Track loading on Russian Railways under modern maintenance conditions

Abstract

Rail fasteners loading and its influence on the track deformability under modern maintenance conditions with increased cars axle loads is observed. The difference between oneand two-point wheelrail contact loading scheme is shown. The authors present the analysis of domestic and foreign methods of pads bench tests and show the necessity of carrying out tests imitating real (two-point contact) loading of pads. The bench test method for researching fastener loading and pad strain characteristics in a wide range of vertical and lateral loads under two-point contact scheme based on a number of field tests is presented. The results of static tests and following dynamic ones with cycling loading, which were carried out on a two-sleepers bench, are observed. Bench tests carried out by VNIIZHT and the analysis of the cyclic test methods showed the importance of fasteners tests with a real loading simulation making it possible to explain the causes of track gauge widening and decrease of track inclination, which considerably influences track stability and wear of the track and rolling stock.

Determination of rail deformations using fiber optic technologies

“…In this paper, approaches are developed that allow modeling and implementing a system for diagnosing rail strings based on fiber-optic measurement and data transmission systems [3]. Optical fiber in a protective sheath is proposed to be glued to the stripped side surface of the neck of the rail whip [4][5][6] and, according to the changes in the parameters of the transmitted light pulses, it can help to evaluate the deformation of the rail in real time. When a signal is transmitted over an optical fiber, it is attenuated, dispersed, nonlinear effects (self-modulation, cross-modulation, four-wave mixing, etc.)…”