**Company Description** **Work with Us. Change the World.** At AECOM, we're delivering a better world. Whether improving your commute, keeping the lights on, providing access to clean water, or transforming skylines, our work helps people and communities thrive. We are the world's trusted infrastructure consulting firm, partnering with clients to solve the world’s most complex challenges and build legacies for future generations. There has never been a better time to be at AECOM. With accelerating infrastructure investment worldwide, our services are in great demand. We invite you to bring your bold ideas and big dreams and become part of a global team of over 50,000 planners, designers, engineers, scientists, digital innovators, program and construction managers and other professionals delivering projects that create a positive and tangible impact around the world. We're one global team driven by our common purpose to deliver a better world. Join us. AECOM’s **Enterprise Capabilities** team is looking for a **Tunnel Ventilation Systems – Principal Mechanical Engineer / CFD simulation** to join our team in Madrid. **About Enterprise Capabilities** Fundamental to our _Think and Act Globally_ strategy and digital adoption, Enterprise Capabilities (EC) is AECOM’s primary vehicle for workshare. Operating across geographic boundaries and time-zones, EC partners with regional and Global Business Line project teams to provide technical expertise, accelerate delivery and keep AECOM competitive in the industry. With a team of over 3000 technical professionals located across nine countries and remote technical anchors, EC teams are trusted to deliver high-quality, specialist services that help to fill capability gaps, resourcing needs and technical constraints on projects of all scopes and sizes. **Start here. Grow here.** **Job Description** We are seeking a **Principal Mechanical Engineer with extensive experience in Tunnel Ventilation Systems (TVS) and Computational Fluid Dynamics (CFD) / Subway Environment Simulation (SES) modelling** for Metro, Rail, and Road tunnel projects. The role includes technical leadership, ventilation system design, simulation oversight, and client-facing coordination. You will lead engineering deliverables to ensure ventilation and smoke control systems meet operational, safety, and regulatory requirements. **Here is what you will do:** + Lead the design, verification, and performance assessment of Tunnel Ventilation Systems (TVS) for Rail, Road, and Metro tunnels. + Serve as a primary technical representative to clients (both internal and external), participating in workshops, reviews, and responding to technical queries. + Prepare and/or review engineering calculations, system layouts, mechanical design drawings, equipment sizing and technical specifications. + Ensure all designs comply with Employer Requirements, project specifications, and applicable standards, especially when coordinating with FLS (Fire & Life Safety) and RAMS teams. + Lead the development of simulation models on SES (Subway environment simulation), IDA Tunnel, FDS (Fire Dynamics Simulator) or any other equivalent software for defining the air flow requirement of TVS fans and also for fire simulation for various scenarios. + Lead the development of 3D CFD simulation on Pyrosim or any other equivalent software for Smoke Management system. + Coordinate TVS design with other disciplines, especially SMEP (Structural, Mechanical, Electrical & Plumbing), Architecture, Systems and Civil, to correctly develop models that accurately reflect the tunnel networks, station(s) and facilities. + Collaborate and. + Lead space proofing and equipment access/maintenance planning for TVS components. + Prepare and validate Modes of Operation (MoO) tables for system control and integration with SCADA (Supervisory Control and Data Acquisition) / tunnel control systems. **Qualifications** **Here’s what we’re looking for:** + A minimum of 8 to 10 years of experience in Metro, MRT/LRT, Rail/Road tunnel ventilation design simulation + Proficiency in SES (Subway environment simulation), IDA Tunnel, FDS (Fire Dynamics Simulator) or any other equivalent software + Willingness to take on the challenge of leading and developing a new multidisciplinary engineering team, fostering collaboration, knowledge sharing, and high-quality technical delivery. + Familiarity with BIM workflows and design coordination platforms (ACC, SharePoint, ProjectWise). + Excellent analytical and problem-solving skills + Ability to perform complex calculations and conduct engineering tests + Experience in gathering and correlating engineering data + Strong communication and interpersonal skills + Capability to work independently and manage multiple projects efficiently. + Capability to develop and grow teams. + Familiarity with relevant industry codes and standards + Demonstrated ability to innovate and think creatively in engineering solutions + Excellent organizational skills and attention to detail + Willingness to learn and adapt to new technologies and methodologies **Preferred Qualification:** + Bachelor’s degree in Mechanical Engineering, or related discipline, complemented by specialized training in tunnel ventilation, fire safety engineering, or CFD simulation. **Additional Information** **At AECOM, you will have freedom to grow in a world of opportunity** _At AECOM, our Freedom to Grow philosophy supports flexibility and balance to help our people thrive._ \#LI-GA1 **About AECOM** AECOM is proud to offer comprehensive benefits to meet the diverse needs of our employees. Depending on your employment status, AECOM benefits may include medical, dental, vision, life, AD&D, disability benefits, paid time off, leaves of absences, voluntary benefits, perks, flexible work options, well-being resources, employee assistance program, business travel insurance, service recognition awards, retirement savings plan, and employee stock purchase plan. AECOM is the global infrastructure leader, committed to delivering a better world. As a trusted professional services firm powered by deep technical abilities, we solve our clients’ complex challenges in water, environment, energy, transportation and buildings. Our teams partner with public- and private-sector clients to create innovative, sustainable and resilient solutions throughout the project lifecycle – from advisory, planning, design and engineering to program and construction management. AECOM is a Fortune 500 firm that had revenue of $16.1 billion in fiscal year 2024. Learn more at aecom.com. **What makes AECOM a great place to work** You will be part of a global team that champions your growth and career ambitions. Work on groundbreaking projects - both in your local community and on a global scale - that are transforming our industry and shaping the future. With cutting-edge technology and a network of experts, you’ll have the resources to make a real impact. Our award-winning training and development programs are designed to expand your technical expertise and leadership skills, helping you build the career you’ve always envisioned. Here, you’ll find a welcoming workplace built on respect, collaboration and community - where you have the freedom to grow in a world of opportunity. As an Equal Opportunity Employer, we believe in your potential and are here to help you achieve it. All your information will be kept confidential according to EEO guidelines. **ReqID:** J10139543 **Business Line:** Transportation **Business Group:** DCS **Strategic Business Unit:** Enterprise Capabilities **Career Area:** Engineering **Work Location Model:** Hybrid