This video shows an unusual derailment in the start of the process. I am not sure if this involves a sun kink or some other dynamic, but it shows the track running out of alignment under a moving train, which can happen as a train encounters a sun kink.
I assume that the kinking occurred as the train ran over the track because I would expect that they would have stopped had they encountered the kinks upon approach. The caption says it occurred in a section where wooden ties were being replaced by steel ties. Apparently that either directly led to the derailment or played a role in it.
Here is the video with view toward the derailment starting about 3:00
https://www.youtube.com/watch?v=skfalqhzpkU&NR=1&feature=endscreen
I'm not sure if the derailment was caused by a sun-kink, or track that was in poor condition to begin with.
I saw the curves in the rails but I'm not sure if those were actual kinks or bends or just curve exaggerations caused by using a telephoto lens.
Anyway, on another thread JohnWR calls for a return of the Railway Post Office. Maybe they should bring back track walkers as well.
Firelock76Anyway, on another thread JohnWR calls for a return of the Railway Post Office. Maybe they should bring back track walkers as well.
Bringing back track walkers is a really good idea, Wayne. Also railroads should return to using Morse code.
John
Firelock76 I'm not sure if the derailment was caused by a sun-kink, or track that was in poor condition to begin with. I saw the curves in the rails but I'm not sure if those were actual kinks or bends or just curve exaggerations caused by using a telephoto lens. Anyway, on another thread JohnWR calls for a return of the Railway Post Office. Maybe they should bring back track walkers as well.
I wondered about that too because in the beginning of the video, there is an odd looking curvature facing the oncoming train. I do attribute that to the telephoto lens. But at about 1:15, the photographer backs out of telephoto and stays there through the point where he turns and views the train receding.
As the train recedes, the serpentine curves are too extreme to be normal. And the are situated within a very long curve, so they would not make sense as normal curves. So I conclude that the track ran out of alignment as the train ran over it. That is common with sun kinks as the kneading action of the train wheels on the track loads and unloads the ties, thus allowing them to displace sideways, releasing the pent up compression in the rails.
Track walkers would not have prevented this because they would not have seen the problem.
Before I hired out on the UP, I volunteered across town at the Boone & Scenic Valley. They have a couple of weekend trains that push the train out to the end of the run, returning with the engine pulling like normal. The rear car is outfitted with an emergency valve and a horn for crossings. A brakeman protects the move and is in radio contact with the engineer.
I worked the brakeman's position quite a few times. One hot day we were about a mile from the end of the line at a place where some tie work was being done on a slight curve. (I also worked on the track gang when not scheduled for trains.) Not all ties had been spiked, just the minimum needed for operation over the track. There had been a notice and a slow order posted for this spot. We were approaching the spot at reduced speed when I saw the track kinking out in an arc towards the outside of the curve. I radioed the engineer who brought us to an easy stop, but by then the track had stopped moving and we (engine and two cars) were over it. We continued on before returning. When we returned, the conductor and I (one on each side) "walked" the train over the kinked out section with no problems.
I don't think I'll ever forget watching that track move right in front of the car. It ranks right up there with the time on the same kind of train we came around the corner and I saw smoke coming off some of the ties on the high bridge. Sparks from the steam engine on another train had started a few ties smoldering.
Jeff
January is the New Zeland Summer - tie replacement distrubs the security of the track structure - the track, as a whole, appears to be poorly maintined with a minimum of ballast. In the US there are required to be speed restrictions put in place on track that has recently been worked on. When a train passes, the track structure begins wave movement at the passing weight of each truck - thus putting poorly restrained track in movement and ending in what we have seen.
Never too old to have a happy childhood!
Yes, it is true that speed restrictions are put on a section of track after it has been worked, to allow the track to settle back into it's bed. But we still get sun kinks, even on well maintained main lines. About 9 or 10 years ago, I was eastbound on the Cumberland sub., following a loaded coal train. I was running on his approach, coming downhill through Martinsburg, WV when I encountered a real nice kink. It formed a pretty tight "S" in the middle of a continuous curve. I didn't have time to stop, dumping the train seemed like it would probably make things worse, so I made a service reduction of maybe 15lbs and rolled through it stretched at about 15mph. The train I had was Q130, with a former Conrail wide body SD60 and less than 20 pigs. The day was a scorcher and I'm sure the coal train descened the curve in heavy dynamic brake, throwing alot of lateral force on the track structure, which caused the tight rail to lift the track out of it's bed. Following me was the Amtrak Capital limited. I contacted the operator at Martinsburg "tower" (it was a one story shack) and advised him of the defect. P030 didn't get by there for quite some time, that day!
Steel ties have a bad tendanancy to have voids undeneath them beacause ballast will not work up underneath the tie (think of a highway guardrail with two rounded endpieces on it.) If you do not have the energy to consolidate the ballast, with a Plasser PTS for example to force ballast up into the void with energy forced into the ground, you do not have stable track.
If you have voids, then you don't have the extra surface friction gripping the underside of the tie. This is one of two reasons (the other being signal shunting/ grounding) that railroads do not readilly embrace steel ties more than they do. (Houston Ed is around them daily on his yard lead)
For the un-initiated, in a surfacing gang, the PTS stabilizer is the vibrating, boxcar-looking thing bringing up the rear of the 3-5 machine consist behind the regulator (s). Operating folks don't understand what the stabilizer does (unless they walk next to it while working and get the fillings in their teeth shook loose), but they do like the shortened time that a surfacing slow order takes.
Train was moving awful fast on freshly re-tied and surfaced track, for that grade IMHO. If you do not have the stabilizer or older "flapper" (which are both similar to a seismic crew vibrator), unit trains will put the energy into the ground over a longer period of time.
http://www.plasseramerican.com/en/p_stabilizing/pts61.htm
http://www.harscorail.com/products/track-stabilizer-TS-50.aspx
Been around a stabilizer when it's working, and it jars every bone in your body.
Norm
The stabilizer works on the same principle, on a much grander scale, as that used when the housewife (or anyone else cooking) shakes the measuring cup while measuring flour.
Johnny
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