Specialist Software Development - Critical Systems SME
Job Summary
This opportunity plays a critical role in CN's Core Modernization program, which is focused on replacing aging Mainframe-based platforms that support mission-critical railway operations including train operations, yard management, and safety-related systems.
The Specialist Software Development - Critical Systems SME is a senior technical contributor who brings deep knowledge of legacy systems while actively supporting CN's transition to modern architectures. The role balances hands-on development and support of existing Mainframe applications with strategic modernization activities executed in collaboration with architecture teams and system integration partners.
This position is ideal for employees with strong legacy expertise who want to contribute their institutional knowledge to a multi-year transformation initiative while ensuring operational stability, regulatory compliance, and safety.
Key Responsibilities
- Provide subject matter expertise for critical legacy Mainframe applications supporting railway operations.
- Design, develop, and implement enhancements to existing Mainframe systems to support regulatory requirements, safety initiatives, and business-driven enhancements.
- Serve as an escalation point for Application Managed Service (AMS) teams by analyzing complex incidents, defects, and performance issues.
- Participate in As-Is and To-Be workshops to document and explain legacy system behavior, business rules, integrations, and data flows.
- Conduct or validate reverse engineering activities to uncover undocumented logic, dependencies, and constraints within legacy codebases.
- Collaborate closely with Architecture, CAST analysis teams, and system integrators to validate modernization assumptions, modularization approaches, and migration readiness.
- Attend solution and design workshops to ensure proposed solutions fully and accurately reflect legacy capabilities and operational requirements.
- Review and validate functional and technical specifications for both legacy enhancements and modernization deliverables.
- Contribute to Agile sprint planning by identifying cross-system dependencies, technical risks, and story complexity.
- Provide input into test strategy, test scenario creation, mock data, and conversion activities.
- Execute and support unit testing, integration testing, regression testing, and performance testing.
- Support business users during User Acceptance Testing (UAT) and participate in sprint demos and retrospectives.
- Participate in deployment and Hypercare activities by supporting defect triage, root-cause analysis, and system stabilization.
Required Skills & Experience
- Strong functional analysis and functional design experience in complex enterprise or legacy environments.
- Solid hands-on development experience using Java and C/C++.
- Proven experience working in Mainframe environments including COBOL and/or Natural/Adabas (asset).
- Strong understanding of batch processing concepts including JCL, VSAM, Syncsort, and enterprise job schedulers.
- Experience with IBM Mainframe platforms (e.g., OS/MVS) and supporting tooling.
- Strong SQL skills with DB2 including analysis and troubleshooting using tools such as Data Studio.
- Experience working with MQ-based messaging and transactions.
- Familiarity with integration technologies such as EDI and webMethods.
- Working knowledge of modern technology stacks such as Microservices, Data Hubs, and event-driven platforms (Kafka).
What We're Looking For
- A candidate with railroad knowledge and willing to develop deep knowledge of CN legacy systems and a strong understanding of railway operations
- A collaborative mindset with the ability to communicate technical concepts clearly to both technical and non-technical stakeholders.
- Strong analytical, troubleshooting, and documentation skills.
- Comfort working in Agile delivery environments and large transformation programs.
- A commitment to system reliability, safety, and operational excellence.
