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Bayflex® / Durflex® in the railway tracks

Innovative solutions are still required to reduce the high level of noise and structure-borne sound in the vicinity of railroad tracks. Tougher regulations mean that, in addition to noise protection walls, alternative forms of track construction are being sought. The innovative Durflex® solution has been developed by FRENZEL-BAU in close collaboration with Bayer MaterialScience and Hennecke GmbH. This system reduces structure-borne noise directly at the source while also cutting maintenance costs.


		Ballast tracks are very commonly used for conventional track construction. Over the course of time the ballast stones are worn down and shift due to the dynamic forces generated by the trains passing over them. Depending on the intensity of rail traffic, track ballast therefore needs to be tamped every four to six years. In addition to the associated costs, this can also result in undiserable track closures. The dynamic forces generated by trains also cause noise emissions and vibrations that local residents justifiably complain about.

Shortly after foaming, the polyurethane system is completely cured, and the track is ready for operation again.

Key advantages:

Very effective reduction of vibrations (approx. 40 %) and improved noise absorption (up to 3 dB).
Longer service life, lower maintenance costs and fewer track closures thanks to the fact that Durflex® reduces the movement and wear of ballast stones, thereby preventing superstructure compression.
Design based on conventional ballast technology but with enhanced properties.
Can be used on both new and existing sections of track.
Durflex® is made from the environmentally friendly Bayflex® foam system and ballast stones.
Good adhesion between ties and ballast material prevents horizontal displacement of ties as a result of the dynamic forces generated when trains pass over them.
Excellent pressure distribution in the substructure (stresses reduced by up to 40 %).
Enhanced frost protection thanks to the polyurethane foam’s thermal insulation.
More compact designs are conceivable (restricted spaces, tunnels etc.).