RAILWAYS TRANSITIONS SPLINES WITH G3 CONTACTS

Abstract

The paper is a continuation of earlier concerns regarding the roads/railways transitions ends contacts. If in the previous approaches G2 contacts were treated, this paper discuss how to integrate Excel Solver and a low priced CAGD environment (AutoCAD clone) in order to draw G3 contacts railways transition curves, with super-linear monotonic variation of the curvature, using the AutoCAD/IntelliCAD implementation of NURBS (Non- Uniform Rational Basic-Spline). In order to avoid unwanted local alteration of transition shape, the paper uses the particular case of non-uniform non-rational B-splines (NUBS) without interior knots, that is Bézier splines in fact. Besides reaching the highest possible quality level of the ends contacts, these splines are very advantageous when replace the intermediate cubic parabolas of