# How is the radius on track measured?

Discussion in 'FAQs' started by Fusion, Jan 6, 2006.

1. ### FusionNew Member

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I'm planning out my layout and would like to know how to measure the track. For example on Atlas track packaging it says 12.5" Radius/Full Curve. What does this mean exactly? And on that note, if I use Atlas Flex Track should there be a minimum radius curve that has to be followed?
2. ### 60103Pooh Bah

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Fusion:
Radius is measured from the centre of the circle to the centerline of the track. This makes it easier to draw track plans, but you have to remember to add space for the bits of track on the outside.
"full curve" is a marketing term. Someone decides that a certain number of sections will make a circle -- usually 12 or 8, sometimes 6, 4, or 2! That size becomes a "full" curve. Half that size becomes a "half" curve, then other fractions. Often wider curves than minimum will be allowed to take more than 12 sections to a circle -- usually this keeps them about the length of the first full curve, and keeps tha packaging the same size. (Did they tell you I'm cynical?)
Minimum radius is an artistic decision. Well, it depends on what type of lcomotives and cars you plan to run and how much space you can occupy. 12" in N gauge should allow you to run up to middling sized diesels and steam locomotives with 6 drivers, possibly 8. (will depend; some highly detailed locos may need much wider curves.) I ran full length passenger cars around 12", but if they were spaced closer together it would have required wider.

Atlas flex track should curve down to something much sharper than you could possibly want. When Peco Streamline first came out, they showed the track twisted into spirals and tied into knots.
3. ### FusionNew Member

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Thanks 60103. Now it's making sense.

Now on a curve how far appart will multiple tracks in N scale have to be? I've read some posts on this but didn't find a definitive answer. I think someone said 1 1/4" or was it 1 1/2" from centre to centre of the track.

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