TY JOUR TI A comparative analysis of the causes underlying unscheduled repairs of passenger railway cars KW passenger railway car KW unscheduled repair KW ongoing uncoupling repair (OUR) KW mileage KW railway car age KW operational efficiency JO Bulletin of scientific research results AU Vishnyakov, I.A. AU Evseev, D.G. PY 2026 IS 2026 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"