Minimum Radius of Model Train Track Curves 



For some time now I have
been trying to work out a mathematical formula to give and indication of
the "Minimum Radius of Track curves" so that for say "G" or G1" locos I could
use as a starting point to determine what curve of track I could layout in
my garage and then test a loco on a piece of track set to that
calculation.
I have thought that the minimum curve radius must be related to :


Looking through Tubal Cain's book "Model Engineer's Handbook" I came across the formula relating the above mentioned items and introducing to me a term that I had not come across before VERSIN !!!.  


Then I thought how on earth do I transpose the formula, as it was a long time ago that I did "A" level maths at school so I emailed a radio amateur friend who took a look at it and came up with:  


It works out curves as I would have expected !  