Abstract: The paper draws attention to the insufficient effectiveness of the methods used so far in the railway industry for shaping the track axis in the horizontal plane. It is hypothesized that the possibility of a radical improvement in the situation is provided by the method of continuous GPS satellite measurements, applied by a research team from the Gdańsk University of Technology.The general characteristics of satellite measurements are presented, and the course of the conducted field research is described. The completed studies have shown that the use of GPS measurement technology enables very precise determination of data for designing railway line modernization (main directions and route deflection angle). They allow for the assessment of the position of straight track sections, as well as the reconstruction of areas where the route direction changes.
The assumptions of a new method for designing the track axis (in a local coordinate system), adapted to satellite measurement technology, are presented.
1. INTRODUCTION
One of the key problems occurring in railway tracks and directly related to the issue of train speeds is the methodology of track axis adjustment [2].
Adjusting the railway track axis is essentially the re-designing and staking out of its axis, primarily to remove existing horizontal deformations or to correct an improper geometric layout.
There is a whole range of methods that allow for the determination of transverse displacement values of the track grid; these are used by automatic tampers performing the geometric adjustment process. The vast majority of these methods are based on determining the shape of the existing track axis in an indirect way, based on
versine measurements [8]. Design activities are therefore carried out not on the actual layout, but on its horizontal transformation. This leads to serious inaccuracies.
This became apparent during the introduction of increasingly sophisticated track machines, including, above all, automatic tampers equipped with internal measurement bases for the track geometric layout [5]. As a result of design inaccuracies, many circular curves have been distorted, especially in the area of transition curves. On (theoretically) straight sections adjacent to these curves, reverse curvatures have appeared, most often resulting from an incorrect determination of the actual route deflection angle for the purposes of the adjustment project. (…)
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Source: Logistyka Magazine