EZ Track Curve radii sizing for the new guy

[OldNnew]

I'm new to N and am confused by the Bachmann EZ-track radii sizes quoted online.  I need to buy more and see 11.25", 15" and 19" quoted, but don't understand what that means.   I have two different sizes in hand right now (used, so no packaging to tell me the radii size).  One yields a radius of just under 2 feet and the other just under 3 feet when I hook them together.

Can someone please set me straight on this curve radii sizing thing so I know what to buy?  Also, is there a good website which sells EZ-track in quantity at a decent discount?

Thanks a bunch to you experienced hands for your help on this!!

[Robert Grace]

I think you might be confusing radius with diameter. If you have 19" radii track, that yields a 38" diameter loop. radius x 2 = diameter. 15" radius would yield a 30" diameter (or just under three feet as you say). 11.25" radii put together would yield a 22.5" loop. Diameter is measured from the center of the track--midpoint between the rails.

[OldNnew]

You hit it right on the head Bob.  Can't believe I'd forgotten the difference between radius and diameter.  Thanks a bunch!!      M

[James in FL]

Turn a section of EZ track upside down.
The degree of curvature as well as the radius will be embossed there along with other information (Part and patent #’s, etc.).
AFAIK... In N scale, B’mann only produces two different curve sections, the 11.25r and the 19r.
If you have the real estate, go with the 19r. wherever possible/practical.