TY JOUR TI Selection of loading schemes for assessing the fatigue resistance of frame elements of flat cars KW flat cars KW fatigue resistance safety factor KW crack resistance KW load spectrum JO Proceedings of Petersburg Transport University AU Cyganskaya, L.V. AU Smirnov, A.N. AU Beyn, D.G. PY 2024 IS 21 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"