• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1526-1532
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• 2014

The Electronic Interlocking unit in railway signalling system is safety-related facilities to determine route and speed for train running. In particular, the SSI(Solid State Interlocking) is Electronic Interlocking unit for high-speed railway, and it performs safety-critical function by MPM(Micro-Processor Module). Meanwhile, MPM is composed of the PES(Programmable Electronic System)-based system, and the PES-based system in railway safety-related facilities should be implemented by complying with the safety requirements defined in IEC 62425 and IEC 61508. In this paper, we performed modeling of failure rate and reliability for MPM implemented by fault tolerance methods and analyzed functional safety for MPM. Moreover, we determined SIL(Safety Integrity Level) for MPM according to the safety requirements defined in IEC 61508 based on an analyzed functional safety.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.661-666
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• 2006

Interlocking signalling system plays key role as core system to manage railway operation. The core role of railway operation is to control routing, displaying signal and regulation for train. Interlocking system relate tightly to railway accident because collision and derailment is sometime taken place wrong route setting and signal displaying. Safety activity for interlocking system is inevitable to avoid the accident over its life cycle. The safety activity includes hazard identification and analysis, safety requirement allocation, safety plan, safety activity and ao on. The safety activity need a broad wide range work. In this paper, we concentrate on hazard identification for generic interlocking system and programmable electronic interlocking system and compare between two results. The hazards will be used for safety activity.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.667-673
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• 2006

Programmable electronic interlocking system plays key role in railway operation and is closely related to railway accidents, in which the programmable electronic controller of interlocking system may become sources. Redundant digital controllers are adopted as the interlocking controllers to prevent the accidents from the controllers being out of order. The redundant digital controllers being fault tolerant are realized through dual or triplex controllers. In this paper, we calculated safety and availability of the redundant digital controllers using Markov models, demonstrated key part to determine the availability ana the safety.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.55-63
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• 2017

Railway interlocking systems which are safety-critical systems are rapidly changed from relay-based systems to computer-based systems which have high flexible. Computer-based interlocking systems (CBI) are consisted of hardware and software in which system safeties arise one of important problems. The interlocking software of the CBI influences directly to the system safeties. "z" notation is one of formal methods have been used for system software specification to secure system safety. In this paper, the specification of interlocking logics for CBI systems is realized using "z" notation and verifies it with Z/EVES.