To make line construction possible on challenging geologies, the NFF system has a bridge-like design rather than lying with its full surface on the ground. As a rule, it consists of injection piles serving as isolated foundations firmly connected to rigid portal systems. Firmly attached to these are precisely positioned longitudinal bearer units (LTEs) made of precast concrete. These LTEs consist of two longitudinal sleepers with three cross connections over the portal systems, thus creating a precast “rail bearing grid.” The rail fasteners are ready-bolted to the longitudinal sleepers.

To obtain approval from Deutsche Bahn AG, the NFF system has been exhaustively tested and put through its paces. A test line has therefore been in operation at the plant site of Rheinkalk AG in Wülfrath since May 2008. The existing ballast track was converted to the NFF system over a length of about 120 m. The extremely inhomogeneous soil with its strong variations in load-bearing capacity was ideal for testing the system. The track is exposed here to axle loads up to 22.5 t and train loads of approximately 1800 t. Measurements conducted by the University of Duisburg-Essen showed that no appreciable settlement or bending occurred over the entire period.

The new slab track system is being presented among other things at InnoTrans, the International Trade Fair for Transport Technology, which is taking place in Berlin from September 21 to 24, 2010. The many advantages of this pioneering innovation will be demonstrated on a scale 1:2 model.