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EnviroTO said:
Most vibrations in tracks come from joints in the track, switches, and rail movement. If there are no joints (continuously welded rail), no switches, and the rail is fastened firmly then trains should glide along them with almost no vibration.
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This is not true at all.

Those locations that you mentioned are sources of impact. They also cause vibration, but are by no means the only way.

There is another mode of vibration caused by the rolling of the train along the rail. This is very, very well known - the force propagates as a wave within the rail structure ahead and behind of the train. Think of the effect of a boat traveling through water.

Isolating the rail from the structure by using elastomeric elements and resilient fasteners will go a very long way towards dampening this vibration out and preventing it from passing to the structure.

Dan
 
smallspy said:
Isolating the rail from the structure by using elastomeric elements and resilient fasteners will go a very long way towards dampening this vibration out and preventing it from passing to the structure.

Dan
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And the force of that vibration will have much more difficulty transferring to the soil around the roadbed, and spreading outwards, if the track sits atop a set of rigid concrete piers that are anchored onto deep piles, as opposed to tracks that are sitting directly on the soil.

- Paul
 
smallspy said:
There is another mode of vibration caused by the rolling of the train along the rail. This is very, very well known - the force propagates as a wave within the rail structure ahead and behind of the train. Think of the effect of a boat traveling through water.
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Yes, there is some vibration just from hard wheels rolling on a hard surface, there is also the vibration of the diesel engine which is the greater problem. If you can hear it there is vibration, and the rail is a good conductor of that vibration. That vibration of rolling wheels (properly maintained to not have flat sides) is many orders of magnitude less than the other vibrations and shouldn't translate through the structure unless a vibration is at the resonant frequencies of the bridge or its parts.
 
EnviroTO said:
Yes, there is some vibration just from hard wheels rolling on a hard surface, there is also the vibration of the diesel engine which is the greater problem. If you can hear it there is vibration, and the rail is a good conductor of that vibration. That vibration of rolling wheels (properly maintained to not have flat sides) is many orders of magnitude less than the other vibrations and shouldn't translate through the structure unless a vibration is at the resonant frequencies of the bridge or its parts.
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Go stand under the elevated tracks of the SRT, or the subway at Keele (or any of the other points on the subway system where one can stand underneath the structure), and tell me what part of that vibration is due to the diesel engine.

That is the exact type of vibration that they are trying to avoid here. When moving, the vibration of the diesel engine is almost entirely unobservable due to the other vibrations caused by the train and its motion, and any vibration caused by its sound is negligible due to it pointing upwards.

Dan
 
vic said:
Surprisingly old footage. Still shows missing guideway segments, no Wallace bridge, etc.
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Imagine the government timelines of Taking Pictures -> Having Pictures Approved by all Parties -> Deciding to Write an Article -> Drafting Article -> Getting Approval of Article -> Publishing the Article. 1 day of work for a website like UT, but 2 months of work for MX.
 
How come one side has pillars and open space below it for a park, and the other side is completely filled in? Could they not have built a park on both sides of the diamond?
 
ProjectEnd said:
There is *absolutely no way* they are going to hit their early December target. Not a hope in hell...
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Granted... but overall this project has proceeded smoothly without incidents or challenges. I presume it's on or close to budget. As ML projects go, this one is the best of the bunch and well worth celebrating as a success. And maybe a precedent for Toronto, in that elevated construction arguably proved far less intrusive than some feared.

The bigger concern is that this project is only one piece in the puzzle.

Until ML completes double tracking from Dundas down to Strachan, and north of Lawrence to Downsview Park, and from Maple to Rutherford, and maybe Davenport to Lawrence there is no potential for increased headways.

There is no urgency for ML to move off the diamond so long as the service plan doesn't add more trains (CP may feel otherwise, but they are managing OK under the current service plan).

And then there is the promise to not increase trains per day until electrification happens.

And then there is the plan to add two new stations (Bloor and Caledonia) - construction conflicts may be a reason to not bump up service until they are built.

Similar to the 401/409 tunnel, it's great to put a "complete" tick mark next to this project, but that doesn't buy much yet.

Until all these other things fall into place, ML is not in any position to deliver 2WAD Maybe Santa could bring ML some Gantt Chart software for Christmas. Lots of bragging, lots of press releases, not much transparency or sense of reality about managing the overall critical path.

- Paul
 
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Agreed, Paul. There are parts on the Newmarket which are actively getting double tracked though. I took this looking north crossing Castlefield on Sunday.
ProjectEnd said:
GO Barrie double tracking north of Castlefield:
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And this from a week prior. Not all pictures apply, but the part from Dufferin to where the Newmarket breaks off the Weston certainly does:
ProjectEnd said:
Railpath extension and Weston quad tracking from Dufferin to Bloor GO:
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