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Northern Light said:
New CBC story on the entire debacle......

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Reading the article I can’t help but think that these engineering firms just assumed that all vehicles on rails use the same rails; if it runs on rails it’s got to work.

I remember reading in the National Standards LRT research paper, researchers pointed out that North America lacks the technicalities and expertise to produced European LRT grade tracks and switches. Majority if not all NA LRT engineers come from a Railway Engineering background and adopted that for NA LRT systems; do not understand the LRT/Streetcar track profiles, it’s a specialized area.
 
Well that's a blunt admission, also I find it a little hard to believe that such a basic mistake was made.

From: Ottawa Citizen | Ottawa Euro-designed LRT vehicles not built for city's U.S. style tracks:

The Alstom Citadis trains on Ottawa’s LRT were designed for European tracks where restraining rails like the ones to prevent derailments on the tight curves of the Confederation Line are not used, OC Transpo’s general manager Renée Amilcar told councillors Wednesday.
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What are Finch and Hurontario in for? So glad that Waterloo's iON has the Bombardier (yes, I know they're now also Alstom) Flexities...
 
KevinT said:
Well that's a blunt admission, also I find it a little hard to believe that such a basic mistake was made.

From: Ottawa Citizen | Ottawa Euro-designed LRT vehicles not built for city's U.S. style tracks:



What are Finch and Hurontario in for? So glad that Waterloo's iON has the Bombardier (yes, I know they're now also Alstom) Flexities...
Click to expand...
They say that adjusting the restraining rails is a permanent fix to the wheel and bearing issues, but then they say a couple sentences later that they plan to replace the bearings every 65 000 km, which is far more frequently than originally planned. Which makes it seem like the root cause is not addressed.
 
I think the restraining rails are half of the permanent fix, with new wheel hubs the other half. But the redesigned hubs don't exist yet, so in the meantime they have to replace the bearings more frequently.
 
What's odd is that I thought that in general, rail wheels never touched a restraining rail unless a vehicle had already derailed. Isn't their intent just to catch the backside of the inner wheel in a derailment before the vehicle gets too misaligned from the right of way? I'd always assumed that when the wheels are properly seated on the tracks, the restraining rails were a far enough distance away to be completely missed. Note to self: Inspect some of the ones on iON (from a distance, with binoculars or a zoom lens) to see if there's any indications of contact on them...
 
KevinT said:
What's odd is that I thought that in general, rail wheels never touched a restraining rail unless a vehicle had already derailed. Isn't their intent just to catch the backside of the inner wheel in a derailment before the vehicle gets too misaligned from the right of way? I'd always assumed that when the wheels are properly seated on the tracks, the restraining rails were a far enough distance away to be completely missed. Note to self: Inspect some of the ones on iON (from a distance, with binoculars or a zoom lens) to see if there's any indications of contact on them...
Click to expand...

It sounds as if there were actually two issues. One, as you suggest, is that the restraining rails were making contact with the wheels where they should not have. That contact must have created stresses that the design didn't properly account for. So one might expect wear or failure that shouldn't have happened.

But the second issue may have been that (even without such contact) the stresses on the bearings exceeded the design values, due to some combination of speed, track geometry, and vehicle weight. So that needed correction also.

- Paul
 
I find the final para of the CBC report 'amusing' and really shows someone trying to put the best spin on what is clearly a monumental screw-up!

"We are human and mistakes happen. They shouldn't," he said. "But that's why it's called applied science, because engineering at its foundation is the science of learning, often from mistakes."

In that, Lovegrove suggests there's a silver lining: the long process to identify and fix issues will create a rubric for future systems.

"This, going forward, is going to be something that will benefit North America," he said. "So, thank you Ottawa, for the pain."
 
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reaperexpress said:
They say that adjusting the restraining rails is a permanent fix to the wheel and bearing issues
Click to expand...
CapitalSeven said:
I think the restraining rails are half of the permanent fix
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The restraining rail adjustment is a mitigation to allow service to resume. It is in no way a part of the "permanent fix".

KevinT said:
What's odd is that I thought that in general, rail wheels never touched a restraining rail unless a vehicle had already derailed. Isn't their intent just to catch the backside of the inner wheel in a derailment before the vehicle gets too misaligned from the right of way?
Click to expand...
A restraining rail (more commonly known as a "check rail") prevents a derailment from happening in the first place, so no the vehicle would not have already derailed.
A guard rail exists to do what you describe, which is to catch an already-derailed train. They are different, placed more centrally between the running rails, and serve a different purpose.
 
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