Railway sleepers are safety-critical and essential components in a ballasted railway track system. Sleepers could principally be made of different materials, such as, timber, steel, concrete, composite and plastic. The deterioration process of sleepers depends largely on the materials of which they are made. The most popular material for manufacturing sleepers nowadays is concrete. In very recent years, a new type of railway sleeper has been developed using composite and plastic materials. These plastic sleepers have been trialled as bridge transoms and, to a limited extent, as switch and crossing bearers. A limited application of composite (a combination of cement, steel and plastics) to bridge transoms can also be seen. At present, there is no unified design method or standard for these new plastic and composite sleepers and bearers. The lack of design information can compromise public safety. This paper thus highlights the design aspects for plastic and composite sleepers in comparison with traditional materials. It reveals that limit states design concept is the most optimal approach for sleeper design and manufacture. The insight will help rail asset owners and managers establish predictive and condition-based track design and maintenance.

The paper undertakes analysis of the dynamic impact of a rail vehicle on various types of a railway infrastructure with particular focus on the phenomenon of threshold effect within the transition zones of an engineering facility. The problem of locally variable stiffness of the railway infrastructure, which in turn could lead to the accelerated infrastructure degradation, is identified. Using the analytical and numerical background, the computational model is presented, based on which, it could be possible to determine the impact of the various rail support on the dynamic response of the entire infrastructure. The dynamic load, caused by the passage of the multiaxle rail vehicle, is taken into account in the paper. The fourth-order differential equation is solved by using the finite differences method with application of the numerical MATLAB script. The created numerical algorithm and a number of calculations allowed the formulation of several solutions that could reduce the dynamic impact of the rail vehicle on the railway surface within the transition zones. In the paper, theoretical results are compared to the field measurements conducted on a real dynamically loaded rail. Field experiments have been carried out on the railway track in operation. The vertical displacement of a rail, dynamically loaded by various types of rail vehicles passing by (both passenger and freight trains) has been investigated. Researches have been carried out in the area of transition zones of engineering facilities. Test points have been selected in places where there is a sudden change in parameters of the track structure (e.g., a change from concrete sleepers to wooden sleepers). Based on conducted researches it has been possible to validate results obtained from the numerical calculations.

The presented article concentrates on the influence of various concrete additives in the form of fibers on the mechanical parameters of concrete so as to obtain the effect of gradual changes in these parameters, which is very important in the transition zone of the railway track. Steel, polymer and glass fibers, as well as concrete without additives, were accepted for the study. The effect of additives on the consistency of the mixture, compressive strength, frost resistance and elastic modulus was studied. The research concerned concrete samples and models of elements of the ballastless railway surface, i.e., track slab and concrete block supports. The track slab model was made of concrete without additives, while the models of supports were made both without and with additives. The studies were carried out in laboratory conditions. As a result, the tested concrete samples with various additives were ranked so that they could be used as a material for elements of the railway surface in the transition zones of engineering facilities on railway roads, which is important from the point of view of reducing the threshold effect occurring in these zones. Detailed laboratory tests were presented, the results of these studies were discussed, and final conclusions were drawn regarding the technology of materials and the methodology of constructing the transition zones of the railway surface in order to avoid or at least reduce the threshold effect existing in such zones.

The article is about the issue of the influence of ballast resistance on the stability of the Continuous Welded Rail. The ballast resistance affects both the longitudinal and transverse displacements. It depends on the quality of the ballast, the degree of its compaction and contamination. The article contains an analysis of the impact of ballast resistance on the track based on the Finite Difference Method. The calculations showed that the resistance value directly affects the allowable critical force and the maximum temperature rise in the rail that does not endanger the safety of railway traffic.

The article is about the issue of maintaining a contactless track. Due to the forces occurring in the track, arising from both temperature changes and from rolling stock rolling on the track, it is necessary to monitor a displacement of rail tracks and stress in rails. The article presents a summary of the methods for monitoring the contactless track condition. The comparison of the methods was also presented, showing the pros and cons of each of them. Keywords: contactless track, contactless track buckling, track stress