Search

Fibre-reinforced foamed urethane (FFU) composite sleepers and bearers are safety-critical components installed in complex railway switches and crossings. Not only does they need to provide vertical track support, the composite sleepers and bearers must also endure longitudinal and lateral actions stemming from complex wheel and rail interactions. In reality, the railway bearers at crossing noses are susceptible to coupling torsional-flexural loading. The complex non-linear behaviours have never been investigated numerically nor experimentally. It is thus necessary to comprehend torsional-flexural behaviours of FFU composite sleepers and bearers through finite element and experimental approaches. 3D finite element modelling of FFU composite beams have been established to predict the non-linear coupling behaviours. Three specimens of FFU beams have been prepared for robust experiments under each load case. Our studies exhibit excellent agreement between numerical and experimental results. The ductile failure behaviours (post yield point) have been observed from the experiments. Considerable effects of load eccentricity on the flexure–torsion behaviours of the composite members can also be noted. In addition, the load-eccentricity curves have been identified to portray the non-linear behaviour of the railway components under coupling flexural and torsional loadings. The new insights considering their load–displacement relationships, modes of failure and damage, flexural and torsional interactions are the precursors for railway engineers to design and adopt FFU composite sleepers and bearers in practice where complex wheel/rail interface generally causes coupling torsional and vertical loading conditions.

With an emphasis on the combined degradation of railway track geometry and components, a new numerical-analytical method is proposed for predicting the track geometrical vertical levelling loss (VLL). In contrast to previous studies, this research unprecedentedly considers the influence of initial track irregularities (ITI) on VLL under cyclic loadings, elastic-plastic behaviour, and different operational dynamic conditions. The non-linear numerical models are simulated using an explicit finite element package known as LS-Dyna, and their results are validated by full-scale experimental and field measurement data. The outcomes are iteratively regressed by an analytical logarithmic function that cumulates permanent settlements, which innovatively extends the effect of ITI on VLL in a long-term behaviour. For a typical heavy-haul railway operating under 30 tons axle load and 60 km/h train velocity, the result indicates that the set of ITI with the highest standard deviation (SD) of vertical profile (VP) degrades faster (37% on average) than that with the lowest SD. Additionally, our new findings reveal that the worst scenario is related to a train running at 60 km/h and carrying a load of 20 tons/axle in an uneven track whose SD of VP evolves from 3.23 mm at N = 0 (ITI) to 7.20 mm, whereas the best one corresponds to a train at 60 km/h and 30 ton axle load in an uneven track whose SD of VP downgrades from 0.48 to 1.50 mm, both at 3 M cycles (or 60 million gross tons). These findings indicate the importance of considering the ITI for predicting track geometrical VLL under cyclic loadings. Therefore, based on this research, an acceptable condition (thresholds) of ITI can be redefined for a minimum effect on VLL, which can support the development of practical maintenance guidelines to extend the railway track service life.

Interactive learning technology is an emerging innovation for future communication-aided teaching and learning that could positively enhance students' engagement and intrinsic motivation. Due to the virtue of interactive communication, classrooms are now anticipated to enable a variety of interaction-based learning technologies with diverse infotainment (a subset of "serious play") integrated with practical enquiry-based projects and case studies for employability improvement. In this paper, a comprehensive review of various teaching and learning pedagogies is assessed. Their suitability and association with infotainment and interactive technology is discussed and highlighted. In addition, a recent research activity on interactive communication is presented to form a new teaching application using interactive technology and infotainment (or edutainment) appropriate for student engagement in railway geometry and alignment design classes. The development of the integrated interactive technology and infotainment was implemented and evaluated in a postgraduate railway engineering class. Questionnaires were used to survey students' experiences in the classes with and without the technology enhanced learning. The outcome clearly shows that students enjoyed and felt they were significantly engaged in the class with the new interactive resources. Their participation and learning performance increased. Despite the favourable outcomes, the flexibility and viability of using this interactive technology still largely depends on the students' background and their previous experience.

Damages on railway sleepers due to heavy impact loads induced by the movement of trains can be reduced by improving their impact resistance. Fibre-reinforced/pre-treated crumb rubber concrete sleepers (RCSs) have the potential to display significant impact resistance to withstand a high-magnitude impact load. The ideal proportions of pre-treated crumb rubber, steel fibres, and polypropylene fibres (PFs) can be identified based on the minimum cost-to-impact energy ratio after conducting a drop weight impact test on prisms. The numerical model developed to assess the behaviour of ballasted tracks has been validated using both simulation results and field measurements. Numerical studies have been conducted on ballasted rail tracks with steel and PF-reinforced/pre-treated RCSs using LS-DYNA software. Dynamic strain rate-dependent material parameters are introduced in the numerical simulations. The nonlinear effect of higher train speeds on dynamic track responses has been highlighted in this article. Although the static load-carrying capacity and modulus of elasticity of rubber concrete are low, their dynamic performance controls the track displacements from exceeding permissible limits. The outcome of this study will provide new insights into the effects of railway concrete sleepers incorporated with reinforced fibres and pre-treated crumb rubber on railway track performance in order to ensure safety and reliability before it is put into services.

This article presents a new binocular vision method for accurate deformation measurements of flexible membrane structures. Using enhanced marker points on the membrane, the method identifies areas for displacement measurements, filtering out unwanted image features with scale-invariant feature transform and threshold correlation. It integrates Canny edge recognition and quadratic weighted averaging for precise positioning of measurement points. By comparing reference images and utilizing the principle of minimum distance between matching points, the method achieves fast matching and determines the three-dimensional coordinates of marker points, enhancing measurement efficiency and robustness. This approach has been empirically tested on membrane structures, providing new insights. The results highlight that our novel algorithm can achieve high-precision measurements down to millimeters, and its accuracy increases with the actual displacement of the membrane structure. Notably, this groundbreaking measurement method remains unaffected by the form of the membrane surface, addressing a long-standing challenge in the field.