Testing Railway Interlockings with
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Transcript of Testing Railway Interlockings with
Testing Railway Interlockings with
N. Ioustinova, J. van de Pol, N. Goga
Centrum voor Wiskunde en Informatica
Amsterdam, The Netherlands
TT-Medal Review
Berlin, Germany
September 28, 2005
This work is done in cooperation with ProRail
TT-Medal Review, September 2005
GoalProvide a framework for testing railway interlockings
with TTCN-3
INTERLOCKING LAYER(guarantees safety of railway control system)
INFRASTRUCTURE(railway tracks, signals, level crossings, points etc.)
LOGISTIC LAYER(human-experts interface) Railway Control
System
Apply the framework for testing interlocking software for Hoorn-
Kersenboogerd station
TT-Medal Review, September 2005
1 3 5 7 9 11
8 10
2 4 6
Development of Test Cases
test suite for interlockingof Hoorn-Kersenboogerd
standards
on railway safety
TT-Medal Review, September 2005
Development of Test System
Test Management (TM)
TTCN-3 executable (TE)
TCI
TRI
Platform Adapter System Adapter
Time Manager
IdlenessHandler
IdlenessHandler
IdlenessHandler
IdlenessHandlerTCMTC
TTCN-3 Test System forrailway
Special feature: time control simulated time
interlockingsSUT
Interlocking Simulator
Interlocking Program
Simulated time solution is based on Dijkstra’s distributed termination detection algorithm
TT-Medal Review, September 2005
66C 66B 66A 74B
60
68
Expectedtrace
Observedtrace
66C 66B 66A 74B
60
68
FAIL
Initial situation: train on 66C
Setting the initial situation costs 21 cycles.
Failure is detected in 1 cycle.
Test Execution: Normal Train Departure
Final situation: train at 66B and 68 remains yellow
TT-Medal Review, September 2005
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
TT-Medal Review, September 2005
TTCN-3 for the Railway DomainAdvantages 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
TT-Medal Review, September 2005
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
Conclusions