... have a small spreadsheet, which I wanted to post for those who may find it useful and found I could not post it last night. For a given Radius curve, Chord and Versine, if you know two of them it will calculate the third. It is very easy to use. I will try again later. Regards Tony. posted: 28 Oct 2014 14:03 from: Martin Wynne Hi Tony, XLS spreadsheet files can now be attached here. However, calculating versines can be done directly in Templot: 2_280857_140000000.png The dummy vehicle clearance mouse action can be used to measure the centre axle side-play needed on 6-wheel vehicles at different radii. 1. set the control template to the desired radius. 2. set the body length to match the wheelbase (dimensions... button). 3. set the body width to match the track gauge. The clearance marker can then be adjusted by mouse action to align with the outer rail. Read the versine dimension as the clearance showing (in prototype inches): ...