Improving rail safety in Europe

The European rail industry is in a state of rapid transformation aimed at meeting the increasing safety, environmental, societal and economic demands set for modern rail transport. Efficient transport and mobility are the lifeblood of the European economy and an indispensable factor in European competitive and sustainable growth, enhancing communication, economic growth and social stability.

As with any modern transport network, European transport must have, as a key component, a well coordinated, smoothly functioning international rail system. The main challenge for the European rail industry is to develop maximum passenger/customer value without compromising safety. Trains must be safe, clean, reliable, and on time, both for passengers and goods. Improved services would give rail transport a huge competitive edge, making it the best way to combine low travel time with easy accessibility to both leisure and professional hubs, whilst maintaining environmental impact to a minimum.

Safety is an important factor that plays a role in rail transport. It’s possible for any number of causes to impinge on rail safety including operator error, track and wagon integrity. Specifically, wheel set defects have been associated with rail accidents, damage to the network, delays and unnecessary costs for many years. Their effect however has become more significant over the last few years as train speeds have increased and rail networks have become busier. Well known incidents attributed to failure of wheel sets include catastrophic derailments in Rickerscote, UK in 1996, Eschede, Germany in 1998, and the S-Bhan derailment in Kaulsdorf, Germany 2009. When the accidents happen, they send shock-waves throughout society and the rail industry, reducing the public confidence in rail transport. Disruption due to defects in the wheel sets of rolling stock causes great consternation, because failures have randomness and are not directly controllable.

The safety and economic implications of wheel set defects was underestimated by the rail industry until recently. With the pressure for more reliable and punctual rail transport the problem of faulty wheel sets has become apparent. This has led to the implementation of rules on the maximum length and depth of wheel set defects that may stay in service. Extensive experimental results have shown though, that some non-condemnable wheel set defects can still cause damage to the rails or lead to catastrophic failures. As an alternative, the rail industry has developed devices for automatically detecting wheel set defects. However, significant improvements are currently needed in order to increase the reliability of the existing detectors and systems currently used in rolling stock maintenance.

Apart from the application of on-line/track side detectors, inspection of wheel sets takes place mainly during production and regular maintenance intervals. Inspection is commonly carried out using ultrasonic testing (UT). Although this technique is relatively reliable, UT may still miss small surface breaking defects which can then lead to catastrophic failure of the wheel set if they remain undetected. It is therefore necessary for the rail industry, when public safety is involved, to make every endeavour to ensure that potential problems are pinpointed at an early stage, by researching new inspection methodologies.

There is currently no available technology that can be deployed in order to inspect wheel sets with 100% reliability. However, this deficiency is being addressed through research and development of new inspection technology in a collaborative research project called SAFERAIL for which I am the project manager. SAFERAIL comprises several European rail transport providers, manufactures of inspection equipment and research organisations. The consortium is currently researching and developing the necessary technology for a more reliable and accurate track side inspection of wheel sets, as well as for a more accurate inspection during their maintenance and production. After project completion in September 2011 it is hoped that the technology can then be taken down the path for full commercialisation.

Of course development of suitable inspection equipment is only the beginning. What must follow after the research into any new methodologies (including those developed in SAFERAIL) is to benchmark the techniques developed, compare them, validate and develop a commonly accepted procedure, in order to lead to improved European inspection standards and ultimately contribute to improvement of rail safety.

Dr Ian Nicholson is principal project scientist at TWI. His current research interests deal with non destructive testing methods, system integration and automating NDT inspection. Management of collaborative research projects are also included in his activities, including leading the EU FP7 part funded collaborative project titled SAFERAIL - Development of novel inspection systems for railway wheel sets. For further information please visit the SAFERAIL website.

Published: Monday, 16th August 2010