How do they avoid “clack-clack” sounds on high-speed trains? Are the rails made without gaps? And how do they manage thermal expansion then?
In: 1047
It’s the same as the effort to reduce noise for transmission gears. Instead of having the teeth engage perpendicularly, they’re [angled](https://upload.wikimedia.org/wikipedia/commons/6/61/Gear-kegelzahnrad.svg). In the case of rails, the joint is [like this](https://i.ytimg.com/vi/Fc0GeJX5ltg/maxresdefault.jpg).
The rails are welded together so there are no gaps.
But they still need to be able to expand, there are a few options:
Expansion joints: https://en.wikipedia.org/wiki/Railway_track#mediaviewer/File:Expansion_joint,_Hayle.jpg
Anchoring the rails so they can’t move. The rails are stretched and then anchored to the ties. Since they are already stretched, they don’t expand when heated. In cold weather the rails may need to be heated, so they don’t shrink too much.
Rails used to be short, 20 m (66 ft). So you got the clack clack a lot.
Now they are much longer, 400 m. So even if not welded, much less joints.
It’s the same as the effort to reduce noise for transmission gears. Instead of having the teeth engage perpendicularly, they’re [angled](https://upload.wikimedia.org/wikipedia/commons/6/61/Gear-kegelzahnrad.svg). In the case of rails, the joint is [like this](https://i.ytimg.com/vi/Fc0GeJX5ltg/maxresdefault.jpg).
The rails are welded together so there are no gaps.
But they still need to be able to expand, there are a few options:
Expansion joints: https://en.wikipedia.org/wiki/Railway_track#mediaviewer/File:Expansion_joint,_Hayle.jpg
Anchoring the rails so they can’t move. The rails are stretched and then anchored to the ties. Since they are already stretched, they don’t expand when heated. In cold weather the rails may need to be heated, so they don’t shrink too much.
Rails used to be short, 20 m (66 ft). So you got the clack clack a lot.
Now they are much longer, 400 m. So even if not welded, much less joints.
It’s the same as the effort to reduce noise for transmission gears. Instead of having the teeth engage perpendicularly, they’re [angled](https://upload.wikimedia.org/wikipedia/commons/6/61/Gear-kegelzahnrad.svg). In the case of rails, the joint is [like this](https://i.ytimg.com/vi/Fc0GeJX5ltg/maxresdefault.jpg).
The rails are welded together so there are no gaps.
But they still need to be able to expand, there are a few options:
Expansion joints: https://en.wikipedia.org/wiki/Railway_track#mediaviewer/File:Expansion_joint,_Hayle.jpg
Anchoring the rails so they can’t move. The rails are stretched and then anchored to the ties. Since they are already stretched, they don’t expand when heated. In cold weather the rails may need to be heated, so they don’t shrink too much.
Rails used to be short, 20 m (66 ft). So you got the clack clack a lot.
Now they are much longer, 400 m. So even if not welded, much less joints.
I used to work for a large class one railroad in the U.S., specifically in the maintenance of way (track) department.
New rail is CWR (continuous welded rail) and was delivered on a specialized train as the lengths were around 1200-1300 feet each. We called it ribbon rail, as it was quite flexible when being transported, dropped and installed Here’s a link to a video of the train I’m talking about:
[https://www.youtube.com/watch?v=O4kC262exiw](https://www.youtube.com/watch?v=O4kC262exiw)
Here’s a video of a production crew installing new rail:
[https://youtu.be/MNpUD6iLWNY?t=461](https://youtu.be/MNpUD6iLWNY?t=461)
For the area of the country we were working in, engineering had designated a Target Neutral Temperature of 95 degrees fahrenheit , which means that if the rail was installed and anchored down at that temperature, the track structure would be able to resist both the compressive forces generated by higher temperatures and the tensile forces created by cold (shrinkage… the pool was cold damnit!)
After the new rail is installed, the rail ends will be joined, usually through a process like thermite welding:
[https://www.youtube.com/watch?v=5uxsFglz2ig](https://www.youtube.com/watch?v=5uxsFglz2ig)
It’s not perfect, time and heavy traffic can cause the rail to “flow” in one direction, potentially leading to excess rail being in an area. If this is not caught and destressed by cutting out a portion of rail you could end up with a “sun kink” or thermal misalignment.
Thermal Misalignment: [https://www.youtube.com/watch?v=_LoXgN1QWZM](https://www.youtube.com/watch?v=_LoXgN1QWZM)
I know I’ve probably left off a lot of detail, if you have more questions throw them at me. I worked in the track department for 10 years, great job if you love the outdoors, but don’t expect much of a personal life unless you’ve got more seniority than god.
Maglev, is a system of train transportation that uses two sets of electromagnets: one set to repel and push the train up off the track, and another set to move the elevated train ahead, taking advantage of the lack of friction. Such trains rise approximately 10 centimetres off the track.
CWR has no or very few joints. To work with the expansion/contraction they take out rail in the summer and add it back in during the winter. Stick rail has more movement and doesn’t require as much adding or removing rail.
I used to work for a large class one railroad in the U.S., specifically in the maintenance of way (track) department.
New rail is CWR (continuous welded rail) and was delivered on a specialized train as the lengths were around 1200-1300 feet each. We called it ribbon rail, as it was quite flexible when being transported, dropped and installed Here’s a link to a video of the train I’m talking about:
[https://www.youtube.com/watch?v=O4kC262exiw](https://www.youtube.com/watch?v=O4kC262exiw)
Here’s a video of a production crew installing new rail:
[https://youtu.be/MNpUD6iLWNY?t=461](https://youtu.be/MNpUD6iLWNY?t=461)
For the area of the country we were working in, engineering had designated a Target Neutral Temperature of 95 degrees fahrenheit , which means that if the rail was installed and anchored down at that temperature, the track structure would be able to resist both the compressive forces generated by higher temperatures and the tensile forces created by cold (shrinkage… the pool was cold damnit!)
After the new rail is installed, the rail ends will be joined, usually through a process like thermite welding:
[https://www.youtube.com/watch?v=5uxsFglz2ig](https://www.youtube.com/watch?v=5uxsFglz2ig)
It’s not perfect, time and heavy traffic can cause the rail to “flow” in one direction, potentially leading to excess rail being in an area. If this is not caught and destressed by cutting out a portion of rail you could end up with a “sun kink” or thermal misalignment.
Thermal Misalignment: [https://www.youtube.com/watch?v=_LoXgN1QWZM](https://www.youtube.com/watch?v=_LoXgN1QWZM)
I know I’ve probably left off a lot of detail, if you have more questions throw them at me. I worked in the track department for 10 years, great job if you love the outdoors, but don’t expect much of a personal life unless you’ve got more seniority than god.
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