Summary
Key results
Compliance with railway standards EN 50128 and EN 50129
Full code coverage at the MC/DC level and integration of the test environment with Jenkins CI/CD
Safety and compliance in testing of critical systems
In train control systems, component testing is not an “add-on to quality” – it is a prerequisite for deployment and a key element of the certification process. The software of ATB and EbiCab 600 modules must meet SIL4 safety requirements, and the testing process must ensure repeatability, auditability, and full traceability between requirements and verification results.
The client needed a partner capable of providing long-term, hands-on support in testing successive versions of ATC modules, while maintaining control over the verification scope (including MC/DC, interface testing, and requirements verification) and improving the efficiency of test preparation. A scalable delivery model was also essential – adjusting team size over time depending on workload – without losing quality or system knowledge continuity. As part of the engagement, the Sii team ranged from 2 to 8 testers depending on the phase and workload.
Sii Poland was selected due to its experience in railway projects and its ability to combine test automation with certification requirements.
VectorCAST- and Cmock-based test environment with CI/CD integration
Sii Poland designed and continues to develop a component testing environment for ATB and EbiCab 600 modules, tailored to support iterative system development and maintenance. The tests were designed to meet SIL4 requirements and enable fast validation of changes across software versions. A key element was integrating tests with CI/CD pipelines and automating selected artifacts required in the verification process.
The scope of work included:
- Design and implementation of a test environment based on the VectorCAST platform, fully integrated with CI/CD pipelines (Jenkins) – using QEMU simulation for rapid iterations and a custom Python framework (including integrations with IBM DOORS and automated generation of reporting artifacts)
- Execution of unit and module tests in C, including both white-box and black-box approaches, with MC/DC coverage and full traceability from requirements → tests → results
- Execution of tests in a hybrid model: primarily in simulation (QEMU), followed by Module Tests on development boards and Subsystem Tests on target hardware in the client’s laboratory in Germany
- Implementation of a defect analysis and reporting tool enabling rapid response to issues and root-cause elimination; test results and artifacts were used in external certification (e.g., TÜV/ISA)
- Optimization of regression testing and maintenance processes – including reuse of test packages across subsequent module versions (where possible), reducing qualification time and costs
As a result, the tests became repeatable, fully automated, and aligned with the certification process, significantly accelerating software validation.
Reduced testing time and increased reliability of control systems
The implemented testing approach improved verification repeatability and structured the traceability path, which is critical for SIL4 systems. Integration with Jenkins and the use of QEMU enabled faster iterations at the component level, while the hybrid model (simulation + hardware testing) ensured validation consistency up to execution in the target laboratory environment in Germany.
An important outcome was also the reduction of risk in subsequent releases through the maintenance and reuse of test packages between versions (where applicable), as well as improved preparation of test documentation through integrations with DOORS and Python-based tools. The project delivered by Sii Poland ensured compliance with railway standards, full test coverage, and increased robustness of control software – directly contributing to the safety of transport systems.
“We have been very satisfied with the collaboration we have had with the Component Test Engineers from Sii. They have been instrumental in our work package focused on Component Testing using VectorCast for SIL4 Onboard Signalling Systems, which get deployed on railway vehicles in Germany and the Netherlands. We have consistently appreciated the professional and competent support provided by Sii throughout this project. Based on our positive experience, I highly recommend Sii for similar work packages.” – Tobias Klein, Program Manager, Alstom Signal GmbH