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Sweden, Sweden

Lundberg J.,Lulea University of Technology | Bohlin A.,Andreasen AB | Syk M.,Trafikverket
International Journal of Systems Assurance Engineering and Management

Manganese crossings are widely used in the railway sector because of their self-hardening properties, but one major disadvantage is that maintenance actions using condition monitoring of internal flaws are problematic to perform. The reason is that manganese material is coarse-grained with internal reflections. In the present study, measurements on internal flaws with a spectrum of ultrasonic equipment were performed on a real manganese crossing. After the measurements, the crossing was cut up and inspected. Correlations with the measurements and the real flaws indicate that, independent of the equipment used, false echoes were common, as well as a low capacity to indicate real flaws. © The Society for Reliability Engineering, Quality and Operations Management (SREQOM), India and The Division of Operation and Maintenance, Lulea University of Technology, Sweden 2011. Source

Rodriguez E.,Lulea University of Technology | Simon V.,Lulea University of Technology | Galar D.,Lulea University of Technology | Niska S.,Trafikverket
Civil-Comp Proceedings

The study of railway electromagnetic interference seeks to determine the source of the interference or to ensure the correct operation of the equipment within adverse conditions. The complexity of railway system increases when more electronics are used. However a simple DC track circuit is still used in train detection systems in many countries, including Sweden. Most of the failures reported in the Swedish railway infrastructure are related to the detection system, making this research of interest to the railway community. By searching the Swedish failures report database for the most repetitive and probable causes of failures, the three worst case scenarios were identified: low resistance between the rails, external interference as a lightning and iron-powder-bridges in the insulated joint. They were simulated using the software CST STUDIO SUITE® (the Computer Simulation Technology Studio Suite), supported by real measurements on site. Measurements followed the current electromagnetic compatibility standards and were used to tune and validate the models, resulting in simulations very close to the real measures. © Civil-Comp Press, 2014. Source

Asplund M.,Trafikverket | Asplund M.,Lulea University of Technology | Palo M.,Lulea University of Technology | Famurewa S.,Lulea University of Technology | Rantatalo M.,Lulea University of Technology
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

The capacity demands on railways will increase in the future, as will demands for a robust and available system. The availability of a railway system is dependent on the condition of its infrastructure and rolling stock. To inspect rolling stock so as to prevent damage to the track due to faulty wheels, infrastructure managers normally install wayside monitoring systems along the track. Such systems indicate, for example, wheels that fall outside the defined safety limits and have to be removed from service to prevent further damage to the track. Due to the nature of many wayside monitoring systems, which only monitor vehicles at defined points along the track, damage may be induced on the track prior to fault detection at the location of the system. Such damage can entail capacity-limiting speed reductions and manual track inspections before the track can be reopened for traffic. The number of wheel defects must therefore be kept to a minimum. In this paper, wheel profile parameters measured by a wayside wheel profile measurement system, installed along the Swedish Iron Ore Line, are examined and related to warning and alarm indications from a wheel defect detector installed on the same line. The study shows that an increased wheel wear, detectable by changes in the wheel profile parameters, could be used to reduce the risk of capacity-limiting wheel defect failure events and their reactive measures. © IMechE 2014. Source

Jonsson J.,Lulea University of Technology | Arasteh Khouy I.,Lulea University of Technology | Lundberg J.,Lulea University of Technology | Rantatalo M.,Lulea University of Technology | Nissen A.,Trafikverket
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

Turnouts are critical units in a railway system; they perform the switching procedure that allows trains to change between routes. Monitoring the track geometry of a turnout is necessary for maintenance planning and design optimisation. Monitoring is usually done by track recording cars, however, to isolate the ageing and dynamic behaviour of the track it is also necessary to study the unstressed track geometry of the turnouts. Such measurements can be used to develop degradation models to optimise maintenance and design, thereby increasing availability and reducing life cycle cost. This paper introduces a new method to measure the vertical position of the track geometry over time during non-operational conditions (unstressed) to show track degradation. The new method includes a smart system that uses relative measurement reference points to create a better accuracy and lower costs compared with fixed reference points. It evaluates various types of measurement equipment and uses levelling equipment to measure the unstressed vertical geometry of 13 turnouts located on Swedish railway lines, with three follow-up measurements over a year and a half. The turnouts were categorised into four groups: based on their accumulated capacity in million gross tonnes (MGT) and whether they were on a straight or curved main track. Surprisingly, the first three measurements showed the geometry of turnouts on the straight main track to have a vertical elevation tendency towards the mid-section, whereas the turnouts on the curved main track had a general vertical downwards bend tendency towards the mid-section. The results also showed that a higher capacity in MGT has a greater influence on track geometry changes over time. © IMechE 2014. Source

Berggren E.G.,Trafikverket
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

Measured condition data may contain lots of information that is not efficiently used. By using techniques from the field of pattern recognition, this article outlines a methodology for eliciting new information. The methodology is demonstrated on a large set of condition data originating from track geometry quality, dynamic stiffness, and ground penetrating radar. The case study gives evidence for the importance of dynamic stiffness measurements as to determine soil- and embankment-related track problems, whereas problems originating from the upper part or the track structure do not benefit significantly. Source

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