TY JOUR TI Development of a Pricing Model for Piggyback Transportation in the Railway Transport System of Uzbekistan KW Piggyback traffic KW tariff model KW railway transport KW logistics KW economic and mathematical modelling JO Proceedings of Petersburg Transport University AU Muhamedova, Z.G. AU Ahmedov, S.H. PY 2025 IS 22 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"