In order to meet market requirements, ZF offers several technical designs: These are based on the twin-tube principle, the recirculation principle, or the principle of a synchronized speed cylinder. All versions come with block safety. Electrically controlled yaw dampers are an advantage on winding rail tracks. Their damping function is switched off during cornering, which considerably reduces the contact forces between the wheels and the rails and results in considerably less wear. As a consequence, vehicle and rail maintenance costs are much lower.