Now as before, concrete sleepers on ballast represent the classical, fundamental version of track systems: in Germany and around the world. In many cases, conventional ballasted track systems fully satisfy the requirements placed. Ballasted tracks offer especially great advantages where refurbishment of existing lines is involved: rail traffic can be partially maintained, even during the construction phase. Total life-cycle costs are increasingly assuming a major role in the planning of new lines. Concrete sleepers can be laid, for example, on a flexible and cost-reducing basis, "under the rolling wheel" - i.e., without interruption of rail traffic.