Thank you! In the past, I must've used 2-22" then 3-18" then 2-22" pieces. I thought we tried that the other day, but I'll try it again.
Good subject. For a little more insight (or geometry, as the case may be
)..................
As most folks know, a full circle is generally defined as 360°.
22" radius track sections are each 22-1/2° (or 16 pieces to a full circle). Therefore, 4 of these track sections add up to 90°.
18" radius track sections, and 15" radius too, are each 30° (or 12 pieces to a full circle). Therefore, 3 of these track sections add up to 90°.
And there you have it - 90° plus 90° equals 180°, or a half of a circle, regardless of the two different radii we used here!
In addition, one could also make use of 1/2 and 1/3 sections of curved track sections if available in the various radii, in order to come up with a total of 180°. For example, one could start with one 22' radius curve (22-1/2°), then one 18" radius curve (30°), then two sections and a half section of 15" radius curves (75° total), then an 18" radius curve (30°), then finish with a 22" radius curve (22-1/2°). Total: 180°, or a half a circle.
And for that matter, you can also use the same logic for a quarter of a circle (90°) or any other portion of a circle you want to use.
And another neat thing using the aforementioned example - entering a curve and leaving a curve with a larger radius than the main curve is a GOOD thing - it's known as an "easement", or "easements". The real railroads do this. They start into the curve by slowly inducing a curve, then spiraling down to a minimum radius, then maybe (or maybe not) going through this fixed minimum radius, then spiraling back up and out of the curve. Model trains can somewhat replicate this with sectional curved tracks of various radii, or maybe even better yet using flex track. Either way, our model trains can run better and look better too when using easements, as opposed to slam-dunking directly into and out of one, single fixed radius of curved track, as many layouts do.
