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Fatigue damage of rail steel is an important issue affecting economic and human safety. In this paper, the effect of different quenching rates on the fatigue crack growth of hypereutectoid rail is analyzed. The material parameters C and m of the Paris formula are measured. The results show that an increase in cooling rate of rail decreases the value Paris law parameter C, increases the value m and decreases fatigue crack growth rate. This can be attributed to the decreased in the lamellar spacing and cluster diameter of the pearlite with an increase in cooling rate. More specifically, the smaller lamellar spacing and the cluster diameter make the crack pass easily through the cluster boundary of pearlite, which increases the number of zigzag crack growth paths and branching cracks that can help restrain fatigue crack growth. The fatigue fracture characteristic of hypereutectoid rail is that with an increase in cooling rate, the fatigue striation spacing and river pattern of the fracture surface become smaller, the crack growth path tends to zigzag, the tearing edges become deeper and the surface is relatively rougher. [ABSTRACT FROM AUTHOR]