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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Research on Method of Temperature Detection for Running Parts of Subway</title>
      <link>https://trid.trb.org/View/2580374</link>
      <description><![CDATA[The good condition of running parts in subway vehicles is the guarantee of safety operation for the train. Among which the key components need to be checked are motor, axle box and gear box. It is of great significance to study reliable detection methods for ensuring driving safety. In this paper, the temperature detection system of running parts is designed as a whole. According to the overall functional requirements, the system is designed in detail from two parts: hardware and software. Then, this paper focused on temperature data analysis and processing, including noise reduction, signal segmentation and feature analysis. Finally, the result of fitting temperature data using Spline function is given in this paper.]]></description>
      <pubDate>Wed, 30 Sep 2026 16:24:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2580374</guid>
    </item>
    <item>
      <title>Comparison of Onboard Condition Monitoring System Mounting Location for Freight 
Railcar Bearing Defect Detection Using Vibration Signatures</title>
      <link>https://trid.trb.org/View/2574768</link>
      <description><![CDATA[Prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that onboard sensor technology can make early and accurate detections of defect initiation in railcar bearings and wheels. Vibration thresholds were developed using the extensive history of acceleration data gathered from an accelerometer mounted at the preferred Smart Adapter (SA) location on the bearing adapter. This location is not available on many adapter types. Data acquired at alternate locations on the adapter indicates that there are systematic differences in recorded vibration waveforms that are significant enough to require compensation in order to find equivalent threshold levels. We propose a study using multiple, simultaneously sampled accelerometers on adapters at several different locations of the adapter surface, to determine the required compensation functions. This large-scale study will be conducted at the UTCRS lab but will be supplemented with field data expected to be gathered at the MxV Rail Fast Loop facility. The test will directly acquire data from (a) the SA location, (b) face-mounted top dead center (TDC) location, (c) and face-mounted at a location 45o off top-dead center (Mote). It will also be compared with statistical data from commercial vibration sensors with alternate mountings. The lab testing will take place concurrently with other previously committed experiments on a combination of healthy bearings and bearings with known early-stage and progressing defects. The outcomes of this project would include quantitative, calibrated comparisons of vibration signatures from the SA location to the alternate as well as potential improvements to existing thresholds and algorithms. ]]></description>
      <pubDate>Mon, 14 Jul 2025 18:51:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2574768</guid>
    </item>
    <item>
      <title>Effect of Long-Term Inactivity on Railcar Bearing Lubricant and Seal Function</title>
      <link>https://trid.trb.org/View/2574620</link>
      <description><![CDATA[Prior work on the effects of prolonged inactivity on rail bearing performance focused on possible effects of extended idle periods on lubricant condition and performance. Those studies utilized bearings which had been idle for three years. Normal changes in lubricant antioxidants and consistency were observed but changes did not fall outside the necessary condition for safe operation of the bearing. A controlled study of long-term idleness on lubricant characteristics began as part of that study and the research team proposes extending that work for another year. In the testing of the idle bearings received from CSX Transportation, two seal-related conditions were observed which would have some impact on long term performance. One bearing showed evidence of water intrusion as evidenced both by corrosion on the bearing raceway and behavior of samples in thermal analysis. In addition, several bearings subjected to service testing developed lubricant leaks from the metallic joint between the seal and bearing cup which is a press fit. In almost two decades of bearing life testing, the research team has never seen a leak at that location, even in bearings which had been reassembled multiple times. The proposed work would have one continuing effort and one new line of investigation. (1) The effects of extended inactivity on lubricants stored in a bearing simulator and continuously exposed to the South Texas elements would continue for another year. (2) Evaluation of effects of extended periods under load without rotation on the metal-metal interface between the bearing seal and the bearing cup. 

 ]]></description>
      <pubDate>Mon, 14 Jul 2025 18:59:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2574620</guid>
    </item>
    <item>
      <title>Ultrasonic Inspection of Reconditioned Railroad Bearing Components – Year 3</title>
      <link>https://trid.trb.org/View/2574196</link>
      <description><![CDATA[Freight rail bearings are often subjected to heavy loads such that the performance of each bearing plays a crucial role in the safe operation of the entire train. Even bearings that are properly maintained may still fail due to rolling contact fatigue (RCF) if local regions within the bearing race do not meet established effective case depth (ECD) standards. In addition, little is known about potential changes that may occur within the highest stress region after extensive service life. Ultrasonic grain scattering shows sensitivity to both microstructure and residual stresses such that nondestructive measurement methods based on diffuse ultrasonic backscatter have shown a high correlation with the overall status of the raceway. Results from the first year showed clear differences between new and reconditioned bearing cups in terms of their ultrasonic signatures. This work will be expanded to include spatial maps of raceways to identify locations that are outside the statistical bounds expected for a given part. Those locations will be identified and those parts will be tested in simulated service life testing at UTRGV for comparison with the predictions. ]]></description>
      <pubDate>Mon, 14 Jul 2025 19:01:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2574196</guid>
    </item>
    <item>
      <title>Summary of Charpy and Dynamic Tear Testing of Bolster Samples</title>
      <link>https://trid.trb.org/View/2256379</link>
      <description><![CDATA[The Federal Railroad Administration (FRA) collaborates with the Association of American Railroads’ (AAR) Coupling System and Truck Castings Committee and Transportation Technology Center, Inc. to investigate possible solutions to early-life failures of railcar side frames and bolsters. Side frame and bolster failures can be mostly attributed to either fatigue or brittle failure. Of the brittle failures, most can be attributed to marginal strength and poor impact resistance of the cast steel material. A brittle failure can occur instantaneously and under stresses that can be below the yield strength of the material. The results of Charpy (fracture toughness) and dynamic tear (progressive fracture resistance) tests of samples from seven different foundries showed the probability of brittle failures may be higher than expected. Such was the case for cars operating in colder weather because of the increased brittleness of the material in lower temperatures. The Charpy test results showed that most samples passed at the critical temperatures. The fracture surfaces could be examined for more information in the later phase of this research. The dynamic tear tests show an upward sloping trend, which may indicate that the transition period from brittle to ductile failures was somewhere between 20 °F and 60 °F. The dynamic tear test samples also indicated larger discrepancies between individual samples and between foundries. Final test results will be compiled and reviewed to recommend approaches to improve the castings. An iterative process with the foundries is expected to cost-effectively improve castings.]]></description>
      <pubDate>Sun, 01 Oct 2023 19:02:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2256379</guid>
    </item>
    <item>
      <title>Bearing Grease Degradation Related to Water Ingress and Roller Bluing</title>
      <link>https://trid.trb.org/View/2256358</link>
      <description><![CDATA[The Federal Railroad Administration sponsored a team from Transportation Technology Center, Inc. to conduct two investigations to improve the safety of roller bearing operations on railcars. The team conducted the research between September 2018 and April 2022 in collaboration with Burlington Northern Santa Fe Railway, Timken Company, and Amsted Rail Company, Inc. to provide insight into the internal state of bearings that have degraded due to grease degradation from water ingress. The tests conducted in the investigation of water ingress-related bearing grease degradation indicated a difference between bearings with “Water-Etch” and “Non-Verified” failure modes based on ferrous debris levels in the grease. This difference is due to wear of the bearing material deposited in the grease. The tests conducted in the investigation of lube stain in bearings showed lube stain does not affect any tested metallurgical material properties other than surface discoloration. The team recommends that further grease samples should be taken to allow statistical inference of other variables other than ferrous wear, including contamination, consistency, and moisture levels.]]></description>
      <pubDate>Sun, 01 Oct 2023 19:02:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2256358</guid>
    </item>
    <item>
      <title>Transformation of structure during friction stir welding</title>
      <link>https://trid.trb.org/View/1909705</link>
      <description><![CDATA[In comparison with low carbon steels, there is increased interest in the use of aluminium-based alloys as materials for the manufacture of welded structures rolling stock of railway transport. During friction stir welding aluminium-based alloy, against the background of the analysis structural transformations, issues of development hardening processes are considered. Under conditions of existence, a temperature gradient at zone of weld formation, shown degree approximation alloy to the conditions of superplastic flow and influence from presence particles of the second phase on grain size of matrix is estimated. Evaluation of the separate influence grain size of matrix and state of solid solution at total hardness of the weld showed dependence of their contributions on temperature of hot plastic deformation. As the temperature of plastic deformation of alloy at area of the weld increases, contribution to the total hardness from grain size increase and on state of the solid solution decreases.]]></description>
      <pubDate>Wed, 20 Apr 2022 16:15:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1909705</guid>
    </item>
    <item>
      <title>Railway vehicle bearings risk monitoring based on normal region estimation for no-fault data situations</title>
      <link>https://trid.trb.org/View/1883868</link>
      <description><![CDATA[A risk monitoring method based on normal region estimation (NRE) is systematically proposed for the actual situation of the lack of fault data in the condition identification and monitoring of railway vehicle bearings. First, the basic concept of normal domain theory is expounded, and the formal expression of normal domain is given. Secondly, the academic thoughts and implementation steps of risk monitoring based on NRE are summarized. Then, two algorithms based on convex hull and support vector data description (SVDD) are proposed respectively to solve the core problem of boundary estimation. Finally, the rolling-bearing vibration acceleration data was used for the experiment, and the performance of the two algorithms is compared. The results show that both algorithms are effective. In contrast, the convex hull algorithm is faster, and the SVDD algorithm is smoother and more flexible. In practical applications, the two algorithms can be selected according to different requirements of real time and accuracy.]]></description>
      <pubDate>Tue, 23 Nov 2021 11:17:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1883868</guid>
    </item>
    <item>
      <title>Selection and ranking of rail vehicle components for optimal lightweighting using composite materials</title>
      <link>https://trid.trb.org/View/1845857</link>
      <description><![CDATA[The current performance requirements for the global rail industry demand that trains are more reliable, efficient and can accommodate an increased capacity for more passengers. Lightweight construction of rail vehicles is thus required to meet these requirements. This paper has identified the key components for lightweighting of rail vehicles using fibre reinforced polymer composite materials. A methodology used to select and rank those metallic components suitable for redesign in composite, developed as part of the ACIS (Advanced Composite Integrated Structures) UK project is described. From the audit, five demonstrator components – a cantilevered seat bracket, luggage rack module, intermediate end structure, body side structure and roof structure – were identified by the consortium using the methodology. These are components that the consortium believes to be the most suitable to demonstrate the benefit of a composite replacement in terms of integration potential, lightweighting benefits and commercial viability. Furthermore, rail car body structural components, forming the primary structure of a rail vehicle, were determined to be the most optimal components to replace in composites for maximum lightweighting of the sprung mass. It was estimated that a composite redesign of these components would result in a mass savings of 57% for intermediate end structures, 47% for body side structures and 51% for roof structures.]]></description>
      <pubDate>Fri, 11 Jun 2021 14:37:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1845857</guid>
    </item>
    <item>
      <title>A method for wayside bogie monitoring based on internal yard running vibration</title>
      <link>https://trid.trb.org/View/1845847</link>
      <description><![CDATA[This paper proposes a non-dismantling functional inspection method for components of the bogie for improved safety and streamlined maintenance. This method uses camera images taken from approximately 2 m away to measure the bogie vibration generated when the vehicles pass over iron plates about 10 mm in thickness and conducts a functional inspection of the bogie components based on changes of their natural frequency. This paper demonstrates the effectiveness of the method by reporting an experiment where some of the bogie components of actual vehicles were replaced and set to different characteristic conditions. It also establishes a simplified and clear dynamic numerical model and theoretically confirms that the measurement results were due to the effect of the replaced component. The potential for efficient maintenance by using the proposed measurement method, analysis method, and numerical model is also presented.]]></description>
      <pubDate>Thu, 10 Jun 2021 09:53:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1845847</guid>
    </item>
    <item>
      <title>Study on the Effect of Bogie Frame Structural Reliability on Rolling Stock Operation Safety</title>
      <link>https://trid.trb.org/View/1756665</link>
      <description><![CDATA[Bogie frame is one of the main load-bearing components of rolling stock, its structural reliability and wheel-rail force interact with each other. By establishing a rolling stock rigid-flexible coupling model, the stress level of the bogie frame in different working conditions is analyzed, the bogie frame stress level changes before and after the structural improvement and the impact on the vehicle operation safety are studied. The results show that after structural reinforcement, the stress level at the connection between the base of the positioning arm and the lower cover plate decreases significantly. With the increase in train running speed, the stress improvement effect decreases gradually. In addition, the derailment coefficient and wheel load reduction rate under the improved frame have no significant change, but the value decreased, which indicates that the improvement of frame structure can improve the train operation safety.]]></description>
      <pubDate>Thu, 25 Mar 2021 09:35:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1756665</guid>
    </item>
    <item>
      <title>Carbody vibrations of high-speed train caused by dynamic unbalance of underframe suspended equipment</title>
      <link>https://trid.trb.org/View/1712074</link>
      <description><![CDATA[The effect of dynamic unbalance of the underframe suspended rotational equipment on the flexible vibrations of the carbody has become a major concern for high-speed trains. It is known from the field tests that the dynamic unbalance has a significant influence on carbody vibrations, especially the local flexible vibration, which leads to a decrease in the passenger ride comfort and may even cause structural damage to the carbody. A vertical mathematic model considering the carbody flexibility and the underframe suspended equipment is first set up, and then a three-dimensional dynamic model for a rigid–flexible coupled vehicle system is established. The effect mechanism of the dynamic unbalance on carbody flexible vibration is extensively studied, and the efficient measures to reduce the carbody flexible vibrations are proposed. The theoretical and simulation models are verified by comparing with a field test conducted on a newly designed high-speed railway. The results show that decreasing the unbalanced mass of the rotational equipment can reduce the carbody vibrations. Moreover, the use of elastic suspension for the underframe equipment can isolate the vibration transmission to the carbody. Both the theory of dynamic vibration absorber and dynamic unbalance should be considered to optimize reasonable suspension parameters, especially the suspension location and the suspension frequency.]]></description>
      <pubDate>Mon, 01 Feb 2021 16:08:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1712074</guid>
    </item>
    <item>
      <title>Car body floor vibration of high-speed railway vehicles and its reduction</title>
      <link>https://trid.trb.org/View/1757170</link>
      <description><![CDATA[An on-site test has been performed to address the problem of feet numbness caused by the floor vibration of high-speed railway vehicles. Analysis of the floor vibration performance indicates that the vibration of the car body chassis transmitted to the floor by the elastic supports is significantly amplified in the frequency range of 20–50 Hz. This overlaps with the frequency range in which human lower extremities are most sensitive, leading to feet numbness. A refined finite element model of the car body, including the floor panels is developed to further study the vibration mechanism of the floor. Results show that due to the inappropriate design of the elastic support stiffness, the deformations of the floor above the bogie centre for several typical modes in the frequency range of 20–50 Hz are significantly amplified. When the excitation frequencies transmitted from the car body chassis were close to the eigenfrequencies of the floor, the local resonance of the floor will occur, which is the root cause of human feet numbness. The dynamic stiffness of the  elastic support is further optimised, and the experimental verification shows that the vibration transmissibility from the car body chassis to the floor in the frequency range of 20–50 Hz has been significantly reduced, and the problem of feet numbness has been solved.]]></description>
      <pubDate>Thu, 31 Dec 2020 13:32:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1757170</guid>
    </item>
    <item>
      <title>Greater Visibility</title>
      <link>https://trid.trb.org/View/1760685</link>
      <description><![CDATA[Advanced technologies are bringing more visibility to critical railcar components and offering the potential for improved rail safety and maintenance. This article examines Railinc’s Component Tracking program, a multi-phase, multi-year initiative to create a process and related technology tools for capturing railcar equipment component data. Manufacturers can register their components in Umler® and these components can then be associated with railroad equipment later. The article explores how the American Association of Railroads (AAR) Technical Service Group's Wheel, Axles, Bearings & Lubrication (WABL) Committee has overseen the implementation and testing of new technologies for rail components.]]></description>
      <pubDate>Wed, 30 Dec 2020 11:53:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1760685</guid>
    </item>
    <item>
      <title>Research on Subhealth Diagnosis Method for Resistance of Urban Rail Transit Door System</title>
      <link>https://trid.trb.org/View/1754754</link>
      <description><![CDATA[The rail vehicle door system is one of the key components of rail vehicles. Its failure rate accounts for more than 30% of vehicle failures. By analyzing early warnings provided by subhealth data from the door system, the efficiency and reliability of their health maintenance can be effectively improved and stable operation of the door system can also be guaranteed. In this paper, early-stage resistance changes in the subhealth state of rail vehicle door systems are considered as the research object. Firstly, the distribution rules for the motor parameters are studied, and the time-domain and normal operating envelope features of the operating motor are extracted. Secondly, subhealth conditions with different resistances are simulated using a test rig, and the experimental data are applied to summarize the rules. According to the subhealth types and the distribution of features, diagnostic rules for subhealth are formulated. To check the possibility of fault diagnosis, a verification using running rail vehicle door system data is carried out in MATLAB. The results reveal that the misdiagnosis rate of resistance subhealth is 0% while the rate of missed diagnoses is 2%. Meanwhile, the diagnostic process based on the established rules is relatively efficient. This method is suitable for application for resistance subhealth diagnosis of urban rail vehicle door systems.]]></description>
      <pubDate>Wed, 23 Dec 2020 12:17:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1754754</guid>
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