No abstract

The lack of lateral resistance in a curved railway track can produce misalignment problems due to the centrifugal forces when the trains pass through. Moreover, most of the times continuous welded rails (CWR) are used in nowadays railway tracks, which can induce the track buckling as a result of thermal loads caused by high temperature gradients. A new sleeper has been designed to provide higher lateral resistance of the track. A finite element model has been developed to analyze the lateral movements of an actual curved track subjected to lateral resistance problems. Then, variations on the finite element model have been made to study the response of the track when different sleepers are used. Thus, the performance of the different sleepers in the modeled track has been analyzed, resulting that the inclusion of the new sleeper in the track can improve the lateral resistance between 39 and 55 % with respect to a track with conventional sleepers made of wood or concrete.

Currently, political policies aimed at curbing the abuse of natural resources have given rise to a conscientiousness leading to the reevaluation of wastes. Wastes generated from previous mining operations greatly impact the environment, often leaving a legacy of elevated concentrations of heavy metals in the surrounding soil and water. In this study, two types of waste from the mining district of La Union (Spain) were used to study their use as a component of road wearing courses. The physical and mechanical characteristics were determined to identify the optimal content of bitumen, as well as the fatigue resistance using the four-point beam fatigue test, in all the mixtures manufactured. The mine tailings exhibited adequate physical and mechanical properties to be utilized as a coarse aggregate for a wearing course. The results indicate that one of the studied mine tailing forms could be used as a wearing course component, since it has properties similar to a control mix that is typically used in wearing course construction.

New mobility needs in urban areas combined with eco-friendly transport modes development and urban integration requirements have promoted urban tram lines. This urban transportation system provides important benefits but also damaging effects. Among these effects, vibration and noise may be highlighted. This may cause an important impact for both residents and structures located in the surrounding areas. In order to mitigate these inadequate effects, bituminous mixtures with different percentages of crumb rubber or Polyethylene Terephthalete are proposed in this research to substitute the concrete in the slab track design. Different laboratory tests were conduced so as to check the good mechanical and physical properties of these mixtures according to the European Normative. Finally, a stone mastic asphalt mixture with 0.5 %wt of Polyethylene Terephthalete is proposed as a new material with high vibration attenuation capacity and, moreover, a high stiffness which avoids excessive track deflections.