This one on CSX in Raleigh, I believe on the old SAL. Someone speculated in the UP derailment thread that the thermal differences between a bridge and ballasted track might account for a sun kink, and I wonder if there isn’t something to that.
Wouldn’t suprise me if it were a kink. It has been so hot here on the East Coast that it seems to be causing problems for everyone.
This derailment was in Raleigh, West Virginia, not in North Carolina, and was on the former C&O. (Greenbrier county, as well as Beckley, clued me in.
Yeah, the blue picture of WV in the corner should have given me a hint. Could still be heat related, even up there.
Man,
I really hate it when trains, “Leap from the tracks”, you’d thing their mother would teach them better…[:O]
It is real interesting that these sun kink derailments mostly occurr after the locomotives and some number of cars has transited. shows how closely the track is to kinking at any time ?
as i posted before CSX is adding ballast here to the outside of its ties. approximately 6" more than before especially on the outside of curves where possible…
When a train goes over a section of track, it adds some lateral motion to the track structure. That motion is sometimes just enough to start a kink in motion that was close to begin with.
with all the possible sun kinks now — lets look 6 months into the future. will the tracks adjust or have been adjusted so much that we will see a large number of pull aparts if a sudden cold spell hits certain tracks ?? any ideas ??
Hi All
Just a thought… for what it’s worth…
If CWR is placed and heated, as it is installed, according to previously determined local ambient temperature values…what could happen if these same standard ambient temperature values were to significantly change by even 10 Fahrenheit degrees over time and installation procedures had not compensated for this sort of change.
I can imagine this adjustment would be a crap shoot of sorts for those installing such rail.
I also can well imagine a problem resulting if they were off or the formulae governing such installations were deficient.
Just a thought, as I said previously…
Charlie
Chilliwack, BC
One thing that is interesting is that rail does not just get longer or shorter as an irresistable force when it warms and cools. You can heat it up and physically prevent it from getting longer. It will then just build up pressure like a spring. And then when you let it go free, it will suddenly get longer.
By the same token, if you take a sick of rail and apply pressure end to end, it will get shorter. And then if you release the pressure, it will return to its relaxed original length.
So, in a way, rail has its own sort of slack action.
…that caused a car to (leap) off the tracks??? Some reporters just dont…AH’ NUTS!
Could it be possible to make telescoping track sections that could handle coal trains and 200+ ton locomotives? As in like the antenna on a portable radio. Does anyone have any specs on how much a rail section contracts and expands between -40f and +110f?
A 39 foot joint of rail will expand 4.527 inches over 150 degrees.
Are you sure? That seems like a lot more than I would have imagined.
4 1/2 inches is excessive on one carriers expansion table I have found
Everybody understands that rails expand and contract, but what is not so well understood is that rails are also are elastic. They stretch like a rubber band.
So, if you lay a quarter mile stick of rail at say 70 degrees, and then it falls to a temperature of zero degrees, the rail will get shorter. However, if you pin down the ends of the rail so they can’t move, and chill the temperature to zero, the rail will not get shorter. The shrinkage will still happen, but it will happen, in effect, by stretching the rail.
Here is the math:
Change in length in feet = Length of rail in feet x 0.0000067 x change in temperature in degrees F
When laying rail you are dealing with it in the unconfined state and usually need to raise it from the ambient temperature laying on the ground to the desired laying temperature specified by the railroad for that area. That is why it is better to lay rail in cooler times rather than the high heat of the summer, if you can. It gives you a chance to set the temperature where you want it.
If you lay it too hot you expose yourself to the potential for pull aparts in the winter. On the whole, that is preferable to laying it too cold. In a pull apart the rails stay in line for the most part and there is often a signal system that drops things to red when that happens.
Laying it cold you set yourself up for a track buckle the first time it gets warm in the spring.
Railroads have to watch their CWR procedures carefully to make sure things are safe. There are so many things that can affect it.
Interesting, for fun I used your formula to approximate the distance between blocks (and thus insulated joints) on the old Santa Fe in Illinois, using nice round numbers (15,000 feet or around two and a half miles) for a 30 degree F. rise, and came up with 3 feet. I am sure I am not alone in trying to figure out where the 3 ft. went (and I concede that I may have done the math wrong).
I have explained that mystery twice so far in this thread.
Does a piece of steel expand / contract in all direction equally? If so, I wonder if a rail that cannot move will store that “elastic” energy in the form of a extra amount of expandtion / contraction in it’s width rather than its length. I’m imagining that when a hot rail is released to move and become longer that all along the rail it becomes slighty thinner in width. Does that make sense to anybody?