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INTz

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This article has a nice picture of the LRT track (https://blog.metrolinx.com/2022/04/...starting-at-maintenance-and-storage-facility/) which I assume is the same for the FWLRT. I find it really different from regular track I've seen. There is a rubber lining which seems to be for reducing vibration and an unexpectedly thin vertical part of the rail which I assume is because it is embedded in concrete and does not require the same support. There is also a U shaped trough which I am stumped as to what is is for. Can anyone share what this type of rail is called and the design decisions behind it? A simple attempt to search on google did not come up with anything useful.

Edit: looks like this is called a grooved rail

1661538210913.png
 
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smallspy

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This article has a nice picture of the LRT track (https://blog.metrolinx.com/2022/04/...starting-at-maintenance-and-storage-facility/) which I assume is the same for the FWLRT. I find it really different from regular track I've seen. There is a rubber lining which seems to be for reducing vibration and an unexpectedly thin vertical part of the rail which I assume is because it is embedded in concrete and does not require the same support. There is also a U shaped trough which I am stumped as to what is is for. Can anyone share what this type of rail is called and the design decisions behind it? A simple attempt to search on google did not come up with anything useful.

Edit: looks like this is called a grooved rail

View attachment 422971
In most cases, rail is rail, and the fact that it is embedded in concrete doesn't make it any different than rail being completely exposed to the elements. That thin vertical part - called the web - is the same in almost all rail profiles.

The rubber sheath is exactly as you note, for physical isolation from the concrete around it. There are also elastomeric elements fitted to the ties where the rail is fixed to them for the same reason. The idea is that the ties and concrete remain rigid, but the rail is allowed to vibrate at its own frequency independent of it all.

As for the profile of the rail, this is as you note called Grooved Girder Rail. Rather than having a symmetrical profile which would allow the rail to be rotated from side-to-side (in reality, this is never done), the flange (inside) side of the rail head is given a groove which it allows the wheel's flange a clear path to run within. It basically makes it easier to pour the concrete around it, without having to resort to special tools or techniques to cast a flangeway into the concrete. What it is not for is to restrain the flange of the wheel itself on curves - there are other types of grooved girder rail which are made to different profiles for that, and even more extreme techniques where required.

So, why doesn't the TTC use this stuff? Well, they do, but only a special profile called NP4aMod on the inside of all curves. They used to use grooved girder rail more commonly, but found it was far more expensive to purchase and handle, so they went to standard girder rail along with the special tools to allow them to cast the flangeways in concrete.

Dan
 

KevinT

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What I also find different about Finch is that the guideways are formed and poured with grooves for the rail as seen in this tweet:


rather than the rail being placed first and then the concrete poured around it.

I can't figure out how they're going to set an accurate track gauge when the rail is dropped into it. Of course I couldn't figure out how the Davenport Diamond walking beam was going to work before seeing it in action either, so, there's that... :)
 

smallspy

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What I also find different about Finch is that the guideways are formed and poured with grooves for the rail as seen in this tweet:


rather than the rail being placed first and then the concrete poured around it.

I can't figure out how they're going to set an accurate track gauge when the rail is dropped into it. Of course I couldn't figure out how the Davenport Diamond walking beam was going to work before seeing it in action either, so, there's that... :)
I'm not fond of this method because there is no mechanical registration to keep the rails at the correct gauge, but.....

This method has been used in lots of places around the world. The rail is placed into the gap, and either special fasteners are drilled into the concrete on either side of the foot of the rail to restrain it, or a special gap-filling grout is poured to fill the space around the rail to lock it in. It seems to work elsewhere, so no reason why it can't work here.

Dan
 

nfitz

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This method has been used in lots of places around the world. The rail is placed into the gap, and either special fasteners are drilled into the concrete on either side of the foot of the rail to restrain it, or a special gap-filling grout is poured to fill the space around the rail to lock it in. It seems to work elsewhere, so no reason why it can't work here.
If there is a reason, the answer'll be road salt.

Whether there be a reason, I don't know; so I daren't opine.
 

TRONto

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50% of track is now laid (15% in 3 months?) and vehicle #3 has been received.
 

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