Emerging Metro Rail Bridge Construction Often Feature Long Welded Rail (LWR), In Which The Track Is Immediately Fixed On The Concrete Superstructure Or Platform. Still, LWR On A Bridge Differs Greatly From LWR On The Ground. Because A Bridge Is Less Stiff Than LWR On The Ground, Deformation Under Different Loads And Thermal Effects Result. The Ultimate Distortions And Stresses In The Bridge And Track Depend Much On The Relationship Between The Track And The Bridge Construction. Known As The Rail Structure Interaction (RSI) Effect, This Interaction Consists In Force Transfer Between The Rail Track And Several Bridge Components: The Superstructure, Pier Cap, Pier, And Pile Cap. Thermal Effects, Braking Or Traction Loads, And Vertical Live Loads From Trains Help To Transfer Force. In This Study, We Investigate The Stiffness And Articulation Optimization Of Metro Rail Structures For RSI Analysis. The Analysis Follows Guidelines From The UIC774-3R Code Of Practice (International Union Of Railways) And RDSO Guidelines For Rail Structure Interaction Studies On Metro Systems Ver 2. We Consider Multi-Span Bridges With Different Span Configurations And Superstructure Types (Such As I-Girders And U Girders). Key Parameters Include The Axial Stresses In The Rail, Relative Displacement Between The Rail And Superstructure, And Support Or Bearing Reactions Transferred To The Bridge Components. The Software Used For Analysis Is Midas Civil. Our Findings Indicate That Considering The Stiffness Of Piles And Piers Can Reduce Axial Stresses In The Rail And Forces At The Bearing Levels.