The analysis of the influence of variable roadbed stiffness and support of railway sleeper on its work

The main purpose of a railway sleeper is to sustain rail forces from the wheels of rolling stock and transfer them to the ballast bed. Moreover, sleepers maintain a mutual distance between the rails - railway track width. During the analysis of railway sleeper work the following basic parameters are considered: • strength and durability, • sleeper width (load on ballast transmission), • sleeper length (various deflection - sleeper ends, under-rail zone; sleeper center), • possible narrowing in the sleeper midpart (concrete) that reduces support damage in the midpart, • variable sleeper stiffness per length, • sleeper roughness (friction arising between the ballast and the sleeper), • variable value of subgrade coefficient C [MPa/m] or elasticity modulus U [MPa], • nonsymmetrical load transferred from the rail to the sleeper. In the paper a problem of railway sleeper work at variable coefficients of subgrade flexibility is considered. The analysis includes static quantities, particularly the quantity and distribution of the bending moment of the railway sleeper.