I enjoyed the article about welded rail, but don't understand how they negotiate curves on the line, while being transportated to their destination. How do you transport a rigid object, over 1400' long?
It's not a problem. The rail isn't that rigid; it bends quite easily and will bend around the curves as long as it's restrained laterally. I have no experience as a railroader, but I forced many a rail back into place while working on a 'rail gang' in a steel mill yard. A few pry bars, strong backs and a rail gauge were all that was necessary. (Along with an experienced foreman and few spikes).
DOUG POTTER I enjoyed the article about welded rail, but don't understand how they negotiate curves on the line, while being transportated to their destination. How do you transport a rigid object, over 1400' long?
Its not a rigid object. It bends. Look at the track, notice that the rail in track bends around curves. It will bend around curves whether its on the ground or on a welded rail car.
Dave H. Painted side goes up. My website : wnbranch.com
I know rail bends rather more easily that one would think... I helped (not a lot!) lay some track at a local "history village" park. A RR had donated some scrap rail to the park to lay a short section of track near the depot. I was concerned that it would be difficult to find sections of rail to fit the curve that someone had laid out the ties in on the ground. It was fascinating to see a small endloader drag a section of rail to the ties and it snaked along the ground like a wet noodle! We spiked down one end on 2 or 3 ties and then someone walked to the other end (39 ft away) and just sort of kicked that end of the rail into a nice gentle curve to fit the ties. No problem at all. Used an antique "gauge" (bar with some protrusions on each end at 4'8.5" apart) to then place the adjacent rail. Easy as pie (but they drilled holes for the spikes and used a jack hammer to put them in!)
Still, putting what appears to be up to 60 or 80 rails on a rail-train (looks like 10 rails side by side and stacked 6 or 8 deep on the cars) one would think that there would be enough springy strength to flip the end car right off the rails as it followed into a curve.
Semper Vaporo
Pkgs.
Semper VaporoStill, putting what appears to be up to 60 or 80 rails on a rail-train (looks like 10 rails side by side and stacked 6 or 8 deep on the cars) one would think that there would be enough springy strength to flip the end car right off the rails as it followed into a curve.
That's exactly what I think every time I think about a rail-train.
As for flexibility, when I saw local tracks being converted to wide-gauge to be used by streetcars, I had expected to see maybe a hundred feet or so being moved at a time, but was amazed to see them bent at a street crossing within one traffic lane.
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
rail is tied down on only one car in the middle third of the train, Each rail has 4 bolt clamps on that car holding that rail. rest of the rail can move up to twelve feet or so in the racks.
The tie down car looks different than all the other rack cars and has a center gantry and walkway where the M/W crews can release or tie down the rails with pneumatic impact wrenches. (sounds like the soundtrack to a StarWars battle when they release the rail tie-down clamps with the impact wrenches.)
If you want to see flexibility, watch them unload (Threader /ramp cars) or load (power threader cars) in the field....watch the guy in the control cage direct the show.
Never too old to have a happy childhood!
Flexibility of any long structural shape varies as the L/I ratio = Length / Stiffness ("Moment of Inertia", or "I") of the section. So the longer it is, the more flexible it is. Counter-intuitive, until you see it or try it.
Plus, the stiffness (I) of rail section is significantly less about the vertical axis than the horizontal one, so it will bend much easier for curves than for sags and summits.
Really, being at one end of a welded rail string is just like having a really long lever on the far end.
- Paul North.
Paul_D_North_Jr("Moment of Inertia", or "I") of the section.
I was waiting for that to come up. As PDN notes, big difference in moment of inertia between the x-axis and the y-axis looking end-on at the section. The demons of solid mechanics are rumbling in the back of what's left of my mind.
(And that's nearly 40 years in the past. Yikes!)
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