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Develop a framework for testing railway interlockings, apply it to Hoorn-Kersenboogerd station, and ensure railway safety standards with a TTCN-3 Rail Control System. Achieve automation, standardization, and reliability in the testing process.
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Testing Railway Interlockings with • TT-Medal Review • Berlin, Germany • September 28, 2005 N. Ioustinova, J. van de Pol, N. Goga Centrum voor Wiskunde en Informatica Amsterdam, The Netherlands This work is done in cooperation with ProRail
Goal Provide a framework for testing railway interlockings with TTCN-3 Railway Control System Apply the framework for testing interlocking software for Hoorn-Kersenboogerd station
Development of Test Cases standards test suite for interlocking on railway safety of Hoorn-Kersenboogerd 8 10 1 3 5 7 9 11 4 2 6
Development of Test System SUT TTCN-3 Test System for railway interlockings Interlocking Simulator Interlocking Program Special feature: time control simulated time Simulated time solution is based on Dijkstra’s distributed termination detection algorithm
FAIL Test Execution: Normal Train Departure Final situation: train at 66B and 68 remains yellow Initial situation: train on 66C Expected trace 66C 66B 66A 74B Setting the initial situation costs 21 cycles. Failure is detected in 1 cycle. 68 60 Observed trace 66C 66B 66A 74B 60 68
Market Relevance • In the European railway sector, the current target is to increase the proportion of railway transportation by 100-150% within a short period (www.railway-technology.com) • European integration (www.euro-interlocking.org) requires new standards for specification (UML) and testing (TTCN-3) • TTCN-3 enables to bring together • Vendors • Standardization • Certification • Operators in EU
TTCN-3 for the Railway Domain Advantages • Standardization: a standard language to specify test suites for railway applications • Reusability: one test suite can be used to test software from different vendors • Independency from implementation details of simulators for railway software • Automation of test execution for railway domain Benefits • High-quality test suites →reliable railway control systems • Reduction of costs for testing on the long run
Conclusions • We translated a subset of CENELEC safety requirements into TTCN-3 test cases. • TTCN-3 is suitable to specify test cases for railway control systems • According to ProRail, TTCN-3 is a significant step towards automation and standardization of testing process in the railway domain • TTCN-3 test system is extended by time simulation option • We have covered whole test-process starting from developing test cases, proceeding with implementing the test system and finally executing tests and interpreting results • Using this approach we found violations of general safety requirements