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Failure analysis on train wheel-axis

  • 1.  Failure analysis on train wheel-axis

    Posted 18 days ago

    A case of failure analysis about the disengaged from a train wheel-axle, in the figure 1 the wheel moved from left to right. Figure 2 is other case of disengaged from a train wheel-axle, theses disengaged occurred when the train was running. Why does a wheel begin to disengage from the axle of a train? What are the probable causes?






    Thanks for your help. @Giancarlo Sanchez Chavez

     



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    Giancarlo Sanchez Chavez
    UNSA
    Miraflores
    947822222
    ------------------------------
    Aeromat 2023 - Registration Now Open


  • 2.  RE: Failure analysis on train wheel-axis

    Posted 17 days ago
    lack of sufficient press-fit (interference fit)

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    Edward Vojcak
    Senior Metallurgical Engineer
    SGS North America
    Blue Island IL
    (708) 595-8734
    ------------------------------

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  • 3.  RE: Failure analysis on train wheel-axis

    Posted 12 days ago
    Hello Edward
    This lack of press-fit can be influenced by some heat treatment that the axis has soffered ?

    ------------------------------
    Giancarlo Sanchez Chavez
    UNSA
    Miraflores
    947822222
    ------------------------------

    Aeromat 2023 - Registration Now Open


  • 4.  RE: Failure analysis on train wheel-axis

    Posted 16 days ago
    Most of the time it's a metrology issue resulting in insufficient interference fit. Both in the axle and wheel and not just diameter but also taper and finish and lay. AAR has guidance on this I believe. But in retirement I don't have access to it.

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    Joe Epperson, FASM
    Senior Metallurgist, retired
    Waldorf, MD
    Joedirt3478@outlook.com
    ------------------------------

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  • 5.  RE: Failure analysis on train wheel-axis

    Posted 12 days ago
    Hello Joe
    Thank you for your reply. Do you have the link of AAR?

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    Giancarlo Sanchez Chavez
    UNSA
    Miraflores
    947822222
    ------------------------------

    Aeromat 2023 - Registration Now Open


  • 6.  RE: Failure analysis on train wheel-axis

    Posted 12 days ago
    Www.aar.org

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    Joe Epperson, FASM
    Senior Metallurgist, retired
    Waldorf, MD
    Joedirt3478@outlook.com
    ------------------------------

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  • 7.  RE: Failure analysis on train wheel-axis

    Posted 5 days ago
    Thank you

    ------------------------------
    Giancarlo Sanchez Chavez
    UNSA
    Miraflores
    947822222
    ------------------------------

    Aeromat 2023 - Registration Now Open


  • 8.  RE: Failure analysis on train wheel-axis

    Posted 16 days ago
    Yeah, that's likely a lower press tonnage than designed, and this one looks pretty bad. You might find out where the wheelset was assembled, and request the press fit curves from them, if they even have them. Compare this to whatever standard or local regulations state govern wheelsets for this use (freight, passenger, light rail, etc.) and see if it is different and by how much. See if a lubricant or anti-galling agent was applied to the surfaces, which might be allowed or disallowed.
    Also, dimensional measurements of the wheels and axles will make sure there wasn't something missing in the machining process. You could also check whether these were repurposed or original wheels and axles. Lastly, looking for signs of fretting, galling, and even cracking on the contacting (faying) surfaces. Good luck!

    ------------------------------
    Erik Mueller
    Materials Research Engineer
    National Transportation Safety Board
    Washington DC
    (202) 591-6359
    ------------------------------

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  • 9.  RE: Failure analysis on train wheel-axis

    Posted 12 days ago
    Hello Erik
    Thank for your post.
    Exactly the axle was repurposed and a new wheel was placed. How much and how this can influence in the disengaged?

    ------------------------------
    Giancarlo Sanchez Chavez
    UNSA
    Miraflores
    947822222
    ------------------------------

    Aeromat 2023 - Registration Now Open


  • 10.  RE: Failure analysis on train wheel-axis

    Posted 2 days ago
    Hi

    In case of new wheel replacement, one should go through the procedure recommended like condition of the shaft like worn out or within the tolerance for replacement etc.

    ------------------------------
    SESHUPRASAD RAO
    DIRECTOR
    METEXPERT METALURGICAL CONSULTANCY PVT LTD
    Milpitas CA
    +917829721305
    ------------------------------

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  • 11.  RE: Failure analysis on train wheel-axis

    Posted 16 days ago

    It appears to be from a freight car based on the axle geometry.   Multiple folks have commented on axle / wheel fits here, and that the AAR has new/ rebuild dimensional requirements.    Additionally I would make some basic determination as to whether the axle bearings ( both sides) here was also free to operate properly.   Bearing failures on axle assemblys are the most common failure modes here.  With freight cars the they can often sit for months or even years seeing little operational miles or the inverse seeing lots of miles prior to proper maintenance.  





    ------------------------------
    Anthony Giammarise
    consulting metallurgist
    MOSTLY METALS
    Erie PA
    ------------------------------

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  • 12.  RE: Failure analysis on train wheel-axis

    Posted 2 days ago
    Hi Gian 

    I recommend you to go for intial why why anlysis with user interface and next stage at the level of data records on manufacturing then you will find Route cause. Arbitrarily there can be many reasons for failures. This may be a Metallurgical failure, Mechanical failure, System failure, Equipement design failure etc. We have to go on elimination basis. I advise you to go as per guidelines for Route Cause Analysis to exactly find the failure.

    ------------------------------
    SESHUPRASAD RAO
    DIRECTOR
    METEXPERT METALURGICAL CONSULTANCY PVT LTD
    Milpitas CA
    +917829721305
    ------------------------------

    Aeromat 2023 - Registration Now Open