New Transition Curve Adapted to Railway Operational Requirements

• Published in: Journal of surveying engineering 2019-08, Vol.145 (3)
• Main Author: Koc, Wladyslaw
• Format: Article
• Language: English
• Subjects: Curvature; Curves; Differential equations; Railway engineering; Railway tracks; Technical Papers
• ISSN: 0733-9453; 1943-5428
• DOI: 10.1061/(ASCE)SU.1943-5428.0000284

AbstractThis paper points to the limited possibilities of improving the existing situation of transition curves used in geometric layouts of the railway track. Difficulties in the practical implementation and maintenance of very small horizontal ordinates of the transition curve and the ordinates of the gradient due to cant in the initial section, appearing on smooth transition curves, were indicated. The main reason for this was the excessive smoothing of the curvature in their initial section. Employing the method of curvature identification by differential equations, a new form of the curve was obtained, referred to as the smoothed transition curve. A definite advantage of this curve was shown, from the implementation point of view, over representing the smooth transition curves of the Bloss curve and the parametric curve. It seems that it could successfully compete with the commonly used clothoid, to which it is similar in the initial section, while it differs significantly along its further length, especially in the final section, where it provides a gentle entry from the transition curve into a circular arc.