• Journal of the Korean Society for Railway
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• v.1 no.1 s.1
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• pp.10-19
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• 1998

Described in this paper is the software to design of a railway interlocking table, which describes the functional specifications of an interlocking device. Interlocking tables has been designed mainly based on personal expertise among signal engineers. However, this expertise needs to be analyzed with technical uniformity and integrated in an organized system. The proposed software is amount to the signal engineer's expertise, yet a generalization of interlocking reasoning. The algorithm is based on the train route setting principle, and is applicable in solving practical problems by computers. The software was evaluated through man-made and machine-made interlocking tables are compared. The evaluation results proves the software to be effective for computer control of the signaling system as interlocking system with a much improved 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.

• 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 P
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• v.53 no.2
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• pp.70-76
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• 2004

The purpose of interlocking system in railway is to prevent the route for a train being set up and its protecting signal cleared if there were already another, conflicting route set up and the protecting signal for that route cleared. Recently, conventional relays circuitry in industrial field is replaced to computer-based control systems according to the advance of computer and communication technology. Therefore, interlocking systems in railway field are rapidly changing from existing relay-based interlocking system to computer-based electronic ones that executes the vital interlocking logic to assure the safety train routes at trackside signaling equipment room using electronic circuits. So it is very important to verify the performance of developed electronic interlocking system by plentiful laboratory testing before actually application in the railway system. However the laboratory testing in the present state of railway signaling is preformed individually by manual, so very much test time and cost are required. To solve these problems, we are developed the simulator for automatic interlocking inspection in this research. This simulator is able to operate on general personal computer and has following beneficial functions : automatic test sheet generation for inspection, automatic inspection execution and et al. The experiments are executed to test the feasibility of the developed simulator the experimental results have good agreements with the anticipated ones.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.11
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• pp.1457-1463
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• 1999

This paper develops an real-time expert system for the electronic interlocking system. it obtains the higher safety by determining the railway interlocking strategy in order to prevent trains from colliding, and derailing in the viewpoint of veteran expert, considering the situation of station in real-time. The expert system determines the real-time interlocking strategy by confirming the interlocking relationships among signal facilities based on the interlocking knowledge base from input information such as signal, points, and it is implemented as the rule-based system in order to represented accurately and effectively the interlocking relationships. Especially in case of emergency the function which determines the rational route coordinating with IIKBAG on the workstation is designed in order to minimize the spreading effect. It is implemented in C computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the build and interface of the station structure database. And, the validity of the built expert system is proved by simulating the diversity cases which may occur in the real system for the typical station model.

• Journal of the Korean Society for Railway
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• v.5 no.2
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• pp.104-111
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• 2002

The purpose of interlocking system was to prevent the route for a train being set up and its protecting signal cleared if there was already another, conflicting route set up and the protecting signal for that route cleared. This paper proposed Interlocking Inspection System(IIS) consisting of interlocking simulator and field simulator to operate interlocking test of computer based Electronic Interlocking System(EIS) in this paper. Interlocking simulator consists of Design Edit System(DES), Logical Database Management Tool(LDMT) and real-time confirming system, field simulator is a equipment to simulate a control object of EIS and constitutes configuration operated in 19 inch standard rack. As a result of test to prove capacity of this IIS, the efficiency was shown as excellent. Therefore by using inspection system, we obtain every advantages. It has the functions for test data generation and automatic test execution based on personal computer. Time and cost for test work can be reduced more efficiently by using this developed inspection system

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.831-839
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• 2009

An interlocking equipment of railway signalling systems is manufactured with electrical devices and electrical interlocking equipment has been substituted for existing interlock equipment(relay sequential logic type). But interlock conditions are still generated from rail diagram and used to make Interlock Table manually. In order to make EIS(Electrical Interlock System) operate, we should write interlock data which is made from interlock table. But, as the station is larger and more complicated, handwork may becomes a very tediou work and makes more mistakes. Therefore the development of CAD system for Interlocking System is very significant, if CAD can reduce the mistakes from handwork and help the configuring the interlocking system. In this paper, we first arrange some rules which can be used to extract route information automatically from rail diagram and interlocking rules. And then we propose "Search-And-Rollback" algorithm to extract route information and individual interlocking rules. The proposed algorithm is implemented and tested through the signal design process of the Hyundai-Steel private railway to carry melted pig iron from the blast furnace to the steel-making workshop. some cases. It shows that CAD for Interlocking system is very helpful in time saving aspect and system reliability.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.427-435
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• 1998

In this paper will be presented an algorithm for designing of a railway interlocking table which is a document describing the functional specification of the interlocking device. The ability to produce an interlocking table has been handed down in the signalling engineers society. And the signalling engineer makes the most of his expertise to produce an interlocking table. But, the expertise has not yet been organized into technical system, the core of the expertise is a hard nut to crack. Therefore, we analyze into signal engineering expertise, and propose a generalization of interlocking notion. Also, an algorithm is drawn up based on a train route setting principle to solve practical and general problems by computer And the performance of the algorithm is evaluated for test program based on AutoCAD technology. The evaluation result shows that it can be utilized as the effective algorithm for computer control of the signalling system as interlocking device, that it improved in safety

• 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.

• International Journal of Railway
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• v.2 no.3
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• pp.99-106
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• 2009

Checks and tests before putting safety facilities into service as well as the results of these tests are essential, time consuming and may show great variations between each other. Economic constraints and the increasing complexity associated with the development of computerized tools tend to limit the capacity of the classic approval process (manual or automatic). A reduction of the validation cover rate could result in practice. This is not compatible with the French national plan to renew the interlocking systems of the national network. The method and the tool presented in this paper makes it possible to formally validate new computerized systems or evolutions of existing French interlocking systems with real-time functional interpreted Petri nets. The aim of our project is to provide SNCF with a method for the formal validation of French interlocking systems. A formal proof method by assertion, which is applicable to industrial automation equipment such as interlocking systems, and which covers equally the specification and its real software implementation, is presented in this paper. With the proposed method we completely verify that the system follows all safety properties at all times and does not show superfluous conditions: it replaces all the indoor checks (not the outdoor checks). The advantages expected are a significant reduction of testing time and of the related costs, an increase of the test coverage rate, an answer to the new demand of railway infrastructure maintenance engineering to modify and validate computerized interlocking systems. Formal methods mastery by infrastructure engineers are surely a key to prove that more safety is not necessarily more expensive.