TY JOUR TI Engineering Methodology for Determining EMF in Idling DC Traction Substations KW Traction substations KW direct current system KW heavy-duty freight traffic KW EMF in idling KW electric energy losses JO Bulletin of scientific research results AU Varicheva, V.V. AU Siukaev, T.Z. AU Dudin, B.A. PY 2025 IS 2025 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"