Identification of High-Speed Rail Ballast Flight Risk Factors and Risk Mitigation Strategies – Final Report Saat, M.R., F. Bedini Jacobini, E. Tutumluer and C.P.L. Barkan. 2015. Identification of High-Speed Rail Ballast Flight Risk Factors and Risk Mitigation Strategies - Final Report. U.S. Department of Transportation, Federal Railroad Administration, Washington, DC, pp. 76, DOT/FRA/ORD-15/03. Files Identification of High-Speed Rail Ballast Flight Risk Factors and Risk Mitigation Strategies – Final Report - Full Text (PDF) Categories Safety and Risk