High-speed railway ballast flight mechanism analysis and risk management - A literature review

Ballast flight is a significant safety problem for high-speed ballasted tracks. In spite of the many relevant prior studies, a comprehensive review of the mechanism, recent developments, and critical issues with regards to ballast flight has remained missing. This paper, therefore, offers a general overview on the state of the art and practice in ballast flight risk management while encompassing the mechanism, influencing factors, analytical and engineering methods, risk mitigation strategies, etc. Herein, the problem of ballast flight is emphasized to be associated with the train speed, track response, ballast profile, and aggregate physical characteristics. Experiments and dynamic analysis, and reliability risk assessment are highlighted as research methods commonly used to analyze the mechanism and influencing factors of ballast flight. Technical solutions and risk management are furthermore presented as known strategies to mitigate the ballast flight problem. Through this review, researchers and practitioners are provided a reliable reference for investigating ballast flight and for developing implementation solutions to mitigate the associated risks. (C) 2019 Elsevier Ltd. All rights reserved.