The application of supercapacitor energy storage systems (SCESS) in urban rail transit facilitates the recovery and reuse of regenerative braking energy, thereby reducing traction energy consumption and supporting the transition toward low-carbon urban transit systems. Based on an analysis of the structural of urban rail transit networks, this paper proposes an energy management strategy (EMS) founded on dynamic programming, which enables effective matching between the SCESS and traction load demands. To validate the effectiveness and advanced performance of the proposed EMS, a 1.5 MW SCESS prototype was developed and deployed on an operational metro line in China for field testing. Experimental results demonstrate that, compared to conventional fixed-threshold strategy, the proposed approach improves the average energy saving rate by 5.49%. These findings confirm the strategy’s superior energy-saving performance and technological advancement, highlighting its practical value for real-world applications in sustainable urban rail systems.