Automatic control of full barrier level crossing systems and safety analysis

The role of railway transport, including conventional and fast railway lines, has become an undeniable role for centuries in the world. The transportation activities of the great trades, the railway operation where the cities and the intercountry journeys are carried out and finally the urban tram and subway lines, state. Rail transportation systems that are rapidly spreading all over the world, including our own country, are progressing in the future to become a more preferred transportation choice with the completion of the life of fossil fuel use. The unpredictable sides of human behavior are at the top of the reasons that make railed transportation systems automatic. The concept of safety is specially defined for the railway, and with the accumulation of knowledge, international standards have been established. Designs based on railway transportation should be compatible with these standards. Level crossings are the intersection of railway and highway traffic in railway transportation. Therefore, they are the most risky and dangerous open spaces in today's railway business and especially in our country. The designs to be made are safe and fully compatible with existing business and can reduce or eliminate all risks. A comprehensive and sufficient safety requirements has been put forward in consideration of all possible factors such as human, environment, railway systems and highway in which the crossing systems are related. Level crossings take many forms depending on whether they are on a public or private road, or for vehicle, horse or pedestrian use. The protection arrangements which are appropriate at level crossings will vary, depending upon the crossing location, for example proximity to road junctions, the level of usage and the nature of railway traffic. System design activities should be carried out within the safety life cycle defined in the standards. The system to be realized does not end up in a single organization. The life cycle of the system is complemented by the internal workings of independent organizations. At the beginning of these independent organizations are the assesor, validation and verification team. These organizations work separately from the design and project management team. Relations to each other are also carried out as referenced in the standard. Identification of the safety needs of the system and identification of the required hazards is at the beginning of the initial processes. System identification is also the process. The system has a critical prescription to fully express all the details together with the environment, people, subsystems and relationships with equipment. The risk xviii analysis and identification activities to be carried out follow the system identification phase and have a close relationship with the consistency of the study. In Chapter 2, general information on level crossing gate types and study and signaling methods are given. Gateway types, gated level crossings, barrier level crossings has a working structure under the control of officials including railway. Obstacle clamping, automatic half barrier, barrier and barrier-supervised local employees, including automatic and signaling gateway that communicates with the system in types are introduced in this section. In Chapter 3, the life cycle phases in which the level crossing gate system design activities are carried out and the activities they are involved in are introduced. The safety structure that the system should have within the safety concept is designated as SIL4. The organizational scheme brought by this level of safety has been expressed. The risk assessment processes and the methods and techniques to be used are outlined in general terms. Section 4 begins with the identification of the hazardous situations and possible sources for the automatic full-barrier level crossing gate system. The FMEA analysis was then used to pre-assess existing risks. Quantitative analysis has been carried out and many of the hazards with the risk mitigation activities to be taken have been drawn to the level of 'negligible' and 'acceptable' risk. For hazardous situation 34, qualitative analysis was applied and a detailed analysis was carried out by FTA. Safety and functional requirements are defined as a result of analysis carried out at the next phase. A core algorithm flow diagram is provided to execute control and manage of the system in these defined lights. The otomat model that provides the transition from the flow diagram to the programmable code has been obtained by a practical method. The state and transition statements are obtained from the flow diagram of the prepared algorithm. In total definition of the system was introduced when the safety analysis work was started. The system definition has been extensively described to include the entire system, subsystem, and environment to which the automatic level crossing system is related. Then all potential hazardous situations from the system's knowledge and experience and their possible root causes have been identified. Possible hazard scenarios have been identified from the sources of the obtained hazards. FMEA analysis has been performed to reduce the risk levels of these hazards and reduce the risk levels of the hazardous situations without qualitative analysis if it is possible to reduce the risk level. Then an analysis based on an FTA was used to investigate the hazard situation requiring detailed analysis. Functional and safety requirements are defined on the basis of risk mitigation activities obtained as a result of risk analysis studies. The flow diagram is designed according to the needs. Thus, the requests in the informal structure are passed into a semi-formal structure. As a control method, a new approach has been used to obtain the flow diagram of the automata (state graph) expression. With the formal control method obtained, a realization method following the system life cycle is introduced. The system has been programmed with any programmable electronic device. The work carried out in our country includes all the details that will ensure the safe handling of the processes of automation of full barriers. The whole process including the design and implementation studies of the system, starting from the risk analysis studies, has been discussed in detail. The autonomous full barriers are used both in urban transportation and in rural areas. The automatic full barriered gate system,which is designed for railway systems with signaling system and without signaling, is easily used. In this thesis study, the safety analysis of the structure related to automatic full barriered bypass system has been made and control of the system is ensured. Further study can be carried out to carry out analyzes of reliability, accessibility and maintainability activities and to identify system safety life cycle activities associated with them. A reference resource for operation and maintenance activities can be established for the automated full-bodied passageway system together with the provision of required requirements. Rail transportation engineering requires a realistic conception of system safety with a systematic approach. Practical experience along with necessary engineering tools and creative activities such as brain storming are integral parts of these studies. In the literature, firstly, studies on the safety analysis of the automatic full barriers and the creation of the control model have been carried out. While establishing a formal control method, an innovative approach has been developed for the flow diagram of the system and the transition to the vending model has been achieved in a simple and practical way. The analysis and design activities carried out in the thesis study were carried out in accordance with the phases stated in the life cycle. Life cycle phases are given in Cenelec standarts (50126,50128,50129) in detail. The study is not just an industrial application, but it also includes a comprehensive analysis for the automatic full-barriers and a simple and practical method of control, including the identification process. The work carried out on the control side involves the creation of a flow diagram suitable for each request and then a simple and rapid design of the state and transition statements of the vending machine model via this flow diagram. In the study carried out within the scope of the thesis, while creating a formal control method, an innovative approach has been developed for the flow chart of the system and the transition to the vending model has been provided in a simple and practical way. The vending machine model is used because of its advantages such as open structure and easy construction. The flow chart is designed first with the purpose of removing the vending machine model. In this thesis study, studies on safety analysis, safety and functional requirements and otomat control (state transition graph) and control model studies have been carried out. Risk level assignment for all identified hazardous conditions has been implemented. Risk mitigation activities for 'intolerable' and 'undesirable' risk levels have been defined following risk level definition. Statement of risk analysis includes FMEA and the FTA is carried out for the identification of the specific hazard with the instrument. Safety requirements and functional requirements are defined for the system. The flow diagram of the control model to meet the specified requirements, the otomat model is provided by obtaining the state and transition statements from the flow diagram in a practical manner. All of these activities carried out within the life cycle will provide a source and guiding work for the safety system design studies.