help with helix

denm31 Jul 30, 2015

  1. denm31

    denm31 TrainBoard Member

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    hello
    I need some help.( professional help but that is besides the point). I have built a helix using atlas code 55 flex track . the rest of my layout is all Kato uni-track . this was my first attempt at using flex track. all the while building the helix I ran my locos and other rolling stock back and forth every turn I constructed and did not have any issues. now that is installed on the layout all my locos are derailing at several connections. I used rail joiners and solder at every connection. I only soldered on the out side of every rail. if I had a high spot I hit with a grinding stone. anyone have any ideas on how to resolve this without disassembling the whole thing.
    thank you dennis
     
  2. mtntrainman

    mtntrainman TrainBoard Supporter

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    What is the radius of your helix ?
    Is it just locomotives that derail...or whole trains ?
    Are they derailing to the outside or inside of the curve ?
    Is it always at the same place on the track ?
     
    Last edited: Jul 30, 2015
  3. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    Does it happen at identifiable points? Have you checked track gauge? Flex track can narrow, especially tighter radius. At least check gauge at every place where there has been soldering. Be certain where you soldered it has not produced a slight kink.
     
  4. John Moore

    John Moore TrainBoard Supporter

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    Track gauge was mentioned and can be a very distinct possibility. If you did not use heat sinks on the rails, both ends of the rails being soldered, then a heat build up could have melted the ties slightly causing the rails to go slightly out of gauge at that point. Also radius could be an issue if you did not use a template to insure that the radius on the flex stayed within your operational needs. Getting the radius too tight on just a few inches of flex can cause derailments especially if one is running 6 axle locos. 4 axle locos are a little more forgiving. If you have a four axle loco see if that will run the helix without derailing. If it does maybe then you need to widen out the radius some for the bigger power.
     
    Last edited: Jul 31, 2015
  5. denm31

    denm31 TrainBoard Member

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  6. denm31

    denm31 TrainBoard Member

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    radius is 18 inches. it is just locos as far as I can see at first it was my Kato f3's and f7's but now my SD 40 and SD 90 are also doing it . if I set the speed for the SD's at crawl the make it up. tried all rolling stock backwards and forwards by hand and they don't derail. but I also have to wonder if it can be the heat . I live in phoenix and the layout is in the garage constant temp of 90 to a 100 plus.
     
  7. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    Air temperature and humidity as well can definitely cause troubles. You may be suffering the model railroad version of sun kinks.
     
  8. John Moore

    John Moore TrainBoard Supporter

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    Could be heat since the rails will expand and contract some with temperature. If the rails were laid in the cooler times and ends butted up to each other with no expansion joint then it can be likely that expansion has pushed some out of gauge. My small layout has some expansion joints at various points and mine is kept in a conditioned environment. Can be especially true if the rail work was done in 70 or 80 degree heat and now you are dealing with 100 or more deg. Problem may persist if the rails do not return to previous positions when the temp drops. May be facing the issue of having to remove and relay the rails leaving a few places just joined by rail joiners rather than solder and a small gap at each location for expansion. Enough small gaps depending on the total length of the run would solve that issue if it is that. I would still want to take an NMRA track gauge to the entire track area before I would even think about that. Also there is the possibility that a small bit of solder could be interfering with the loco wheel flanges that a lighter car might pass over but then the gauge would pick that up.
     
  9. mtntrainman

    mtntrainman TrainBoard Supporter

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    Like John said...heat expansion could be a culprit. I know what Arizona sun and heat can do...even up here in the mountains. Your low temps in the valley are our highs up here. We get in the 90's during the day on a lot of occasions...making it over 100 in the closed up interior of THE RV . Last summer...I had my first 'ski jump' develope out in THE RV. Using Unitrack and I hadnt checked the track. By the time the locomotive got to the end of the main thru the yard and hit that 1/4 inch vertical heat kink....it launched the locomotive right off the main. Heat kinks can go up or sideways...whichever is the path of least resistance. If you discover heat kinks and your track is already fastened down...I would take a Dremil with cutting disk and cut some heat gaps mid way on the flex. Just DONT cut them right accross from each other. I have heard the best bet is to offset the gaps by maybe 6 ties within the same section. YMMV
     
  10. porkypine52

    porkypine52 TrainBoard Member

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    Check the GAUGE EVERYWHERE. Can you get to the trackwork on the whole helix? If you can, take an MTL single truck and run it over the line using a single finger on the bolster. If you have track problems, you should be able to feel where they are when the truck bumps or derails. I don't have the heat problems here in So. Indiana, but your trackwork on ANY Helix needs to be BULLETPROOF. Good enough won't do!!!
     
  11. bill pearce

    bill pearce TrainBoard Member

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    What is the material the helix is made of? Wood? If so that could be your problem. Thermal expansion and contraction are imperceptable for nickle silver rail in habitable climates, but expansion/contraction in extreme climates like Phoenix are a real problem with temperature (and more importantly humidity) rise and fall. For many years, modelers have been led to believe that our rail expands and contracts under normal domestic conditions without scientific backing. Perhaps junk science started with us.
     
  12. denm31

    denm31 TrainBoard Member

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    the base is made of 1/2 mdf . which i used hot glue and gorilla wood glue and 1 inch brads from my nail gun.but none of the de railing is happening near the joints as far as i can tell. i think i am going to have to chalk this one up to a learning experience.
    I think i am going to have to break down and get the kato curved double track and tear out the flex track. don't have the time to go over the thing. thanks to every one for the input
     
  13. ntbn1

    ntbn1 TrainBoard Member

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    I had similar problems and identified the issue as expansion/contraction of the rails. I expanded my helix from a circle to an oval. Soldered the curves and left expansion joints ( non- soldered joints) in the straight sections. It seems to have eliminated the derailment problem. I have very smooth curves with no kinks.

    Dave G
    Cache Valley & Northern RR
     
    BoxcabE50 likes this.
  14. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    Nice idea!
     
  15. CarlH

    CarlH TrainBoard Member

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    My Kato F3's are very touchy about vertical grade transitions, and I have put many vertical grade transitions in my layout, just for the fun of it. The Kato F3 trucks just don't "give" like some of my other locos, and it makes it so they are just as picky about vertical grade transitions as some 12-wheel diesel locos that I have.

    Do the Kato F3's do any better if you run them backwards through the problem areas?
     

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