Curve radius

Discussion in 'Track Planning' started by Matt Probst, Aug 25, 2002.

  1. Matt Probst

    Matt Probst Member

    Does any one know of a formula or math equation for determining a curve radius ON PAPER?. I don't have any of that fancy track planning software and the Atlas freeware track planning program is not very user friendly.

    Matt--Chocolatetown USA
  2. Vic

    Vic Active Member

    Hi Matt, There's a real easy solution to this that doesn't require any math.

    First you'll need some 1"=12" graph paper. I found mine at the local college bookstore. Places that sell supplies for architechs will have it too or you can draw your own and photocopy it.

    I don't know what scale you model in but CTT. Inc makes plastic templates for various scales and all you have to do is use the template to draw the curves on to the graph paper. The template's are already scaled out on a 1:12 ratio. For HO the part # is #5000. Your local hobby shop can probably order it from Walthers.

    Hope this helped.

    PS: Be sure to get 1"=12" paper....the kind that you find in pads at the Wal~Mart is 1"=10" otherwise you'll be off by 2"...the voice of experience speaks:eek: :D :D
  3. Gary Pfeil

    Gary Pfeil Active Member

    Matt, I use a scale of 3/4" = 1 foot. Then, 1/16" = 1". When drawing a 90 degree curve, say 30" radius, I simply measure 30/16" (1 7/8) from the end of the tangent line, make a dot there, then measure 1 7/8 again, at a right angle to the tangent line, and mark that. I just draw in a rough curve to connect the tangent to the second mark. I'm not one for exact scale drawings, they aren't needed. I allow 1 foot (3/4") for each turnout. This method will accurately let you know what will fit. It suffices in most cases. If you are trying to cram a lot of track in a little space, then a more to scale drawing should be made.


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