The technical equipment of modern trolleybuses (increased power of traction motors, regenerative-rheostatic braking, anti-slip and anti-lock systems, an on-board computer for monitoring and controlling the operation of the traction drive, GLONASS satellite systems, Internet access) increases the requirements for the quality of electrical energy and the electromagnetic compatibility of the installed equipment. In the course of the study, the electrical performance of the trolleybus traction asynchronous motor (voltage, current, voltage sinusoidal shape, total coefficient of harmonic voltage components) has been analyzed. Due to difficulties in the supply of foreign electrical equipment, primarily power electronics elements used to control the operation of the traction motor, there is an increasing need to improve measures for the maintenance of trolleybuses to increase the reliability and uptime of the equipment. The advantages of using the methods of quantitative thermography, analysis of the quality of electrical energy and control of the hardness of cable insulation have been experimentally established. With the help of an analyzer of electric energy quality, measurements of the quantitative indicators of the operation of the electric motor have been carried out; the thermal imager has been used to assess the thermal state of contact connections and cable routes. The use of new diagnostic methods is of particular relevance in the course of continuous long-term operation of electric transport in the Far North.