In the Netherlands environmental legislation imposes strict limits on the maximum noise levels produced by passing trains. To meet the standards, the Silent Bridge Group (Heerema/Grootint, Edilon and Holland Railconsult) designs and constructs the so-called "Silent Bridges". The structure consists of prefabricated steel deck sections with rails embedded in cork elastomer. The design offers major advantages: continuously supported rails last longer, the bridge is easy to assemble, it needs less maintenance and it produces considerably less noise. The impressive result is that in several cases a running train on a bridge produces even less noise than a train in a similar situation on ballast track on an open line. One added advantage is that the low profile of the bridge often makes it possible to leave more headroom underneath, making the silent bridge a good option for replacing existing steel bridges. In addition, the silent bridge concept can be applied to existing structures, reducing the load on the existing bridge. The first bridge that fully exploits the Silent Bridgefi technology was built in the Netherlands in 1995.
Most railway lines in the Netherlands use single or double rail 75 Hz track circuits with an AM-coded ATP signal. The metal elements of the bridge are in close proximity to the tracks and the large conductive construction elements of the bridge attenuate the ATP signal. In case a standard set-up for the track circuit is used, the detection systems on the rolling stock may not interpret ATP code correctly. This results in an unwanted speed limit and an emergency breaking. Therefore at the moment, as a default measure separate ATP signal cables are installed in the vicinity of the rails to guarantee the functionality of the ATP system. These cables are laid in a custom made trench, resulting in large installation costs as compared to normal ATP circuits. Another disadvantage is the unpractical procedure needed during maintenance. All this is done because, before the bridge is built, it is now known how much the ATP signal is affected by the steel in the bridge.
The subject is complex, since it combines topics of civil engineering, signalling systems and Electromagnetic Compatibility. To study alternative measures, a research project was initiated by ProRail, the Dutch Infraprovider. The research was carried out in a cooperation between the Eindhoven University of Technology and Holland Railconsult.
|Title of host publication||Proceedings of World Congress on Railway Research (WCRR) 2003, Edinburgh, UK|
|Publication status||Published - 2003|
|Event||conference; World Congress on Railway Research, Edinburgh, Scotland; 2003-09-28; 2003-10-01 - |
Duration: 28 Sep 2003 → 1 Oct 2003
|Conference||conference; World Congress on Railway Research, Edinburgh, Scotland; 2003-09-28; 2003-10-01|
|Period||28/09/03 → 1/10/03|
|Other||World Congress on Railway Research, Edinburgh, Scotland|