Safety management for electromechanical systems of railway vehicles

This paper deals with safety management for electromechanical systems intended for railway applications. The principles and procedures presented in the article are applied in the Lekov Company which is a prominent producer of electric switching and controlling components used in the construction of railway vehicles. Considering the problems of reliability and safety carefully, the Lekov Company puts into practice the integrated safety and reliability program in the process of development, design and production. This article presents a concise characterization of the implemented safety and reliability integrated program which ensures that in the process of development, design and production of new electromechanical equipment, the defined requirements concerning reliability, availability, maintainability and safety will be fulfilled. Due to the limited space for his article, the authors present that part of Lekov's integrated program that pertains primarily to an effective system safety assurance process. The main methods, which are used as parts of the program, are Preliminary Hazard Analysis, Failure Modes, Effects and Criticality Analysis, Fault Tree Analysis and Reliability Block Diagram Analysis. The methods are used in individual steps that logically connect methods each to other. The article describes the procedures of the program and brings a survey of applied methods with characterizations. Particular attention is devoted to problems that are associated with safety management. The implemented reliability and safety program, even if using relatively simple methods, systematically ensures the fulfillment of the customer's requirements for reliability and safety of the system. The logically linked steps taken before the design stage ensure that the engineering design will be carried out effectively, with an emphasis on fulfillment of the given requirements. The design reliability is then checked out by a reliability assessment that precedes the prototype production. This procedure minimizes the possibility of producing a prototype with a structural defect. Prototype reliability tests detect problems which can be corrected and this decreases the probability of occurrence for significant or critical problems in the systems produced in production.