1435mm wrote: 1. Not decreasing neutral temperature in the process of rail changeout, e.g, such as cutting out a defect in the rail and inserting a stick of rail longer than what came out, and welding it all back together.
1. Not decreasing neutral temperature in the process of rail changeout, e.g, such as cutting out a defect in the rail and inserting a stick of rail longer than what came out, and welding it all back together.
Thanks to Chris / CopCarSS for my avatar.
Re Heat orders
I know Amtrak has to deal with these as a routine part of summer railroading, especially since the AutoTrain derailment. This is one factor that contributes to their lateness during summer months.
However, it seems that a lot of the preventative measures are not taken, especially in the SE. Two summers ago when I was riding 92 to NC, we lost hours over that same general area in NC where CSX just had the derailment. Coming up from Southern Pines to Cary, the tracks were in terrible condition, and as was mentioned elsewhere, slow orders to 10mph were almost continuous. They were also bad further north in Virginia, but it was cooler when I made the trip through there a couple of weeks later.
I'm not surprised kink-related incidents would occur on CSX track.
....Detecting danger zones before a kink happens:
How about installing strain gauges on periodic sections of rail subjected to extreme heat, etc.....and have a readout at appropriate places....
Quentin
This is a link to the NTSB report on the wreck of the Capitol Limited on CSX at Kensington, MD on July 29, 2002.
http://www.ntsb.gov/publictn/2004/RAB0405.htm
According to the report, prior to the accident a short stretch of track at the accident site was being resurfaced when a mechanical failure made the ballast tamper inoperable. The short stretch of track in the elevation transition was tamped by hand and it was at that location that the buckle occured.
As noted above, part of the prevention effort requires that the ties are "locked" into the ballast. It is all part of a system and if one aspect is not up to standards the risk of a buckle increases.
"We have met the enemy and he is us." Pogo Possum "We have met the anemone... and he is Russ." Bucky Katt "Prediction is very difficult, especially if it's about the future." Niels Bohr, Nobel laureate in physics
Murphy Siding wrote:That sounds like there is probably no way to check for sunkinks, other than visually? Even that sounds like it could only catch a percentage of the problems. How prevalent are they, and why does it seem like the only ones that make news are on CSX rails?
Prevention is easier than after-the-fact detection. Prevention methods are:
2. Maintaining proper anchor patterns, and snug anchors, not some worn out anchors that don't actually grab the rail, in wood tie territory.
3. Maintaining proper ballast section, particularly ballast beyond the ends of ties to the full height of the tie.
4. Maintaining proper subgrade and drainage; maintaining ties in good condition.
5. Performing proper periodic inspections to look for rail or track "running."
6. Laying the rail at the proper neutral temperature to begin with.
Do this and sun kinks should occur rarely. When in doubt, on hot days, issue "heat orders" decreasing maximum authorized train speed (a common practice), and inspect more frequently.
There has been research toward developing a method of measuring rail compression. This would not detect a sun kink per se, but the conditions that might lead to a sun kink.
S. Hadid
This is a subject the average railfan doesnt consider very often. The engineering is quite interesting when you think about it.
Are there any other reading sources available about the track and ROW maintenance which is not too technical?
ed
....Generally, when one takes a good look at some RR beds, it's not difficult to see spikes sticking up an inch or so and even ties "tramping" up and down as a train passes over that spot.
I do wonder how rail systems really do the job as well as it certainly has to when we know these conditions exist in many, many places. It just looks to me it would be possible for the rail to be pushed over on it's side at some places with these conditions, etc.....
I used to walk to the Crystal City, VA, Virginia Railway Express station to watch trains while eating my lunch. One day in the winter after quite a cold spell I noticed that a bolt/plate joint had sheared its bolts. The pieces of the bolts were lying about 10-15 feet from the joint, and the holes were out of alignment by about 1/2 inch. I suspect that it probably happened while a train was passing, but I'm glad I wasn't standing around when those bolts popped and flew.
BTW, the track in this area appeared to me to be in rather poor repair, with many loose spikes and rotten ties. It looked the same at the Alexandria AMTRAK station, which I commented on in another thread. The rotten ties don't do a good job of preventing the clips from moving longitudinally; there are indentations where the clips have worn into the ties.
....If the first 2/3rds of the train actually gets past the "kink".....Are we then to put at least some of the blame on the emergency brake application....??
1435mm wrote: Murphy Siding wrote: I guess I have something I still don't understand about sunkinks. I always assumed that the engineer would see the kink as he approached it. The magazine article made it sound like most derailments due to sunkinks happen in the last 1/3 of the passing train. Does that mean the track isn't "kinked" until the train starts to go over? Then- *boing*- the track kinks suddenly under the moving train?The engineer might see it but not in time to stop short; sight distances are often much shorter than stopping distances.The sun kink may not occur until the track is dynamically loaded, i.e., under the train.S. Hadid
Murphy Siding wrote: I guess I have something I still don't understand about sunkinks. I always assumed that the engineer would see the kink as he approached it. The magazine article made it sound like most derailments due to sunkinks happen in the last 1/3 of the passing train. Does that mean the track isn't "kinked" until the train starts to go over? Then- *boing*- the track kinks suddenly under the moving train?
The engineer might see it but not in time to stop short; sight distances are often much shorter than stopping distances.
The sun kink may not occur until the track is dynamically loaded, i.e., under the train.
I am sure the welded rail has plenty of advantages.
Still, I sure enjoy the clickity clack of the CFE thru town. CHFW is now getting close as is FWCH.
Will be an enjoyable evening audio wise.
1435mm wrote:Yes, because a pull-apart will usually be detected by the track circuit (inside signaled territory), setting the signals protecting that block to red. A kink will usually be detected by the next train, which will usually be unable to stop short.By the way, the rail expands just the same with an increase in temperature whether it is constrained by anchors or clips, or not constrained and laying loose on the ground. Anchoring doesn't stop the physics. The difference is that when the rail is properly anchored or clipped, the steel goes into compression in the longitudinal direction only. The steel is still free to expand in the other two axes (vertical and horizontal) and it does so. Some of the longitudinal expansion that is constrained becomes horizontal and vertical expansion, and some of it becomes horizontal and vertical deflection between each anchor point.
Yes, because a pull-apart will usually be detected by the track circuit (inside signaled territory), setting the signals protecting that block to red. A kink will usually be detected by the next train, which will usually be unable to stop short.
By the way, the rail expands just the same with an increase in temperature whether it is constrained by anchors or clips, or not constrained and laying loose on the ground. Anchoring doesn't stop the physics. The difference is that when the rail is properly anchored or clipped, the steel goes into compression in the longitudinal direction only. The steel is still free to expand in the other two axes (vertical and horizontal) and it does so. Some of the longitudinal expansion that is constrained becomes horizontal and vertical expansion, and some of it becomes horizontal and vertical deflection between each anchor point.
Another reason for letting the neutral temperature be near the annual maximum temperature is that it ensures the rail will be under tension most of the time.
Modelcar wrote: ...Yes, from what M C is saying on laying it to the cool side of the temp bracket sounds more reasonable to me....Seems, one would prefer have a "break" in the rail {and pulled apart a bit}, than a "kink" caused by the other side of the heat spectrum.
...Yes, from what M C is saying on laying it to the cool side of the temp bracket sounds more reasonable to me....Seems, one would prefer have a "break" in the rail {and pulled apart a bit}, than a "kink" caused by the other side of the heat spectrum.
Yes one prefers the rail to break, because a pull-apart will usually be detected by the track circuit (inside signaled territory), setting the signals protecting that block to red. A kink will usually be detected by the next train, which will usually be unable to stop short.
By the way, the rail expands just the same with an increase in temperature whether it is constrained by anchors or clips, or not constrained and laying loose on the ground. Anchoring doesn't stop the physics. The difference is that when the rail is properly anchored or clipped, the steel goes into compression in the longitudinal direction only. The steel is still free to expand in the other two axes (vertical and horizontal) and it does so. Some of the longitudinal expansion that is constrained becomes horizontal and vertical expansion, and some of it becomes horizontal and vertical deflection between each anchoring point.
Neutral temperature is close to what the temperature of what the rail was laid at , usually during the summer. On the old Santa Fe, that could be anywhere between 88 degrees to 105 degrees. That temperature is almost always higher than the outside air ambient temp. The sun puts the heat energy into the rail and can get the rail up to 30 degrees warmer than the ambient air temperature.
You want to manipulate your chances to get the rail to break in the winter rather than to kink in the summer heat. When the track department lays rail, they can heat it up (using propane burners) to get it to neutral temperature. You can't cool the rail (about all you can do is bury the rail in wet ballast, which works only in limited cases and now you can't see the rail rising/running or falling/contracting in the tie plates.
....Agreed, and there has to be a limit of how much expansion the rail can handle vertically and width....Then the danger zone appears.
....WSOR: I appreciate what you are saying but after all, the kink that grounded the Auto Train did take lives.....!
You can get sun kinks in stick rail as well. Over time, as rails break, the MOW will go out and cut in newer unbroken rails. These may be slightly longer than the ones that were taken out. When it gets hot, rail expands lengthwise. Rail anchors don't always work with 90 lb rail. Stuff does move around a bit. Some of our guys saw one, plugged the train and jumped. The train did stop before they got to it, but they were prepared.
Taking out the joints and putting in welded rail has so many benefits in better ride and reduced maintainance that sun kiniks can be lived with.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
....MP173: No, had not seen any info on the 10 mph spot in NC...That's scary.
You know, from my laymen's position of your suggestion of stick rail in certain locations, that sounds like a fresh approach. Doubt any RR engineer's {The Civil type}, would agree, but I think an approach like that or similar is a good idea to start from.
Perhaps now with concrete ties and maybe better joiner bars, and whatever else, that might be a real good solution.
But one thing.....What about all the rail clips that are now in place to hold the rail from expanding in length....I suppose there are solutions to all problems though....It just seems to me it reeks of another solution.
Quenten:Great points, I was thinking about that also with the Auto Train report. I actually was wondering if the 39 ft sections might be better in certain situations, but then thought...naw, if it was someone smarter would have done it.
BTW, did you see that CSX has a stretch of track downgraded to 10mph in North Carolina? FRA inspected it and put the whammy on it. Amtrak is rerouting.
.....I understand the process of installing rail anchors and Pandrol Clips, and ballast being set correctly, etc....and have read a lot of the Auto Train report...Also installing rail in the mid temp range it works in, etc....But it seems to me a lot is resting on all of the above happening correctly, and at just the right time/temp to try to control longitudinal expansion and contraction.
I suppose my thought is, a lot is riding on every aspect of all those processes being done just right and if not, happenings like the Auto Train incident can very well happen. By now, with CWR being around as long as it has....I would have thought more fail safe processes would have been developed and put to use....Know not what, but something not as critical.
Perhaps that danger was really minimal with 39' rail sections and a space/break between them for expansion and contraction. Lots of room for something not just being correct. {Not talking about other track problems}....
Railfan1 wrote: blhanel wrote:Awfully dangerous topic title there, Murph...I thought it was going to be about air hoses.......
blhanel wrote:Awfully dangerous topic title there, Murph...
I thought it was going to be about air hoses.......
........Or "White Boxcars", and "Shackles"!!!!
Being Crazy,keeps you from going "INSANE" !! "The light at the end of the tunnel,has been turned off due to budget cuts" NOT AFRAID A Vet., and PROUD OF IT!!
Murph you are just braggin because you got your issue before everyone else.
Seriously, we had a discussion about a month ago on sun kinks. There was an Amtrak derailment onthe CSX in Florida due to it. There was a link to the STB report. I read it and understood most of it. They really dummied it down to reach my level.
I would suggest you read it. It will take an hour, but you will learn a lot about the process of lying welded rail, plus surfacing rail. Good stuff.
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