The European high-speed train network is covering more and more ground. However, conventional track beds are often unable to cope with the mechanical stress. The HIPERTRACK project offers alternatives which researchers investigate on a test track in southern Italy.
No matter how fast modern trains such as the German ICE, the French TGV or the Italian ETR may be able to travel – they can only show off their prowess to the full if the track bed is up to the task. The proposed speeds of 300 kilometers or more per hour are too much for conventional rail track beds, so there is an increasing tendency to build dedicated rigid rail systems made of concrete. However, these should be designed for optimum performance right from the outset. For this reason, the European Rail Research Advisory Council (ERRAC) drew up the Strategic Rail Research Agenda 2020. It lays down the prime requirements for expanding and modernizing the railway network and sets the course for the future. The EU mandate was to develop, implement and assess a new track system – the High Performance Rail Track (HIPERTRACK).
After investigating the mechanical and acoustic behavior of the existing tracks under stress and determining the damage mechanisms that occur, the eight project partners from Italy, Austria, Slovenia and Germany embarked on the construction of a 300-meter test track near the town of Foggia in southern Italy. They implemented two models which had also proven to be the best in terms of cost. For approximately a year now, a long-term monitoring system has continuously provided readings via remote technology. Both track variants are made of prefabricated concrete slabs and are equipped with the newly designed continuous rail support (CRS), an elastomer layer located between the rail and the fasteners on the slab. This absorbs the vertical oscillations of the rail, the greatest source of unwelcome noise – which can otherwise only be overcome by constructing expensive sound insulation walls in the vicinity of residential areas.
Another interesting discovery was that the construction materials are now subjected to considerably lower stress than on ballast track beds. As a result, the spacing between the track fasteners could be increased from 65 to 80 centimeters, reducing the number of these connection points by one fifth. “We were delighted that the Italian state railway company, which is considered to be very progressive in terms of technology, accepted major elements of our improvements,” sums up Michael Kieninger, project manager at the Fraunhofer Institute for Structural Durability and System Reliability LBF. “The results fulfill the ERRAC specifications to a particularly high degree. This is why we are confident that they will help to modernize the European high-speed railway network.”