The article presents, against the background of technical diagnostics development, diagnosing and monitoring methods for equipment and process engineering lines, reliable and offered at present by the Company Zaklady Remontowe Energetyki Warszawa S.A. (ZREW). These, usually very responsible and sophisticated, technical systems are driven by electric motors. Many years of experience justifies the selection of, indicated in the paper, physical quantitative, the measurement of which allows efficient elaboration of a diagnosis. First of all, an important role of the vibration signal in examination of this type of objects was singled out. The ZREW uses high class equipment and specialised diagnostic programming. The above-mentioned means make possible, after a logistic reconnaissance of objects, elaboration of proper for them, diagnostic, monitoring and supervising procedures, and of methods for measurement signals processing. The article points out the significance of organisation of computer databases and of ergonomic ways of communication with services performing measurements and with their principals. An important conclusion is the proof of how important is the firm's quality system for correct performance of diagnostic tests and for satisfactory cooperation with the company's customers. In the ZREW it is organised according to the ISO 9001:2000 norm provisions. Works, performed by the diagnostic staff of the ZREW, bring as the result, every time, lowering of operating costs of equipment with simultaneous increase of the equipment's availability and reliability. They influence directly high economic effectiveness of the company, which ordered the diagnostic tests.