The infrastructure undertakings of a rail transport and underground are interested in application of composite and switch sleepers. It is connected with the fact that insignificant service life of wooden sleepers and their low resistance to defects increase expenses on repairs and the current maintenance of railway track, especially in difficult operational conditions (the increased humidity, hostile environment, high loadings from vehicle units), and composite under-rail supports have considerably bigger operational resource. Results of research of composite sleepers which material is the polymeric matrix from the processed high-density polyethylene as a main component with glass-filled polymer are given. It is shown that the physical and mechanical characteristics, influencing on operational reliability and operability of composite sleepers of the processed high-density polyethylene as a main component with glass-filled polymer, are above than wooden sleepers have. Spheres of rational application of composite sleepers are offered. For example, on sites where laying of ferroconcrete sleepers is inexpedient, first of all, on the soil blister sites and sites with the weak subballast basis, and also when spacing “bushes” with defective wooden sleepers. On the basis of positive results of tests pilot sites with composite sleepers are put in the Moscow and St. Petersburg underground systems, and also recommendations for their pilot laying on a network of the railroads of JSC RZhD are developed.