Derailment Detectors Help Avoid Serious Freight Train Accidents

Knorr-Bremse demonstrates effectiveness in field test

With the help of elaborate derailment tests Knorr-Bremse, the world’s leading manufacturer of braking systems for rail and commercial vehicles, has demonstrated the effectiveness and operational reliability of a new generation of freight car derailment detectors. On the site of a former marshalling yard in Berlin-Schoneweide the company, together with rail vehicle specialists from Berlin Technical University, derailed a train consisting of a locomotive and three tank cars – once with empty cars and once carrying 50,000 liters of water.

Derailment detectors are installed above freight car bogies. When a bogie derails, they detect the resultant vibration and automatically trigger emergency braking. In the past, accidents often occurred because derailments behind the locomotive went unnoticed by the train driver. Derailed cars were then often dragged over several kilometers before reaching a set of points or an obstacle that caused one or several cars to roll over, catch fire or explode. The most notorious case involved an explosion of tank cars in Zürich-Affoltern in 1994 that seriously injured three people and caused damage worth several million marks.

The Swiss Railways (Schweizerische Bundesbahnen – SBB) subsequently introduced derailment detectors for transportation of dangerous goods. Initially there were occa-sional cases of false tripping, but since Knorr-Bremse supplied an optimized version of the detector no such cases have recurred. This new generation of detectors has now also been successfully tested under real conditions. Field testing by SBB has also pro-duced good results.

The Swiss Federal Transport Authority (Schweizer Bundesamt für Verkehr) recom-mends the general use of derailment detectors for transportation of dangerous goods. On November 21, 2007 in Zagreb, the RID Committee of Experts on the Transport of Dangerous Goods decided on Europe-wide introduction of detectors for certain catego-ries of dangerous goods from 2011 onwards. A risk assessment on the Swiss rail network has revealed that some 80 per cent of accidents resulting in major spillage of dangerous goods are caused by derailment. And in some 40 per cent of all cases the train driver is not initially aware that derailment has occurred.
The Knorr-Bremse Group is the world’s leading manufacturer of braking systems for rail and commercial vehicles.

For more than 100 years now the company has pioneered the development, production and marketing of state-of-the-art braking systems. Other lines of business include automatic door systems, rail vehicle air conditioning systems and torsional vibration dampers for internal combustion engines. In 2006 the group posted sales of €3.1 billion and employed a workforce of 13,000.

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