Researchers sought to determine how to improve the confidentiality of information passing through the Positive Train Control network without significantly affecting network performance. Phase 1 of the project reviewed requirements and assessed existing technologies. Phase 2 focused on implementation, migration, and deployment challenges. A recommendation to consider widely available algorithms covered by recognized open standards resulted in a project decision to focus on the National Institute of Standards and Technology Lightweight Encryption Algorithms and the ELLI algorithm covered by ISO/IEC 29192-4. Phase 3 identified technology gaps and areas for further research outside the scope of the project. Phase 4, the focus of this report, pulls together the work from Phases 1-3 to propose solutions to improve confidentiality, including a concept of operations for each solution.