Around the world, SYSTRA’s specialists plan, design, integrate, test, commission, project manage and deliver mass transit and mobility solutions that are relied on by more than 50 million people every day.

For more than 60 years, the Group has been committed to helping cities and regions contribute to their development by creating, improving and modernising their transport infrastructure with sustainability, accessibility and innovation at the heart of our designs. With over 10,300 colleagues globally and around 1000 in the UK & Ireland we are growing significantly and seeking out the very best talent to join the SYSTRA signature team and be part of leading the way in infrastructure design.

The Principal Consultant (Software Development) will design, build, and maintain high-performance software systems while acting as a technical reference point for less experienced team members.  You will work closely with the Technical Lead and cross-functional teams to deliver features that are reliable, testable, and maintainable — contributing to architecture decisions and championing engineering best practices across the codebase

• Design, develop, and maintain SYSTRA's proprietary microsimulation software Paramics Discovery using C++, C#, and Python across the full software development lifecycle.
• Write clean, efficient, well-documented code with a strong emphasis on testability and performance.
• Participate in architectural and design discussions, contributing well-reasoned proposals and technical trade-off analysis.
• Review code from peers and provide constructive, detailed feedback that raises the quality bar for the whole team.
• Collaborate with DevOps colleagues to optimise CI/CD pipelines and ensure smooth, repeatable deployments.
• Interact with SQL databases - writing, reviewing, and optimising queries and stored procedures.
• Mentor less experienced developers, supporting their technical growth and embedding best practices.
• Contribute to test strategies including unit, integration, and performance testing.
• Participate in agile ceremonies: sprint planning, stand-ups, retrospectives, and technical refinements.
• Demonstrate behaviours aligned with SYSTRA’s behavioural framework by actively fostering a culture of excellence, collaboration, respect, and empowerment, contributing to an environment where all colleagues can thrive, achieve and grow together

Essential Skills / Knowledge / Experience

• Proficient in C++. Strong command of modern C++ (C++14/17/20), including memory management, templates, STL, and performance optimisation.
• Proficient in C#: Solid experience with the .NET ecosystem, including .NET Core / .NET 6+, async programming, and OOP design patterns.
• Proficient in Python: scripting, automation, data processing, or back-end service development.
• Software Engineering Fundamentals: Deep understanding of algorithms, data structures, design patterns, and SOLID principles.
• Debugging & Testing: Experience with unit testing frameworks (e.g. Google Test, NUnit, pytest) and profiling / debugging complex systems.
• Version Control: Comfortable with Git-based workflows including branching strategies, pull requests, and code review processes.
• Communication: Able to explain technical decisions clearly to both technical and non-technical stakeholders.
• configuration and deployment of solutions

Desirable Skills / Knowledge / Experience

• SQL: Experience writing and optimising SQL queries, stored procedures, and working with large relational datasets.
• DevOps Practices: Familiarity with CI/CD pipelines (e.g. Jenkins, GitLab CI, Azure DevOps), containerisation (Docker), and infrastructure as code.
• Cloud Platforms: Exposure to AWS, Azure, or GCP - particularly compute, storage, and networking services.
• Regulated Environments: Experience working in high-integrity, or regulated industries (e.g. defence, finance, transport, aerospace) is advantageous.
• Cross-language Systems: Experience integrating components written in multiple languages (e.g. C++ core engine exposed via Python bindings).