MEASUREMENT AND ANALYSIS OF THE DYNAMIC EFFECTS ON THE CROSSINGS
Last modified: 2017-02-28
The turnouts are one of the key points of the railway routes. In particular, turnouts in the main tracks are passed relatively high speed. This paper is focused on measurement and analysis of dynamic effects on railway turnouts. The main rail turnouts which are passed in speed of 160 km·h-1 and with different wear condition were selected. Attention was focused mainly on the crossing panel of the turnout, where the highest dynamic impacts occur. The turnout was measured twice: before and after frog repair by welding. The point of the paper is comparison of the crossing part of turnout in term of dynamic behaviour and assessment of influence of the transition geometry (wearing depth) on dynamic effects. Because dynamic impact from the wheel sets during the transition from the wing rail to the nose of the crossing depending on the quality of the transition geometry and also on the overall stiffness of the rail superstructure, the appropriate methodology of the measurement was designed. The methodology is designed for in situ measurement in condition of full operation and consists of two parts. Measuring of vibration and measuring of shifts of the bearers in the crossing panel. Piezoelectric vibration acceleration sensors (the accelerometers) were attached to plastic handles and glued to the cleaned surface of the measured structure. Three-axis accelerometer B&K 4524 B001 was placed at the foot of the wing rail, five accelerometers B&K 4507 B001 were placed at the bearer and one accelerometer B&K 4507 B004 was placed at the measuring bar embedded in the ballast. Shifts of the bearers ware measured by inductive displacement sensors HBM WA-10 T which were attached through magnetic holders to special frames. Frames are made of two steel bars embedded in the structural layers of subgrade and steel cross members connecting the two poles. This method created referential zero-point shift. For evaluation of measured data were used time analysis, frequency analysis using the amplitude spectrum and time-frequency analysis.
Turnout, crossing panel, vibration measurement, measuring of shifts, frequency analysis, time-frequency analysis