With the development of railway transport, the train speed, the traffic intensity, and the axle load all permanently increase in magnitude. This increase adversely affects the rail operation. The quantity of rail defects and, especially, the rate of rail-head surface wear both show an increase. Such service conditions require an enhanced mechanical strength of rails, their enhanced resistance to wear, and prolonged service life. In the present study, we analyze the operation performance of modern differentially quenched rails in comparison with domestic volume-quenched rails and Nippon Steel rails (Japan). For evaluating the wear resistance of rails, in the present study we carried out measurements of their side wear at curves of small radius. As a result of the study, it was found that the resistance to wear of differentially quenched DT350 rails 1.5–1.7 times exceeded the resistance of volume-quenched T1 rails. The general-purpose DT350 rails and the advanced DT370IK rails with enhanced wear resistance and enhanced contact endurance exhibited roughly identical wear rates and therefore offered equally long service periods. The Nippon Steel rails have displayed a greater resistance to wear. The side wear of those rails was found to be 1.6 times smaller than that of DT rails, and it met the normative value for surveyed curves of small radius.