The continuous fibreglass rovings in FFU provide the customer with a far greater consistency of the material behaviour in practical use when compared to natural wood.
Significantly better technical characteristics than those of natural wood make the technical and economic optimisation of the cross-section possible. This applies in particular to bridges and switches.
Since the 1980s, Japanese trains travel over 14 cm high FFU sleepers at switches.
In 2015, Munich Technical University proved that this works safely in Europe, too, on ballast with a 22.5 t axle load and at speeds up to 200 km/h.

In the ballast bed the underside of the FFU synthetic wood sleeper behaves just like a wooden sleeper.