TY JOUR TI Electrothermal Model of an AC Catenary and Mechanisms of Ice Melting under an Autotransformer Traction Power Supply System KW railway KW catenary KW autotransformer traction power supply system KW ice accretion KW non-uniform icing KW finite element method JO Bulletin of scientific research results AU LI, I.. AU Vikulov, I.P. PY 2026 IS 2026 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"