In January 2025, TRA Safety Engineering supported United Airlines with safety certification of the modification of ITT train control cabinets at the Terminal B station of the Subway automated people mover system at Geroge Bush Intercontinental Airport (IAH). Relocation of the ITT cabinets was a necessary step in the IAH Terminal B Transformation project, which is intended to boost passenger experience and capacity at IAH. The ITT cabinets control critical operations such as train separation and station berthing. Modifications to the cabinets included relocation and replacement of power and data cabling, followed by a rigorous battery of verification tests. TRA Safety Engineering provided a safety certification plan, verification test review and approval, onsite technical support, witnessing of test and commissioning, and a final safety certification report. The successful completion of the plan supported United Airlines efforts in the Terminal B Transformation project, and was testimony to the collaborative effort between TRA, Airports of Houston, United Airlines, and their contractors.

Safety certification was crucial for this project because it integrated hazard identification and management, component level testing, and system performance testing. Using subject matter expertise in train control, TRA Safety Engineering worked with the client to identify all hazards presented by the control cabinet modifications and the mitigations for each hazards. This process followed industry-wide accepted hazard management practices as defined in MIL-STD-882E for systems safety. Given the direct relationships between systems testing and hazard mitigations, each hazard as successfully closed and revenue service was resumed with evidence of a rigorous safety management process.