Bayer MaterialScience develops Noise protection system through foamed track ballast layer

FRENZEL-BAU GmbH & Co. KG, a specialist in rail engineering solutions headquartered in Freden, Germany, has teamed up with Bayer MaterialScience AG and Hennecke GmbH to devise a completely new solution to the problem of noise pollution caused by the movement of passenger and freight trains for residents in close proximity to railway routes.

In this application of the Durflex® system of FRENZEL-BAU, the cavities between the ballast stones in the track bed are completely filled with the Bayflex® elastic polyurethane foam system from Bayer MaterialScience. This prevents the movement of the ballast stones, which occurs as a result of the dynamic forces generated when a train passes over them. This in turn increases the durability of the ballast superstructure considerably and absorbs the structure-borne noise at the point where it is usually generated.

In the past, rail network operators have tended to build noise protection walls to reduce noise levels. However, this solution is expensive and the walls themselves are often considered intrusive. What's more, there is often no space to build noise protection walls in city centres.

Bayer has introduced an innovative track superstructure system Durflex with long-lasting flexibility. The cavities between the ballast stones in the track bed are completely filled with the Bayflex elastic polyurethane foam system from Bayer MaterialScience. ''This prevents the movement of the ballast stones, which occurs as a result of the dynamic forces generated when a train passes over them. This in turn increases the durability of the ballast superstructure considerably and absorbs the structure-borne noise at the point where it is usually generated,'' explains Jürgen Frenzel, proprietor of FRENZEL-BAU. The system can be used both for building new sections of track and upgrading existing stretches.

The German rail network increased incresed the traffic its trains carried to to 114.6 billion ton kilometers in 2007, up 7.1 per cent on the previous year and passenger transportation to 79.1 billion passenger kilometers, demonstrating the growing reliance on rail traffic in Germany.

Recently, participants to  a symposium organised by the German Association of Railway Engineers in Berlin had the opportunity to see for themselves the benefits of the Durflex track superstructure system. This event for experts from railway infrastructure companies, planning offices, the German Federal Railways Authority and other institutions, focused on the application of the system in local public transportation.

The symposium included a series of presentations on the topic and a practical demonstration of the system on a section of railway operated by the Berlin Transportation Company (BVG), which operates an extensive rail network in the capital, covering some 350 kilometers of overground and underground tracks. Complaints from residents about the noise generated by the rail traffic was one of the factors that prompted the joint research project between BVG and FRENZEL-BAU.