3.1.4.5 BTE slab track system The BTE system is a concrete supportive layer (CBL) with individual support points over a hydraulically bonded layer (HBL), very similar to BES system. A two-level plate machine system is used to achieve the desirable geometry of the concrete slab layer (CBL) (UIC report15). Two different rail fastenings have been used for this system, Ioarg 336 and ERL (BWG). The concrete areas, where the rail fasteners are located, are manufactured with extra strength. Details of the BTE design system are shown in figure 55.9).