Regular Article

Experimental study of flying ballast at high speed railway applying track vibration

School of Railway Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

^* e-mail: mrtalaee@iust.ac.ir

Received: 20 July 2019
Accepted: 27 March 2020

Abstract

In this paper the complete approach is introduced for study of Ballast flying in wind tunnel considering track vibrations and aerodynamic loads. The air velocity profile under high speed train with speed of 300 km/h is introduced using an analytical approach and the intensity of under train wind is defined. About 50 kg of Iranian high speed railway ballast is adopted by random sampling and classified according to mass and aerodynamic shape. The critical velocities of ballast moving are measured by wind tunnel for all classification to obtain the ballast flying probability factor (BFPF) at two modes of with and without track vibration. Also, the conventional ballast flying risk mitigation methods in wind tunnel are reviewed and a new strategy for ballast flying risk mitigation is introduced and tested, based on the design of track surface by a special sieved group of ballasts with minimum flying probability factor. Results show that the BFPF increases in presence of vibration and the minimum value of BFPF is occurred at mass range of 150–200 g. It's stated that application of this group on the track surface may prevent from ballast flying due to passing of train with maximum speeds of 300 km/h.