Concrete railway sleepers have been used for years without an update in production and design, to be compatible with demands for increasing train axle loads and speed. In the current research, concrete railway admixture is modified with consuming (0.5% straight-1.5% hooked), (1.5% straight-0.5% hooked) and (1% straight-1% hooked) steel fibers combinations. Three main mechanical experiments as compressive, flexural and splitting tensile strengths and fresh mortar “flowability” were performed. Results showed that the hybrid of 1% straight and 1% hooked steel fibers shows the optimal performance among other hybrid combinations. This hybrid admixture efficiently improves the compressive, flexural and splitting tensile strengths of the concrete railway sleeper mix design.