Fw: (erielack) Univ Of Akron Erie Lackawanna Archives

["Schuyler G Larrabee" <sgl2_@_ix.netcom.com>]

An individual more knowledgeable about these matters than I observed, about
my statement that:

> I believe I am correct in saying that the degree of curvature
> indicates the number of degrees the curve has changed one's heading
> after 100' of line.  (I might not be correct on that . . .)

it is more like this:


> Your description of degrees of curvature is essentially correct.  It is
> actually the "central angle," as part of the 360 degrees of a circle, that
> is created by a 100 ft. chord taken along the center line of the curve,
but
> it turns out by the laws of geometry that what you describe also works,
and
> that is how track workers do their measurements in the field.  There is
also
> another coincidence, and that is that the deflection from the track to the
> chord at its central point, in inches (this is coming from memory, so
don't
> hold me to it), is equal to the degrees of curvature, making the track
> worker's job even easier!  The process is called string-lining, I believe.

Offered in the event that some of you might like to know this.  Isn't there
a real civil engineer on this list who can stop laughing long enough to tell
us if we're wrong?  Or are we right?

SGL

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