Analysis of traction electrical equipment failures in ES104 “Finist” DC high-speed trains

Objective: in 2025, ES104-series high-speed electric trains equipped with asynchronous traction drives commenced regular service on routes operated by the Oktyabrskaya Railway. During this period, a multiple malfunctions of traction electrical equipment – primarily asynchronous traction motors and traction converters – were recorded. This paper analyses the types and underlying causes of asynchronous traction drive failures identified over a six-month monitoring period of ES104 electric train operation on the Oktyabrskaya Railway using maintenance and repair records. Methods: this study examines faults in the asynchronous traction-drive system of ES104 trains that precipitated failures of the asynchronous traction motors and traction converters. Results: analysis showed that asynchronous traction motor failures originate from insulation breakdowns in their stator windings, leading to reduced insulation resistance between the stator winding and motor housing, interphase short circuits within the winding, and open circuit (phase-break) faults of the stator winding. Failures of traction converters were primarily associated with malfunctions of the traction controller or the brake regulator controller. These observations highlight the imperative to improve the manufacturing quality of the electrical equipment in order to enhance its reliability. The study produced a set of recommendations for eliminating the identified defects. Practical significance: these findings are relevant for the advancement of manufacturing technologies for powerelectrical systems in electric rolling stock, as they address the primary operational problem facing contemporary high-speed ES104 series trains — recurrent failures of asynchronous traction motors and traction converters.