This study proposes new approaches for the dissipative analysis issue of high-speed train systems. First, an improved boundary circulatory functional approach is introduced for constructing a weak Lyapunov-Krasovskii functional, which can fully excavate some intrinsic relationships between sampling interval and time delay. Based on the looped-functional tactics and recombinant technology, the constraint conditions are further relaxed for obtaining new theoretical results. Second, by using resultful integral inequalities and correlation analysis approaches, several relaxed criteria are established with respect to the asymptotical stable of the considered sampled-data systems. Third, a new reliable memory sampling controller is designed under the desired dissipative performance. Finally, numerical experiments on high-speed trains on the Shinkansen in Japan illustrate the importance of theoretical results.