The first example concerns an assem

The first example concerns an assembly of rail, rail pad, and fastener installed on a concrete sleeper. In ballasted track structures with concrete sleepers, static and low frequency elasticity is mainly offered by the ballast underneath the sleepers and by the substructure. Wooden sleepers contribute considerably to static and low frequency track elasticity. Concrete sleepers and slab than tracks hardly do. They are more sensitive to medium to high frequency than wooden sleepers. Internationally standardized tests, such as described in and, concentrate in Sleapers determine the static, low frequency and impact (high frequency) stiffness.