A double-hierarchical interval-type-2 fuzzy sliding mode controller was proposed to address poor tracking accuracy and low robustness of high-speed trains under complex operating environments. In the upper-layer design, an adaptive switching gain based on an interval-type-2 fuzzy logic system was developed, whereby precise estimation of external disturbances was achieved through compensating for the uncertainties of membership functions. For the lower-layer control, a hyperbolic-exponential composite power reaching law was employed, and a continuous smooth function was constructed to replace the traditional sign function. Consequently, the discontinuous switching of the control input was successfully eliminated while the fast convergence characteristics of the power reaching law were effectively retained. A simulation was conducted based on actual data of the CRH380A high-speed train running on the Suzhou North–Shanghai Hongqiao section. The velocity and displacement tracking errors of the proposed controller were 0.000 005 m/s and 0.002 82 m, respectively, achieving high-precision tracking of the target trajectory throughout the operation.