Instruments and Systems: Monitoring, Control, and Diagnostics Annotation << Back Device for Automated Testing of the Quality of the Fit of a Small Gear on the Shaft of a Locomotive Traction Engine М.V. KOPANEV, A.V. PULTYAKOV, V.A. ALEKSEENKO, M.E. SKOROBOGATOV One of the main challenges facing the railway industry today is to ensure an ever-increasing volume of passenger and cargo transportation while unconditionally meeting safety requirements. To accomplish this task, reliable operation of the locomotive fl eet is required. One of the failures of locomotives, which negatively affects the safety of the transportation process, is the breakdown of a small gear from the shaft of a traction electric motor. To assess the quality of mounting a small gear on the shaft of a traction electric motor, many devices have been developed, one of which is devoted to the article. The article presents a general view of the automation device for checking the quality of landing of a small gear on the shaft of a locomotive traction engine with a description of its main components; the indicators by which the device evaluates the quality of landing (pressure acting on the piston surface in the stem cavity of a power hydraulic cylinder, a unifi ed DC output signal corresponding to the load applied to the gear) are considered; The flowchart of the algorithm for completing the verification process is presented, which consists of three main stages (performing preparatory operations, conducting tests, performing fi nal operations). The main advantages of the developed device are: mobility, compactness and automated processing of measurement results. Keywords: Automation device, fi tting, gear, shaft, quality, check, hydraulic cylinder. DOI: 10.25791/pribor.4.2025.1571 Pp. 01-08.