Diameter of curves

Discussion in 'FAQs' started by CSX, Sep 22, 2005.

  1. CSX

    CSX Member

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    For my outdoor railway I am getting an Aristo-Craft CSX SD-45 locomotive. It needs 8 foot diameter curves. What is the degree of curve for that?
  2. jetrock

    jetrock Member

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    180 degrees?
  3. ezdays

    ezdays Out AZ way

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    Not sure what you're asking here. jetrock is right, 180° for the semicircle, regardless of the diameter or radius. If that's not what you mean, then please be a bit more specific so you can get the answer you need.
  4. MasonJar

    MasonJar It's not rocket surgery

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    See http://www.du.edu/~jcalvert/railway/degcurv.htm

    Degree of curvature as an alternate measurement for such small circles (i.e. your 8 foot diameter / 4 foot radius) is almost meaningless in railroad terms. The degree of curvature is/was based on a 100' section of the curve called a chord. It is much easier to refer to radius. However, you can do the math for a smaller circle if needed.

    For example, a 1 degree curve (based on the 100' chord) has a radius of about 1 mile. Even a relatively sharp real world railroad curve of 6 degrees has a radius of about 1000 feet.

    The above info and link is from this page - http://www.du.edu/~jcalvert/railway/railhom.htm - an interesting reference...!

    Andrew
  5. CSX

    CSX Member

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    Here, maybe this will help a bit. What does it mean when it says the train needs 8 foot diameter curves? I don't want to buy the wrong track for my outdoor railway.
  6. ezdays

    ezdays Out AZ way

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    OK, it means just that. If you put a peg into the ground and tie a 4' string to it, and trace out the circle the end of the string makes around the peg, that's an 8' diameter. Now if you were working in HO or N scale, you could just go out and buy flextrack and form it to fit the curve. In G scale, I don't know if there is flextrack, if not, you should be able to buy curved sections that would conform to a 4' radius. Someone into G scale would have to tell you how they are marked. That's the best I can do.
  7. CSX

    CSX Member

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    That would mean buying the track first though?
  8. Gary Pfeil

    Gary Pfeil Active Member

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    LGB and Aristocraft curved track come in radius's named in diameter, not radius. You need 8' minimum, next size is 10'

    Gary
  9. CSX

    CSX Member

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    I am doing a layout, so how many peices of track come in a diameter?
  10. 60103

    60103 Pooh Bah

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    You mean in a circle? The number of pieces varies depending on the radius/diameter and the manufacurer. Also, some provide double or larger pieces, and half and shorter pieces.
    A full circle of 8 foot diameter requires 8 x 3.1416 feet of track. (The arithemtic is left as an exercise for the student.)
  11. SLUSSERS

    SLUSSERS New Member

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    How many pieces of track is dependent upon the degree of the section of track not the radius. Some sectional track of the same radius may be made in 15deg., 30 deg., or 45 deg. sections. If the track sections are 15degs., 30degs. or 45 degs., it would take 180 degrees (for one half of a circle)divided by the degree of the track sections.
    Examples: 180/15 = 12 sections of track to make a half circle
    180/30 = 6 " " " " " " " "
    180/45 = 4 " " " " " " " "

    Hope this helps. :thumb: :thumb:
  12. Gary Pfeil

    Gary Pfeil Active Member

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    I suggest checking the Aristocraft website. My guess would be 16 pcs., but I don't know. You can just ask whomever you buy from.
  13. Russ Bellinis

    Russ Bellinis Active Member

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    They do make flex track for "g" scale, but it takes a special tool to bend it.