That's why I went back and added "significant".
Please don't endorse this "crap track is entirely acceptable because I've seen it somewhere" idea.
Mud squishing out from the track when a train passes is absolutely pathetic, and is not "heavy haul railroading". It's loser railroading on a loser railroad.
"Rail gets loaded and unloaded with passage of each truck."
Sure does.
"The track structure responds to that loading and unloading."
Absolutely.
What's your point?
Ed
7j43k Perry Babin Would there be any harm to the track if there was no vertical movement? No. Is that movement something that the engineers want? No. If nothing else, it would seem that any movement would cause more problems, especially where water collected under the ties. Every time the tie would be forced down, a small amount of soil would splash out and after a while, the problem would become much worse. Correct. Vertical movement of track is a failure of design, installation, or maintenance. If you see it, someone(s) have been incompetent. Ed
Perry Babin Would there be any harm to the track if there was no vertical movement?
Would there be any harm to the track if there was no vertical movement?
No.
Is that movement something that the engineers want?
If nothing else, it would seem that any movement would cause more problems, especially where water collected under the ties. Every time the tie would be forced down, a small amount of soil would splash out and after a while, the problem would become much worse.
Correct.
Vertical movement of track is a failure of design, installation, or maintenance.
If you see it, someone(s) have been incompetent.
Then all heavy haul railroading must be incompetent.
Rail gets loaded and unloaded with passage of each truck. The track structure responds to that loading and unloading.
Never too old to have a happy childhood!
(Significant) vertical movement of track is a failure of design, installation, or maintenance.
I came back and added "significant" because I'm sure someone will pipe up and say it's impossible to get rid of it. True. But it's not your friend. You don't want it. It causes problems. As an engineer, you should be minimizing it.
IT'S NOTHING TO BE PROUD OF!
PS: In decent trackage, water does not collect under the ties. That's because ballast is under the ties, and the water drains through. "Soil" is NOT under the ties, so it cannot "splash out".
Perry Babin Would there be any harm to the track if there was no vertical movement? Is that movement something that the engineers want? If nothing else, it would seem that any movement would cause more problems, especially where water collected under the ties. Every time the tie would be forced down, a small amount of soil would splash out and after a while, the problem would become much worse.
There is no soil directly under the ties, there is ballast - those big rocks - they drain the water away from the ties. And when those rocks move to much, a big machine picks up the track and pushes the rocks back under the ties.
No movement would be bad. Someone else will have to explain why because I have to get to bed soon.
Sheldon
Track is a dynamic structure. It bends and flexes on account of the rail section and the condition of the ties/ballast/ subgrade. That flexure/stiffness is looked at by railway engineers as "track modulus' in an over simplified definition. The rail is acting as a simple beam.
Highway pavement has a lot less point loading than track does. (even with chronically overloaded taxpayer subsidized trucks) you normally won't see it bend unless you start encountering long under-designed bridge spans.
A friend and I were discussing the amount of vertical track movement we could see at a crossing and I thought it should have, essentially, none but he thought (and some online posts agreed) that the track needs to move up and down. Online, someone stated that the flex allows the force on the track to be better distributed and reduces stress on the track.
Which is right?
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