Speed Matching & Consist

TexasRailroader Dec 29, 2017

  1. TexasRailroader

    TexasRailroader TrainBoard Member

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    So...
    Do you speed match while in consist mode or not?
     
  2. jwb3

    jwb3 TrainBoard Member

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    I'm not completely sure what you mean. As far as I can tell, the only good way to speed match is to put two locos into a consist and see which one is faster, then adjust CVs to get them to match speeds more closely. So yes, that's how I do it.
     
  3. RBrodzinsky

    RBrodzinsky November 18, 2022 Staff Member TrainBoard Supporter In Memoriam

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    I do my speed matching using a speedometer. I take the slowest performing loco and set up the speed curve I want. Then I measure the speed at (using 28 step mode) steps 1, 7, 14, 21 and 28. I then adjust the other locos for the consist to have the same speeds at these steps. Usually this is all that is needed.
     
  4. hoyden

    hoyden TrainBoard Supporter

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    I've used the min, mid, max speed CV's. Having a two track main I can run locomotives side by side to verify their speed. My mid speed setting corresponds to about 30 mph and max speed about 50 mph, measured with the JMRI speedometer.
     
  5. TexasRailroader

    TexasRailroader TrainBoard Member

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    When you release the consist do the locos return to their original configuration?
     
  6. RBrodzinsky

    RBrodzinsky November 18, 2022 Staff Member TrainBoard Supporter In Memoriam

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    Speed tables (whether the full table or Vmin/mid/max) are independent of whether in a consist or not. Once set, that is how your loco reacts to the throttle
     
  7. Greg Elmassian

    Greg Elmassian TrainBoard Member

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    I actually do custom speed tables for all locos, and map the speed step to the scale miles per hour. Then any loco can be consisted with any other loco. The other benefit, if I am going SS 35, then the loco is actually going 35 smph.

    I use a speedometer on a loop of track to measure, and modify the speed table in JMRI, so I can also save the configuration, and also restore the table easily in case I'm using spastic decoders that have weird math in their speed table (TCS decoder)

    (I flatten out the speed table above prototype top speed... so no loco actually goes over prototype scale speed)

    Greg
     
    Mark Watson and Northern Pacific like this.
  8. hoyden

    hoyden TrainBoard Supporter

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    I had problems with TCS decoders where the speed jumped significantly over a single step. My workaround was to use min/mid/max. Is there a better solution?
     
  9. Greg Elmassian

    Greg Elmassian TrainBoard Member

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    no that is the best solution.... i got rid of all my tcs decoders in z scale and went digitrax. They all seem to have this issue, which must be some internal math error.

    Clearly TCS is not interested in fixing it, you can find references to this problem in many places.

    Sad, since otherwise a nice decoder.

    Greg
     
  10. hoyden

    hoyden TrainBoard Supporter

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    Well, dang! After starting with Digitrax, then I switched to TCS decoders because Digitrax momentum, even at maximum value 31, trains accelerated from stop to maximum speed in about 10 seconds. TCS decoders allowed much longer accel/decel times.
     
  11. Greg Elmassian

    Greg Elmassian TrainBoard Member

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    I prefer Zimo in the smaller scales, digitrax I use in Z in the cases where you use a "drop in" just for convenience.

    Greg
     
  12. eforbes

    eforbes New Member

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    When you talk adjusting cvs are you talking forward trim cvs?
     
  13. Greg Elmassian

    Greg Elmassian TrainBoard Member

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    I don't think you were asking me, I use custom speed tables.


    Set Vmin and Vmax and then Vmid if you have it.

    Then, tweak with "trim" or "kickstart" stuff last.

    Greg
     
  14. eforbes

    eforbes New Member

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    I was kinda, yeah i know jmri has the speed tables but i do not have a laptop yet to bring out to the layout. I bring them in and try and tune them on my test track been pretty good so far. But really need to get the speedometer thing, it is the fastest. i eventually want to do what you did and spped table them all so you can consist with any locomotive you have. Thanks for the info.
     
  15. Mark Watson

    Mark Watson TrainBoard Member

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    Allow me to recommend the Boulder Creek Engineering "Rollby" Onboard Speedometer.
    A unit is inserted inside a boxcar shell and it turns your phone/tablet into a real-time speedometer/odometer display!

    Being real-time means you can fine-tune your speed while seeing direct immediate results, rather than doing one adjustment then waiting for the unit to circle back through the Accutrack, then the second adjustment, and waiting for the unit to circle back to the Accutrack again.

     
    eforbes likes this.
  16. eforbes

    eforbes New Member

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    Wow thanks!!
     

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