RA> This is "standard" nomenclature for curve radii (on US railroads,
RA> at least). The angle quoted is the angle between the track and a
RA> 100 foot long chord across the curve.
GP>      Just to clarify your comments (I have been called
GP> pedantic before now :-)
GP> is the angle you quote above, the complete arc of the curve,
GP> or the angle of the track end to the chord. This makes a 2:1
GP> difference to the result.
As I understand it, it is the angle between the chord and the arc.
(What's a "versine"? Thought I'd had all the plane geometry
there is... ) :)
GP>      The versine/chord measurement is easy for anyone with a string, tape
GP> measure and radius manual to check. Do you know how the
GP>angle was/is measured,
GP> the accuracy of measurement of the angle would have to be very precise, a
GP> minute or twos error would be a big change in radius.
I doubt anyone really woried. You see, the Friends of the East
Broad Top RR has obtained complete right-of-way maps for the RR,
circa 1917, drawn by the RR itself. They show curves' radii. ;)
Reggie Arford
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 X SLMR 2.1a X "A man-o-war is the best ambassador." - Oliver Cromwell
--- Maximus 3.01
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