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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Research in Progress (RIP)</title>
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      <title>Ultrasonic Inspection of Reconditioned Railroad Bearing Components – Year 3</title>
      <link>https://rip.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://rip.trb.org/View/2574196</guid>
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      <title>Effect of Long-Term Inactivity on Railcar Bearing Lubricant and Seal Function</title>
      <link>https://rip.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>
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    <item>
      <title>Comparison of Onboard Condition Monitoring System Mounting Location for Freight 
Railcar Bearing Defect Detection Using Vibration Signatures</title>
      <link>https://rip.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>
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