This chapter focuses on the refinement stage of railway alignment design, introducing advanced methods for detailed optimization within pre-selected corridor bands. We developed an adaptive optimization framework based on Adaptive Dynamic Programming (ADP) to leverage their strengths for efficient and precise railway alignment optimization. It is called bi-objective adaptive dynamic programming approach for the fine-grained optimization of railway alignments (BA-FORA). A multi-objective function tailored to urban railway design was established, incorporating constraints from adjacent buildings to balance construction costs, safety, and operational stability. Real-world case studies were selected to validate the framework’s effectiveness, considering terrain, building distributions, and traffic conditions. Optimization outcomes were assessed, providing insights for future railway design projects.