This study aims to establish the fundamental basis for the design of materials used in high-speed trains, by using a lab-scale dynamometer to evaluate the characteristic behavior of metallic sintered friction materials in relation to the shape of graphite. The test results clearly demonstrate that when flake graphite and granular graphite are added equivalently, the average coefficient of friction is much lower, and it is less influenced by speed variation; moreover, friction wear is observed to be insignificantly low. Adding flake graphite increases the coefficient of friction, which leads to higher friction wear. In addition, the roughness of the disc surface was equivalent regardless of the shape of the graphite.