This article was prompted by a large number of failures of the rubber-cord coupling for traction drive of ER2T series electric multiple unit (EMU) trains of the. The number of failures was summarized on the basis of the railway company JSC "Pasažieru vilciens", operating on the Latvian railway, reports on unscheduled repairs for the period from 2015 till 2020. In the presented article, we will discuss the determination of the reasons for ER2T series EMU trains rubber-cord coupling failure. The object under study was a rubber-cord coupling, which was out of order and taken after unscheduled repair from a motor car No. 2207-02. Based on the results of the test trial on 23.07.2020, the heating temperature of eight rubber-cord couplings was determined on four carriages of the ER2T series train No. 7115R on the route Riga – Jelgava. The shear stress τs and the radial load Fr acting on the coupling during movement are determined. In the RTU laboratory, the geometric dimensions of the coupling have been determined, the influence of the lubricant action and the temperature effect on the mechanical properties of rubber has been investigated. Based on the research results, the reasons for the failure of the traction drive rubber-cord coupling were analyzed, and conclusions were drawn about its possible failure. The research results are compared with standard requirements.