System dynamics modeling and experimental study of railway track with thermoelectric heater/generator in extreme weather conditions

This paper develops a novel railway fastener system with thermoelectric heater/generator to heat the rail pads with the clean and sustainable electric energy harvested from the ambient thermal radiation. Due to the extremely cold temperature in some areas, the varying dynamic properties of rail pads result in a potential threat to the safe operation of the railway track system. The proposed thermoelectric generator can be used to continuously supply sufficient clean electric power to heat the rail pad, ensuring the railway fastener work within a proper temperature range. The experimental results show that the thermoelectric generator can provide an electric power of 5.8 mW with a low temperature gradient of 8 degrees C, and the working temperature of the rail pads can be improved by an average of 9.5 degrees C with 4 heaters of 2.5 W, which is consistent with the theoretical results of the finite volume method by FloTHERM. A fractional derivative Zener model of the coupled vehicle-track system is established to investigate the random vibration of the railway track structure with and without the proposed intelligent fastener system, and the calculated results show that the peak amplitude of wheel-rail contact force changes from 1.37 kN/Hz to 2.34 kN/Hz; whereas the first dominant frequency varies from 56.8 Hz to 68.0 Hz. It indicates that the vibration of the coupled vehicle-track system can be reduced by 41.5% with the proposed fastener system in extreme cold weather conditions. (C) 2019 Elsevier Ltd. All rights reserved.