We are seeking a high-caliber Senior zTPF Systems Engineer to join a mission-critical team in Washington, D.C., supporting one of the nation's most vital transportation networks. This role is designed for a technical expert who bridges the gap between high-performance legacy mainframe systems and modern digital architecture. You will be responsible for developing and optimizing high-volume reservations applications, leveraging a deep mastery of zTPF Assembler and C++ to ensure seamless integration with modern Web Services and API frameworks. This is a unique opportunity to apply sophisticated analytical skills to a complex SOA environment, directly impacting the travel experience for millions of passengers.