TY JOUR TI Laboratory Tests to Investigate the Vibration Isolation Properties of Elastic Under-Ballast Materials KW Vibration isolation KW under-ballast mats KW vibrodynamic impact KW vibration transmissibility KW complex elastic modulus KW loss factor KW natural oscillation frequency JO Bulletin of scientific research results AU Maslov, N.K. AU Val'ceva, T.Y. AU Saydaliev, A.A. PY 2025 IS 2025 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"