This document is the final report for Phase I of a two-phase research project, “User-Centered Design for Railroad Automation (UCD-Rail),” to develop and demonstrate an improved interface between human operators and advanced automation in rail systems. Applying user-centered design methodology, Phase I offers a new rail systems user interface concept called the Automation Awareness Assistant (A3). A3 will improve human operator situation awareness of automated rail functionality and suggest what actions to take if a possible system failure is detected, especially under conditions of high operator workload. A3 will be designed for locomotive cabs, but the A3 user interface concept can be applied and extended to other related rail and transportation systems.