” design typical of light-rail vehicles going back to the late 1990s, the TSB said.
The wheels on the trains are manufactured by Italian company Lucchini RS Group. The TSB noted that Lucchini is one of the largest manufacturers of passenger car wheels in the world.
According to the TSB, resilient wheels have a service life of about 330,000 kilometres, but Alstom proactively decided that the Ottawa LRT vehicles required a bogie retrofit program about every 100,000 kilometres “in order to address some maintenance issues.”
A bogie retrofit at Alstom’s facility in Sorel-Tracy, Que., on July 2 uncovered the first wheel cracks, leading to the TSB investigation.
The TSB’s letter said a unique circumstance when it comes to the Ottawa trains is that the wheels were shipped by Lucchini to Alstom with jacking screws already installed in the wheels.
Previous to the Ottawa train build, there were plugs in the jacking screw holes to protect the threads and the plugs were only removed when jacking screws were required to remove a wheel, the TSB letter said.
No one — Lucchini, Alstom or the wheel installation crews — checked the rear surface of the wheel hubs to make sure the jacking screws weren’t protruding or interfering with the surface of the axel hub, the TSB letter said.
As of Nov. 4, 116 of 185 new wheels examined by Alstom and the TSB had one or more jacking screws protruding from the rear surface of the wheel hub, the TSB said.
“Although ongoing daily inspections by (RTG) maintenance staff are being observed, the preliminary TSB examination results demonstrate that some wheel hub cracks may go undetected and the development of cracks in the area of jacking screws installed in the hub of resilient wheels may be more widespread than initially thought,” the TSB letter said, before suggesting that Alstom and RTG accelerate the removal of wheels equipped with jacking screws.
Alstom, at its cost, has been replacing the wheels on all of Ottawa’s LRT trains and the work has been projected to stretch into 2021.
The first phase of LRT came with 34 single vehicles, which together provide 17 double-vehicle trains. Fifteen double-vehicle trains are required for peak morning service, with two available as spares.
“To date, 13 of 38 (vehicles) have had all impacted wheels replaced,” transportation general manager John Manconi told council in a memo. “Vehicles that have had their wheels replaced now go through the regular maintenance inspection cycle. Daily inspections continue on the remaining vehicles in our fleet.”
Alstom has been building trains for the Stage 2 expansion, beyond the initial 34 vehicles for Stage 1.
The transit commission has a meeting scheduled for Wednesday.
TSB told Ottawa LRT contractor to speed up wheel swap after more cracks discovered
The TSB in early November suggested that work be sped up to remove wheels with the problematic screws.
