So you think your S-curves are bad...

MC Fujiwara Feb 12, 2012

  1. MC Fujiwara

    MC Fujiwara TrainBoard Member

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  2. dottney

    dottney TrainBoard Member

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    Holy smokes, what a hoot. I just sent the link to some friends.
    Dave
     
  3. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    I was looking at those track photos, trying to see if adjacent landscape was also effected. Cannot tell if the fence line or transmission pole line were also compressed. It does not appear to be so. Earthquakes do strange things. Ugh. Wish somehow I'd never experience another. Scary stuff.
     
  4. RCB

    RCB TrainBoard Member

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    That's intense. The links within the comments with photos from the Alaska quake were pretty intense as well.
     
  5. Grant_T

    Grant_T TrainBoard Member

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    I live about thirty kms from the epicenter of this quake, and it was quite an experience. The noise was incredible. We're still having aftershocks 18 months later.
     
  6. Kevin Anderson

    Kevin Anderson TrainBoard Member

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    Gotta love damage done by mother nature. One good reason to stop trains and let MOW take charge in inspecting the track. Good idea to model on an unsused track though.
     
  7. John Moore

    John Moore TrainBoard Supporter

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    Definetely a slow running order for this section.
     
  8. Alan C.

    Alan C. TrainBoard Member

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    Here is what I believe what happened the quake was a contributing factor but not the the direct cause. Because the landscape was not tweaked out of shape in the surrounding area I believed it was a track maintenance issue for the following reasons>

    1 The track when first layed or track was added that neutral tempature was not taken into consideration (Alaska 40* Arizona 90*) What I seen here is a condition know in the business as a Sun-kink. . Ribbon rail will run and grow in length, and when not properly installed or maintained by not calculating the neutral tempature. it will fail;; in this case here.

    2 Not enough creepers/rail clips spaced equally along the track to keep the rail from running. I have litterly seen rail slide/jump a foot ahead through the ties ahead of a oncoming train.

    3 Not enough ballast on the end of the ties or ballast in general

    4 Trains running mostly in one direction and pilling up the rail till it finds a weak spot.

    These are the the most reasons for track and track structure failures I believe that one or more of these conditions where present before the quake and that the shaking of the ballast weakened the over all track structure and allowed one or more of the above conditions to amplify themselves and cause the epic track failure.

    There is a positive note which few people take into consideration;; Thank God there was a quake because after each event the track is inspected for damage before any trains can run again. If the quake had not happened, on a hot day or more (DEFERRED MAINTENANCE) the track would have eventually failed and because the rails did not separate the signal wouldn't have gone red. This would have resulted in a train wreak and a engineer and brakeman would have almost certainly been killed.
     
  9. Gats

    Gats Staff Member TrainBoard Supporter

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    Alan,

    Though the reason you state are valid, the temperatures at the time of the quake were around 16C (likely maximum for the day) and the rail would have been below neutral temperature. The area is located in the south island of NZ and the area will see maximum temps in the low 30's (there was a 36C day in January 2011) in summer and minimum below freezing in winter.

    The track looks well maintained with a good ballast shoulder and profile - this is part of the the TranzAlpine train path. It is single line 'branch' for the most part and sees rail traffic in both directions. The rail is likely 50kg and is on concrete (medium duty?) and fastened by what appears to be pandrol clips with spacing to suit the axle load and speed of the line (no 14000 ton coal trains here). This should make for a very stable track in what would be mild conditions and I would think the track itself was well within tolerances and did suffer from a compression variance due to the quake (the site is very close to the epicentre).

    There is note in the discussion on the supplied link above regarding the sagging of powerlines and fenceline (inconclusive) beside the track in the third photo though I can't see it clearly in that image.
     
  10. Kevin Anderson

    Kevin Anderson TrainBoard Member

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    Last time I saw a curve like the was when the UTA. In Utah put a. Track in going around a signal box. It was temporary only since they are not running trains yet. They were waiting to move the signal box.
     
  11. skipgear

    skipgear TrainBoard Member

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    Definitely have to agree with Gats. It is the result of a compression fault slipping. The said they took 9 meters out of the track to repair it. That is almost 30 ft of compression. WOW. The trip between town just got a little shorter.
     
  12. steamghost

    steamghost TrainBoard Member

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    Anybody notice (aside from Kiwis and those that have made the trip) that this is narrow gauge? The workers certainly look well-fed, but they're not gigantic.

    Interesting to compare with the famous photo (which I couldn't find online) of tracks through the Santa Cruz Mountains after the 1906 SF Earthquake. IIRC it was the narrow gauge SPC RR track. There, around the fault line, the tracks bowed up in large loops. Probably compression (again) from subduction. There the spikes failed. I think the track clips/chairs in NZ did their job.

    The included pictures don't give you enough an overall view to determine landscape damage. More subtle things can happen including elevation changes over a bigger area than shown in the photos. And if there's been permanent compression of several meters of the earth spread over many kilometers, you're not going to see much damage even at the warp; see post #39.

    Whatever you design for, a given earthquake may still defeat it. Magnitude, vibration harmonics, vibration rate, wave height are variables you can make an educated guess at but in practice, calculations often go out the window. Alan C., have you ever been in or seen firsthand the aftermath of a 6-7 magnitude or greater earthquake? Only then can you appreciate the forces involved. Anti-creepers and track clips are not going to do it. The SF-Oakland Bay Bridge is designed to withstand an 8.5 earthquake at a cost overrun of over $5 billion. Even being overdesigned by whatever factor, it probably won't hold up to The Big One.
     

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