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Rail corrugation poses a significant threat to train running safety in the field of railway engineering. Therefore, this study employs numerical analysis to investigate the evolution and formation mechanism of rail corrugation in high-speed railways (HSR). Firstly, a three-dimensional (3D) vehicle-track coupled dynamics (VTCD) model is established, which considers the longitudinal wheel-rail (WR) coupling relationship more adequately. Then, by integrating the USFD wear model into this 3D VTCD model, a long-term iterative wear model is developed to reproduce the corrugation evolution process. The predicted corrugation exhibits two distinct wavelength components and closely matches the sample obtained from China's HSR, validating the established model in terms of reliability. Furthermore, the formation mechanism of these two wavelength components is investigated by analyzing the harmonic behavior of vehicle-track coupled systems (VTCS) and the evolution law of rail corrugation under different calculation conditions. The findings reveal that the 3rd-order vertical rail local bending mode (RLBM) between two wheelsets of a bogie (TW-B) is the primary factor contributing to the formation of the long-wavelength component of rail corrugation. The discrete supports of the fasteners do not affect the 3rd-order vertical RLBM, which can be stably excited. Moreover, the vertical rail vibration has a substantial coupled effect on the longitudinal WR creep. When the 3rd-order vertical RLBM is excited, the coupled effect and the negative longitudinal WR creepage together evidently promote the formation of the short-wavelength component of rail corrugation. [ABSTRACT FROM AUTHOR]

This study aims to empirically examine the effect of high-speed railways (HSR) on the urban agglomeration of producer services. We analyze China's urban panel data from 2003 to 2019 using a time-varying Difference-in-Differences (DID) model. Our findings indicate that as HSR networks expand across 282 cities, producer service agglomeration decreases significantly, resulting in a more balanced spatial distribution of these services. The analysis of heterogeneity indicates that low-level producer services have a greater impact than their advanced counterparts, particularly in the central and eastern regions. Our research highlights the significance of coordinating industry specialization, city levels, and regional dynamics in China's future producer services development. The evidence indicates that the introduction of HSR systems contributes to the harmonization of the distribution of producer services to the advantage of both central and peripheral cities. Moreover, our findings highlight the potential for high-speed railways to promote sustained and robust economic growth by facilitating efficient factor flow. The study integrates knowledge economy perspectives with transportation advancements in this context, underscoring the intricate relationship between urbanization, economic dynamics, and knowledge-driven development. [ABSTRACT FROM AUTHOR]

Pile-supported embankments are typically composed of soil-rock mixtures. within these structures, while the soil arching effect is crucial for effective load transfer, it remains incompletely understood, particularly when the impact of various loading conditions needs to be considered. This study investigates this problem using a 1 g physical experimental modeling approach. Subsequently, a DEM model for a full-scale pile-supported embankment of high-speed railways, accounting for multiple pile interactions, is established with proper model calibration. Numerical simulations are conducted to explore the load transfer mechanism and soil arching processes under self-weight, embankment preloading, and train-induced dynamics influences. The findings indicate that under self-weight, fully developed soil arching structures can be achieved with a sufficiently high embankment height, although they can diminish as the soil-pile relative displacement increases. However, during embankment preloading processes, represented by static loading, pressure can be transferred from pile caps to subsoil regions, potentially compromising the integrity of soil arching structures. Train-induced dynamics effects are modeled as cyclic loading inputs, revealing that an increase in loading frequency leads to weakened dynamic pressure fluctuation for both pile caps and subsoil regions, with a limited impact on the valley values of the pressures. Additionally, a higher loading frequency corresponds to smaller accumulated loading plate settlements. [ABSTRACT FROM AUTHOR]

High-speed railway bridges are subjected to normative limitations concerning maximum permissible deck accelerations. For the design of these structures, the European norm EN 1991-2 introduces the high-speed load model (HSLM)—a set of point loads intended to include the effects of existing high-speed trains. Yet, the evolution of current trains and the recent development of new load models motivate a discussion regarding the limits of validity of the HSLM. For this study, a large number of randomly generated load models of articulated, conventional, and regular trains are tested and compared with the envelope of HSLM effects. For each type of train, two sets of 100,000 load models are considered: one abiding by the limits of the EN 1991-2 and another considering wider limits. This comparison is achieved using both a bridge-independent metric (train signatures) and dynamic analyses on a case study bridge (the Canelas bridge of the Portuguese Railway Network). For the latter, a methodology to decrease the computational cost of moving loads analysis is introduced. Results show that some theoretical load models constructed within the stipulated limits of the norm can lead to effects not covered by the HSLM. This is especially noted in conventional trains, where there is a relation with larger distances between centres of adjacent vehicle bogies. [ABSTRACT FROM AUTHOR]

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks, provide safe and smooth rides, and reduce the maintenance frequency. In this paper, the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in Abaqus. It is then compared to the performance of a ballasted track. First, slab and ballasted track models are developed to replicate the full-scale testing of track sections. Once the models are calibrated with the experimental results, the novel slab model is developed and compared against the calibrated slab track results. The slab and ballasted track models are then extended to create linear dynamic models, considering the track geodynamics, and simulating train passages at various speeds, for which the Ledsgård documented case was used to validate the models. Trains travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil, considering the issues associated with critical speeds. Various train loading methods are discussed, and the most practical approach is retained and described. Moreover, correlations are made between the geotechnical parameters of modern high-speed rail and conventional standards. It is found that considering the same ground condition, the slab track deflections are considerably smaller than those of the ballasted track at high speeds, while they show similar behaviour at low speeds. [ABSTRACT FROM AUTHOR]

High carbon emission efficiency is an important guarantee for achieving the goals of "carbon peaking" by 2030 and "carbon neutrality" by 2060. Based on the panel data of prefecture-level cities from 2003 to 2018, the spatial difference-in-difference model is used to empirically test the spatial spillover effect of the opening of high-speed rail (HSR) on urban total factor carbon emission efficiency (TFCEE). The results show that the spatial correlation of TFCEE between regions is positive, and the opening of HSR has a significant positive spatial spillover effect on TFCEE. The conclusion is still valid after a series of robustness tests. We further employ a mediating effects model to verify that green technology innovation and labour resource mismatch are two important channels of influence for the opening of HSR to improve TFCEE. The heterogeneity analysis shows that the opening of HSR significantly promotes the higher development level and the provincial capital TFCEE. [ABSTRACT FROM AUTHOR]

The construction of high-speed railways and the smart city pilot (HSR-SCP) demonstrates the synergy of traditional and new infrastructure upgrades, which has a significant influence on the economic transition and green economic growth. However, little study has been conducted on the impact of HSR-SCP synergy on carbon emissions. Applying China's prefecture-level panel data, this paper, therefore, attempts to investigate the effect of HSR-SCP on carbon emissions and uncover its in-depth mechanism through the multi-period difference-in-differences model. Notably, an appropriate instrumental variable for HSR-SCP is introduced to address possible endogeneity. The main conclusions indicate that the construction of HSR-SCP plays an essential role in cutting carbon emissions, which is still valid after adopting the instrumental variable method and some robustness tests. Furthermore, green technology innovation plays a crucial intermediary role in that relationship. Finally, the carbon reduction effect of HSR-SCP is significant in Mid-Eastern China and cities with high population sizes and administrative levels, but not in other cities or regions. The research conclusions demonstrate the significant synergy of traditional and new infrastructure upgrades on carbon reduction and provide an empirical foundation for developing countries to realize low-carbon development through optimizing smart infrastructure and promoting green technology innovation. [ABSTRACT FROM AUTHOR]

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Severe industrial pollution is puzzling human health in the world. How to reduce industrial pollution is worth to be concerned about. Some studies have verified that high-speed railways (HSRs) can directly reduce environmental pollution via green technology. However, the indirectly environmental reducing effect of the HSRs from the regulation effect perspective is rarely explored. To address this research gap, this study used information asymmetry theory and the promotion tournament theory to examine the relationship between high-speed railways (HSRs) and industrial pollution by focusing on the mediating role of environmental regulations and the moderating role of officials' political promotion incentives. Based on a sample of 113 prefecture-level cities, with balanced panel data in China from 2009 to 2017, using the difference-in-differences model, the results show that HSRs can reduce industrial pollution by 22.68% on average. The mechanism is HSRs that can improve the environmental regulation, which plays the mediating effect to further reduce industrial pollution. Additionally, high officials' political promotion incentives can strengthen this mediating effect. A propensity score matching with the difference-in-differences model and the instrumental variable method is used to solve endogenous problems, and a placebo test and a parallel trend test indicate that these results are robust. This study suggests some policy implications on developing environment-friendly transportation and improving environmental regulations to reduce industrial pollution. [ABSTRACT FROM AUTHOR]

High-speed railway engineering in mountainous areas suffers from occasional poor geological conditions, rugged topography, and complex hydrographic conditions. It is an important means of ensuring its safe operation to conduct real-time remote monitoring and analysis of the subgrade structure condition. Through analysing the stress characteristics of the mountainous subgrade, a complete monitoring system has been built and a corresponding software platform for datum acquisition and analysis has also been developed. After selecting a typical mountainous high-speed railway subgrade located in Hunan Province as the test section, the real-time monitoring of the subgrade structure in a static settling period, joint commissioning period, and an operational period was conducted and the primary condition datum was obtained. It is found that the dynamic response parameters have relatively slow attenuation velocities and the influencing depth of the high-speed train loads was about 4–5 m; when the structural state of the mountainous subgrade is healthy, subgrade deformations are small and, compared with the dynamic response datum of the subgrade in plain areas, the dynamic response of the mountainous high-speed railway subgrade was consistent. However, the long-term dynamic response and deformation of such mountainous subgrades still needs to be monitored, and analysed, continually. [ABSTRACT FROM AUTHOR]

Introduction: Elected officials and practitioners generally believe that - along with gains in time, environment, and roadway safety - the local economic impacts brought by high-speed railways (HSR) could be a major ingredient in socioeconomic appraisals. However, academic studies have shown mixed results. Methods: This article reviews the various channels through which HSR may impact the local economies. We break down the economic effects by stages of the projects' lifetime and we question the existence of these impacts with an eye towards empirical evidence from the abundant academic and 'grey' literature. Results: Outside the 'construction effects', that constitute a broad consensus, studies find both the existence and the absence of impacts of HSR, whether these are short-term effects on local productivity and the geography of consumption (through tourism or extended stays) or long-term effects on the relocation of businesses and households and ultimately local growth patterns. Results show great variability as economic effects are conditional upon a set of other factors such as city size, industry structures, amenities, and distance from the urban core. Conclusions: The main difficulty is being able to identify empirically to what extent new infrastructures have affected variations observed in the field, and not the opposite. We believe that making progress on these questions requires clarifying which model of local development is to be used and what kind of development is the goal of public policy. [ABSTRACT FROM AUTHOR]