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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJzdWJqZWN0aWQiIHZhbHVlPSIxNzc5IiAvPjxwYXJhbSBuYW1lPSJkYXRlaW4iIHZhbHVlPSIyeWVhcnMiIC8+PHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjxwYXJhbSBuYW1lPSJ0ZXJtc2xvZ2ljIiB2YWx1ZT0ib3IiIC8+PHBhcmFtIG5hbWU9ImxvY2F0aW9uIiB2YWx1ZT0iMCIgLz48L3BhcmFtcz48ZmlsdGVycyAvPjxyYW5nZXMgLz48c29ydHM+PHNvcnQgZmllbGQ9InB1Ymxpc2hlZCIgb3JkZXI9ImRlc2MiIC8+PC9zb3J0cz48cGVyc2lzdHM+PHBlcnNpc3QgbmFtZT0icmFuZ2V0eXBlIiB2YWx1ZT0icHVibGlzaGVkZGF0ZSIgLz48L3BlcnNpc3RzPjwvc2VhcmNoPg==" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Effects of wind barriers on the running safety of trains on bridges under different turbulence intensities</title>
      <link>https://trid.trb.org/View/2668878</link>
      <description><![CDATA[Wind barriers (WBs) serve as a practical approach to enhance the operational safety of trains running on bridges exposed to strong crosswinds. However, the wind environment at bridge sites located in complex mountainous regions often exhibits pronounced high turbulence characteristics. This study investigates the actual protective performance of WBs in such highly turbulent environments, focusing on their aerodynamic shielding effects under varying turbulence intensities (Iu). Wind tunnel tests were conducted to examine the aerodynamic characteristics of the train-bridge (TB) system under different wind conditions, with Iu ranging from 4.88% to 13.47%. Based on the experimental data, coupled wind-train-bridge (WTB) dynamic response analyses were conducted to quantitatively assess how different Iu influence the operational safety of trains. The results demonstrate that the unsteady aerodynamic loads induced by high Iu adversely affect train operational safety. Installing WBs effectively mitigates these detrimental effects. However, their protective performance is significantly influenced by Iu, and the safety indices deteriorate under highly turbulent conditions. This study emphasizes the importance of accounting for the actual turbulence characteristics of the wind field in WB design. The findings offer theoretical guidance for the wind-resistance optimization of long-span railway bridges in mountainous regions.]]></description>
      <pubDate>Tue, 12 May 2026 09:11:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2668878</guid>
    </item>
    <item>
      <title>Access door-to-door: An intercity efficiency and distributional analysis of the costs of travel by plane, train, and automobile</title>
      <link>https://trid.trb.org/View/2698801</link>
      <description><![CDATA[Existing studies typically evaluate air travel accessibility by examining either air network performance or ground access to airports in isolation. This paper offers a complementary perspective by assessing the national air travel accessibility through a door-to-door framework and comparing it against multiple modes of intercity transport. We compare four scenarios: air-only, railway-only, highway-only, and an optimal-mode scenario. The first three rely exclusively on a single mode for intercity trips, whereas the optimal-mode scenario selects the lowest-cost option among air, rail, and direct driving for each origin–destination pair. The results show that air travel provides higher accessibility and more balanced spatial equity than rail or highway travel at higher cost thresholds. Air travel also delivers clear advantages in regions with significant geographical constraints, where land-based transport infrastructure is limited. Although the optimal-mode scenario generally enhances spatial equity, it reduces within-group equity in regions characterized either by highly developed urban cores (e.g., the Yangtze River Delta in East China) or by significant geographic constraints (e.g., the peninsula areas of Northeast China).]]></description>
      <pubDate>Mon, 11 May 2026 17:11:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2698801</guid>
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    <item>
      <title>BallastAttN: Occlusion-Robust 3D Railway Ballast Characterization using Data Synthesis and Deep Learning</title>
      <link>https://trid.trb.org/View/2701226</link>
      <description><![CDATA[Accurate characterization of railway ballast is critical for track safety and maintenance; however, traditional field sampling/sieving or two-dimensional images captured are often labor-intensive and limited for a representative analysis. Three-dimensional (3D) point cloud analysis may offer a more comprehensive approach; the dense packing and heavy occlusion of ballast particles restrict image segmentation. This study introduces a novel deep learning pipeline designed for robust 3D railway ballast characterization, BallastAttN. Its core contributions include a comprehensive synthetic training data set from high-fidelity 3D scans of new and degraded ballast particles, an enhanced point cloud segmentation model upgraded with edge-aware voxelization and curriculum learning, and the novel BallastAttN partial point cloud completion model architected to reconstruct complete particle shapes from the highly incomplete views typical of field conditions. The proposed pipeline was comprehensively validated using controlled laboratory experiments with isolated and clustered configurations of real ballast particles in new and degraded conditions. The results show that BallastAttN consistently outperforms the baseline completion framework that utilizes an encoder–decoder architecture mechanism built on attention mechanisms across commonly used size and morphological properties. The performance gap widened substantially in clustered scenarios that are close to the field ballast appearance, demonstrating the model’s enhanced ability to handle occlusion. The predictions were precise in differentiating between new and degraded ballast based on morphological properties, such as 3D sphericity, the Flat and Elongated Ratio, and the Angularity Index. This study establishes a practical framework for automated ballast inspection, for example, with the use of an innovative ballast scanning vehicle developed, paving the way for more efficient and reliable railway ballast maintenance.]]></description>
      <pubDate>Mon, 11 May 2026 12:24:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701226</guid>
    </item>
    <item>
      <title>A method of economic evaluation of noise mitigation measures in urban rail transit</title>
      <link>https://trid.trb.org/View/2668533</link>
      <description><![CDATA[In addition to its many benefits, urban rail transit generates noise pollution that poses critical environmental and public health challenges. Traditional noise control strategies often rely on satisfying regulatory noise limits but do not take into account the social benefits of noise mitigation in the exposed areas. Moreover, conventional evaluation methods for railway transport infrastructure fail to provide a detailed analysis of the long-term socio-economic impact of noise reduction measures. This paper proposes a method for the economic evaluation of noise mitigation measures to enhance the sustainable development of urban rail transit, aiming to identify the most appropriate measures in terms of both cost efficiency and noise mitigation effectiveness. The main novelty lies in the combination of a single measure of life cycle cost (LCC) and monetized noise reduction to model the socio-economic impacts of the measures. The evaluation framework standardizes these impacts into measurable economic indicators, enabling direct comparisons between different measures. A case study involving a residential area adjacent to Beijing Subway Line 13 demonstrates the practical application of this approach. The cost-effectiveness of 4 m high noise barriers and rail grinding is analyzed and compared. Results show both measures have significant benefits: noise barriers incur higher initial costs but offer greater absolute economic benefits due to their superior noise reduction capabilities, and they are more suitable for densely populated areas, whereas rail grinding is recommended for extensive use in regular track maintenance due to its lower unit cost. The proposed evaluation method is verified by comparative analysis with existing methods. It provides a practical decision-making tool for urban rail noise abatement from the viewpoint of sustainability.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2668533</guid>
    </item>
    <item>
      <title>Image-traced flow behavior and frequency-dependent response of ballasted trackbed under dynamic loads</title>
      <link>https://trid.trb.org/View/2663870</link>
      <description><![CDATA[The continuous movement of ballast particles beneath the sleeper under long-term dynamic train loads is a primary factor contributing to the development of trackbed settlement, which becomes more pronounced under high-speed train operations. However, due to the concealed nature of such phenomenon, it is challenging to observe experimentally. In this study, a full-scale model test incorporating image-assisted measurement techniques was conducted. Approximately 1000 dyed ballast particles of varying sizes were uniformly distributed over a representative section of the trackbed as tracer particles. A combination of digital and high-speed cameras (recording at 1000 frames per second) was used to capture and analyze the trajectories of ballast particles under varying train speeds, axle loads and long-term loading conditions. The testing results indicate that the ballast layer remained in a stable state with limited particle migration when the loading frequency was below 15 Hz (equivalent to 273 km/h). However, once this threshold was exceeded, ballast migration increased sharply, accompanied by a noticeable loss of stability. Furthermore, a positive correlation was observed between the axle load amplitude and the extent of ballast flow. For axle loads below 8 tons, ballast migration was primarily governed by contact forces between the ballast particles. Beyond this limit, movement near the sleeper end increased sharply, indicating a shift in the controlling mechanism from contact force dominance to interaction between contact forces and boundary constraints. The varying constraint conditions then caused regionalized flow pattern beneath the sleeper, leading to non-uniform compaction within the trackbed. Furthermore, this process induced a characteristic periodic settlement development of the sleeper. The initial stage was marked by rapid settlement due to particle rearrangement. This was followed by a second increase in the settlement rate as the high-frequency energy input caused the particle skeleton to disintegrate. Finally, as a new stable skeleton formed, the settlement approached a shakedown state without further significant development.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663870</guid>
    </item>
    <item>
      <title>Numerical investigation of train-induced ground vibrations in ballastless embankments considering wheel–rail geometric nonlinearity</title>
      <link>https://trid.trb.org/View/2663869</link>
      <description><![CDATA[Predicting train-induced ground vibrations is essential for assessing the environmental impact of high-speed rail systems. However, many existing numerical models rely on simplified wheel–rail interaction formulations, which can lead to unreliable predictions due to inaccurate representation of the excitation source. In this study, a novel three-dimensional (3D) Vehicle–Track–Embankment–Ground (VTEG) finite element (FE) model is developed, explicitly incorporating rail irregularities and fully coupled wheel–rail geometric interaction. The proposed model is validated against field measurements in terms of subgrade dynamic soil stresses and ground surface vibration velocities. A parametric case study identifies two characteristic velocities. Critical Velocity I (CV I) closely corresponds to the Rayleigh wave velocity of the weakest supporting soil layer, whereas Critical Velocity II (CV II), associated with the peak maximum dynamic displacement (MDD) of track, lies between the Rayleigh wave velocities of the softest ground layer and the embankment base. Comparative analyses show that a conventional 2.5D linear FE model provides adequate accuracy under weakly dynamic conditions (V ≤ CV I) but progressively underestimates the track MDD as train speed approaches CV II. At CV II, the peak MDD is underestimated by approximately 14.6% relative to the proposed 3D nonlinear model, with about 54% of this discrepancy attributable to reduced model dimensionality and the remaining 46% to linear wheel–rail contact assumptions. Furthermore, foundation reinforcement markedly increases both CV I and CV II and reduces the peak MDD by approximately 43.5%, thereby effectively mitigating resonance-like behaviour at ultra-high train speeds. In addition, foundation reinforcement significantly suppresses ground-borne vibrations and modifies the characteristics of surface wave propagation, producing more circular wavefronts within the reinforced zone while maintaining Mach-cone-type features outside. These findings provide quantitative guidance for vibration assessment, modelling strategy selection and mitigation design in high-speed railway engineering.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663869</guid>
    </item>
    <item>
      <title>Train motion prognostics and classification from multi-source decentralised sensors using unsupervised data-driven technology</title>
      <link>https://trid.trb.org/View/2665697</link>
      <description><![CDATA[This study proposes a novel scenario to recognize railway train motions using K-means clustering and data collected by smartphone sensors. Traditional methods often depend on high-cost and maintenance intensive sensors. These methods face financial and logistical challenges which limit their widespread application. This study collects train acceleration using smartphones onboard and uses K-means to classify different train motions from the extracted features in both time- and frequency- domains. The result demonstrates that this approach not only addresses the latency with the traditional methods but also enhances the accuracy of train motion classification. This successful endeavor underscores the potential of integrating machine learning with smartphones to efficiently address railway motion classification challenges which enhances real-time monitoring and predictive maintenance.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2665697</guid>
    </item>
    <item>
      <title>Frost Heave Characteristics of Qinghai–Xizang Silty Clay: Experimental and Numerical Modeling</title>
      <link>https://trid.trb.org/View/2667267</link>
      <description><![CDATA[The station platforms of the Qinghai–Xizang Railway are subject to persistent frost heave due to severe cold, large temperature fluctuations, and groundwater-rich conditions. To investigate the governing mechanisms and evaluate mitigation strategies, a one-dimensional thermal–hydraulic coupled freezing system was developed, and staged freezing tests with unconfined water replenishment were conducted on silty clay from Chumar River Station. Three mitigation measures—conventional geomembrane, composite geomembrane, and a 20  mm gravel isolation layer—were assessed. The results show that frost heave is primarily driven by the migration of unfrozen water toward the freezing front, where a moisture-enriched zone forms and segregated ice lenses develop. After freezing, the water content below the freezing front becomes nearly uniform, while the upper soil exhibits a unimodal increase due to moisture redistribution. Among the mitigation measures, the composite geomembrane is the most effective, reducing the frost heave ratio by 5.81%, followed by the conventional geomembrane (5.21%) and the gravel isolation layer (2.12%). Numerical models successfully reproduce the observed variations in temperature, moisture, and displacement. These findings provide practical guidance for mitigating frost heave at station platforms along the Qinghai–Xizang Railway.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667267</guid>
    </item>
    <item>
      <title>Mechanical responses and reinforcement assessment of non-typical in-situ enlargement for closely spaced tunnel groups in weak surrounding rock</title>
      <link>https://trid.trb.org/View/2667258</link>
      <description><![CDATA[In weak surrounding rock, the closely spaced tunnel group in this study adopts a downward in-situ enlargement restricted to the overlapping segment between the existing and the new tunnels, where the interaction of evolving excavation paths and construction sequences markedly amplifies deformation and stability challenges. To examine the applicability of a non-typical stepwise “remove–backfill–downward enlargement” scheme (hereafter abbreviated as fill–then-excavate) for such settings, an ongoing closely spaced tunnel group in weak surrounding rock project along the new Chengdu–Chongqing Central Line was investigated. Laboratory tests were performed to characterize the mechanical behavior of mudstone interbedded with sandstone, and numerical simulations were integrated with in-situ monitoring to compare ground and structural deformations. Alternative backfilling strategies prior to enlargement and reinforcement options for the inter-tunnel rock pillar were assessed for construction optimization. Results indicate that stress–strain curves remain similar in shape across confining pressures, while triaxial strength and deformation characteristics vary markedly; bedding and sand-lens heterogeneity leads to pronounced mechanical anisotropy. Rightward advancement after backfilling induces early unloading in the upper-right transition zone, shifting the settlement center toward the upper-right and forming an asymmetric, unimodal pattern aligned with the enlargement contour. Excavation of the upper-bench core triggers a jump in circumferential displacement around the enlarged tunnel, with a peak of 7.79 mm. Distinct backfilling schemes perturb the surrounding rock at different stages and thereby affect both surface and lining deformations; the full backfill followed by unified enlargement scheme reduces crown settlement by 3 mm. Moreover, small-pipe grouting lowers crown settlement by approximately 20%, raises the cumulative vertical stress at the core of the middle rock pillar to 3.77–4.43 MPa, and—with simple procedures and low disturbance—emerges as a preferred option for reinforcing the pillar in closely spaced tunnels within weak rock.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667258</guid>
    </item>
    <item>
      <title>A digital-twin LiDAR simulator for performance assessment of railway ballast geometry inspections</title>
      <link>https://trid.trb.org/View/2667257</link>
      <description><![CDATA[High-speed railways are increasingly preferred for medium-distance travel, thanks to their efficiency and convenience. However, the growing frequency of services accelerates infrastructure wear, raising inspection and maintenance demands. To address this, autonomous inspection solutions based on LiDAR (Light Detection and Ranging) systems and onboard cameras have recently been proposed, but their testing and deployment remain challenging due to regulatory constraints and the difficulty of accessing representative railway environments. This work presents a LiDAR digital twin that realistically replicates sensor behaviour in real railway track environments. The simulator incorporates CAD (Computer-Aided Design) models of the track vehicle and sensor installation, enabling the assessment of installation-related limitations and sensor field-of-view occlusions. Two commercial sensors, the Livox Avia and Livox HAP, were metrologically calibrated using experimental data acquired on a real railway track. Good agreement between simulated and experimental data was observed, with deviations of only ≃2 points/cm2 in point density and centimetre-level differences in reconstructed ballast geometry. The digital twin was subsequently used to assess the suitability of this technology for ballast geometry measurement at different travel speeds, showing centimetre-order errors for both sensors at speeds of up to 120 km/h.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667257</guid>
    </item>
    <item>
      <title>Experimental investigation on dynamic characteristics of gravel soil filler for railway subgrade affected by varying initial moisture content</title>
      <link>https://trid.trb.org/View/2667269</link>
      <description><![CDATA[Gravel soil has been extensively applied to railway subgrade engineering, which would potentially be affected by rainfall-earthquake coupling effect during the process of long-term service, and its dynamic characteristics have a notable influence on the safety and stability of railway engineering projects. Test soil was derived from on-site railway subgrade filler, which is classified as poorly-graded gravel soil. To investigate gravel soil coarse-grained filler mechanical properties, this research conducted dynamic properties test, dynamic strength test, and static triaxial shear test for each soil specimen of different unsaturated states in proper sequence. During soil specimen consolidation process, the effective consolidation stress ratio K′c was controlled to remain constant for representing practical stress state of layered filling. The vibration loading applied in test included 12 level axial dynamic cyclic loading with gradually increasing amplitude and 1000 cycles of axial dynamic loading in turn. These research results demonstrate that (i) with vibration loading amplitude increasing, gravel soil specimens experienced this transition from small-strain elastic deformation state to intermediate-strain elastoplastic deformation state during whole experimental process, (ii) gravel soil filler possessed well dynamic characteristics under long-term vibration loading effect, the variation rule of dynamic shear stress amplitude τmax − dynamic shear strain amplitude γmax curve and dynamic axial strain amplitude ε¯a,d − dynamic axial loading amplitude σ¯a,d curve emerged approximate linear, however, damping ratio λ decreased with vibration loading amplitude increasing, (iii) moreover, the maximum values of both dynamic elastic modulus and dynamic shear modulus exhibit a polynomial fitting correlation with effective confining pressure σ′3 and pore water pressure coefficient B, (iv) gravel soil still maintained paradigmatic deformation characteristics of loose sand after the action of long-term vibration loading. Overall, this research has put forward further insights into dynamic response characteristics of gravel soil filler, which would provide basic design parameters and theoretical reference for seismic response analysis of railway subgrade.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667269</guid>
    </item>
    <item>
      <title>Hydro-thermo-mechanical analysis of early-age temperature and humidity evolution in double-block ballastless track slabs</title>
      <link>https://trid.trb.org/View/2694915</link>
      <description><![CDATA[The temperature and humidity characteristics during the concrete construction stage of the double - block ballastless track slab have an important influence on the mechanical behavior of the track slab after forming. To conduct an in-depth study on the mechanical behavior of the double - block ballastless track during the construction period, a humidity -temperature - mechanics model of the double - block ballastless track was established in this paper by using the humidity - temperature mechanics coupling method. Through numerical simulation and test, the variation laws of humidity, temperature, and mechanical behavior of the double - block ballastless track during the construction period were revealed. The test results showed that the internal temperature of the concrete track slab reached its peak on the third day and then decreased. The humidity maintained a relatively high level during the water storage curing period, and the surface humidity decreased rapidly after 14 days, forming a humidity gradient from the surface to the interior. The simulation results showed that the changes in humidity and temperature of the ballastless track slab with the concrete age were both very obvious, and at the same time, the non uniform distribution of temperature and humidity would cause the initial stress of the structure. Extrapolation results based on numerical simulation show that both the increase in the daily average temperature and the increase in the wind speed would intensify the differences in humidity and temperature between the surface and the interior of the ballastless track slab, thereby inducing greater thermal stress and humidity shrinkage stress. Therefore, during construction, measures such as covering and moisture preservation should be taken according to the changes in temperature and wind speed to reduce the adverse effects of environmental factors on the track slab.]]></description>
      <pubDate>Thu, 07 May 2026 11:02:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2694915</guid>
    </item>
    <item>
      <title>A comprehensive data-driven approach to estimate track longitudinal level from inertial measurements</title>
      <link>https://trid.trb.org/View/2669745</link>
      <description><![CDATA[Infrastructure managers rely on diagnostic trains that periodically measure track geometry and vehicle accelerations to ensure the safety of the railway network. Their runs are scheduled depending on the line priority, in order to safely monitor the evolution of track defects. However, sudden and unpredictable defect growth may happen and be missed between successive runs. Therefore, condition monitoring systems have been installed on in-service vehicles. In fact, these trains run every day along the same line, so they can provide additional information useful for maintenance practices. When trains run along conventional lines, their speed significantly changes depending on the line characteristics, and vehicle accelerations strongly depend on speed. Therefore, monitoring systems that rely on vehicle accelerations should carefully take this effect into account. In this paper, a methodology to estimate the track longitudinal level using bogie accelerations from an in-service vehicle is presented. The recorded accelerations were double-integrated to account for the speed variation, and a model-based strategy was adopted to reduce the filtering action of the primary suspension. Data were recorded during a two-year monitoring campaign along an Italian railway line. The methodology allowed for the estimation of the longitudinal level along specific track sections, considering statistical measures like the peak value. A maximum error of 1 mm was found between the estimated values and those measured by the diagnostic train (considering a defect with magnitude of 7.5 mm). Therefore, the results showed that it is possible to estimate the peak longitudinal level between the two rails using one single vertical accelerometer installed on the bogie of an in-service vehicle. The results of this research may be used to support the current maintenance strategy with daily estimations of track longitudinal level. It should be noted that specific attention was given only to this type of track geometry parameter, since it often drives maintenance operations. In the future, the possibility to extend the methodology to the estimation of different type of defects, like cross-level and twist, could be considered.]]></description>
      <pubDate>Thu, 07 May 2026 09:20:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2669745</guid>
    </item>
    <item>
      <title>Recent advances in wayside condition monitoring for railways: a comprehensive review</title>
      <link>https://trid.trb.org/View/2669744</link>
      <description><![CDATA[The demand for faster, longer, and safer railway networks has intensified the need for robust condition monitoring systems, particularly those capable of detecting rolling stock defects such as wheel flats, bearing faults, hunting movement, overloading, and unbalanced loads. Effective monitoring and timely maintenance are essential to mitigate these issues, enhancing both reliability and safety in railway operations. This paper presents a comprehensive review of wayside condition monitoring (WCM) systems. The study begins with a structured overview of WCM architectures, followed by a bibliometric analysis that highlights recent research trends in machine learning applications for railway condition monitoring. A detailed classification of rolling stock defects is provided to establish the foundation for condition assessment. The review then presents an extensive survey of commercial wayside monitoring systems currently in use, including hot axle box detectors, wheel impact load detectors, acoustic detection systems, and weigh-in-motion technologies. The various sensor types integrated into these systems are also described in detail. To bridge the gap between raw data collection and actionable insights, the paper includes a dedicated section on knowledge extraction from WCM systems. This section outlines key approaches for fault detection, diagnosis, and classification using advanced data processing methods, including signal processing and machine learning techniques. Finally, the paper identifies critical challenges such as data quality, real-time processing constraints, infrastructure limitations, and the need for generalizable models. It also discusses research gaps and suggests future directions, including the integration of edge computing, digital twin technology, and self-diagnostic capabilities to support the development of next-generation intelligent WCM systems.]]></description>
      <pubDate>Thu, 07 May 2026 09:20:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2669744</guid>
    </item>
    <item>
      <title>Thermal–environmental effects on degradation of railway ballast aggregates: a climate change perspective</title>
      <link>https://trid.trb.org/View/2669743</link>
      <description><![CDATA[Climate change represents one of the most significant challenges affecting the behavior of materials and infrastructures. This phenomenon can lead to excessive increases or decreases in temperature, heightened sandstorms, increased sulfate attacks and exacerbated freeze–thaw cycles. Among the infrastructures perennially exposed to climate change are railway tracks. In ballasted railway tracks, the ballast layer is affected by various factors such as freezing and thawing, extreme temperatures and attacks by various sulfate salts which can accelerate the degradation of ballast aggregates. Considering that most of the maintenance costs of railway tracks are associated with the deterioration of the ballast layer, the impact of climate change and environmental conditions on ballast durability is examined in the current study. To achieve this goal, a comprehensive experimental investigation was conducted through a series of laboratory tests. Specifically, the durability of ballast aggregates under various states, including environmental temperature changes ranging from − 20 °C to + 100 °C, freeze–thaw cycles, and sulfate attacks, was assessed by simulating these conditions in a laboratory environment. The durability properties of ballast in these conditions were evaluated using different indices such as Los Angeles abrasion, micro-Deval wear, crushing resistance, impact performance, and breakage potential. The results indicate that the durability performance under sulfate attacks, freeze–thaw cycles, and extreme cold and warm temperatures deteriorated by an average of 50%, 20%, 40%, and 35%, respectively. Interestingly, the obtained results also led to a series of insightful empirical formulations to estimate the ballast degradation indices accounting for the impacts of thermal and environmental conditions. These findings highlight a notable impact of thermal and environmental conditions on the durability of ballast aggregates.]]></description>
      <pubDate>Thu, 07 May 2026 09:20:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2669743</guid>
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