TECHNIQUES OF ADVANCED DESIGN OF RAILWAY TRACK GEOMETRICAL LAYOUTS

The paper systematizes the currently in use design methods of railway track geometrical layouts. The methods have been divided into two basic groups: those based on the design of the curvature, and the method of direct determination of the system ordinates. From the point of view of the calculation technique applied to each of these groups there have been distinguished symbol calculation technique and numerical calculation technique. In analyzing the methods related to design of the curvature of the system, particular attention was concentrated on the differential equation method as the most universal one. There has been carried out an analysis of the incorrectly determined system ordinates resulting from the operation of a simplified curvature formula to the symbol calculation technique. In this case a significant improvement of the accuracy was possible by taking advantage of the operational calculus. In the numerical calculation technique attention was drawn to the use of genetic algorithms. The methods of direct determination of the system ordinates by use of the symbol calculation technique are based on finding a solution in the form of explicit function y(x). An identification of the problem has been presented by means of differential equations. The problem of monotonicity can be explained either by searching for a parametric family solution or by an analysis of parameters of full solution. There have been pointed out some constraints connected with the application of solutions based on higher order polynomials. In the numerical calculation technique attention has been paid to the determination of the geometrical layout ordinates by use of evolutionary programming. For the covering abstract see ITRD E123761.