Ozgur Turay Kaymakci

Signaling System Solution for Urban Railways: Esenler Railway Depot

Abstract Among other transportation alternatives, rail transportation is of great importance in urban transportation. Especially in crowded cities such as Istanbul where over thirteen million people live in, the use of urban rail transportation is inevitable due to traffic jam at peak hours. In this study, information about the first urban light rail transit M1 railway line is given and the signaling solution proposed for Esenler railway depot which is established in M1 railway line is explained.

Reliability assessment of fire safety systems in railway industry: a case study

Within the framework of railroad transportation systems, there are currently system rooms where critical systems such as signalization are available. For the system to achieve an uninterrupted mode of operation, it is crucial to mitigate risks or hazards against the rooms and to ensure an acceptable level of safety. This study handles the protection of a system room, owned by Istanbul Ulaşım A.Ş. Edirnekapı branch, against an incident of fire as a safety-related system practice. Within this scope, the fire safety system has been handled as a safety-related system identified in IEC 61508. The safety integrity level required by the safety lifecycle for the relevant system has also been identified and safety functions that are required to be implemented have been put forth. Taking IEC 61508 as a reference for the functions, the required analyses have been performed through fault tree analysis. It has also been guaranteed that the relevant functions have met the required safety levels.

Effects of varying diagnostic coverage on functional safety

Diagnostics is one of the significant parameters of functional safety which concerns itself with revealing dangerous incidents that might impede the operation of safety systems. Diagnostic coverage factor (DC) is defined as a metric for diagnostics in that DC is one of the most important design parameters to measure the effectiveness of safety protection systems. This study addresses how diagnostics impacts proof test interval (TI) when the system is halted completely; a thorough maintenance and changes in parts are performed. Besides this, the relationship between average probability of failure on demand (PFDavg), DC, TI and mean time to failure (MTTF) are presented for 1oo2 and 1oo2D system architectures.

Specification and Formal Verification of Safety Properties in Point Automation System by Using Timed-Arc Petri Nets

Abstract In this study, control structure related to the safety of the point automation system, which has a critical significance on tram lines, was designed through Timed-Arc Petri Nets by taking CENELEC 50128 standard as reference. CENELEC 50128 strongly recommends the utilization of Timed-Arc Petri Nets during system modeling (Table A.17) and the utilization of formal proof methods during the verification and test phases of command and control structure developed (Table A.5). The verification was performed through CTL (Computational Tree Logic), which is one of the formal proof methods. Timed-Arc Petri Nets model has been used for the first time in this area through this study. Within this context, the structure was developed by taking the point automation system at the Bastabya Station on T4 Topkapi-Habibler line, operated by Istanbul Ulasim as the reference. Moreover, safety requirements for the automation of the points were identified and denoted mathematically while their safety functions were designed.

The Relationship between Diagnostic Coverage and Proof Test Interval for 1oo2 and 1oo2D Architectures

Abstract In order to measure the effectiveness of safety protection systems there are several design parameters. Diagnostic coverage factor is one of the most important parameter which influences all architectures. In this short paper the relationship between PFD avg , DC and T I are presented. 1oo2 and 1oo2D architectures are considered as examples.