It is important to consider robustness when design of brake control systems, because there are the model's uncertainties which result from nonlinear characteristics of adhesion forces between wheel and rail, and friction coefficients of brake materials. This paper presents the experimental results about the new wheel-slip prevention control using nonlinear robust control theory. The authors performed experiments for the proposed wheel-slip prevention control to compare it with the conventional control laws. The experimental results proved the comparative effectiveness of the proposed control and showed high brake performances under nonlinear characteristics of brake dynamics.