<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>TRB Publications Index</title><link>http://pubsindex.trb.org/</link><atom:link href="http://pubsindex.trb.org/common/TRIS Suite/feeds/rss.aspx?tc=NN%3AFmung" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2015. 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>TRB Publications Index</title><url>http://pubsindex.trb.org/Images/PageHeader-wTitle.png</url><link>http://pubsindex.trb.org/</link></image><item><title>Design of Rail Variable Cross Section Grinding Profile Based on NURBS Surface</title><link>http://pubsindex.trb.org/view/2705421</link><description><![CDATA[To eliminate the abnormal wear and shaking caused by the standard grinding method in curved rails, and improve the matching performance and passing ability, a Non-Uniform Rational B-Spline (NURBS) -based design optimization method is proposed in this paper, which is for the variable cross section grinding profile design of curved rails. Compared with the standard rail cross section profile, the effective wheel–rail contact length of the optimized curved section increases. The increases in the wheel–rail contact density of the gently curved section, the gently rounded point, and the rounded curved section are 161.08%, 68.57%, and 271.60%, respectively. Therefore, the wheel–rail contact relationship and the wheel–rail matching performance are significantly improved. The abnormal wear problem caused by the wheel–rail matching performance is reduced. In addition, compared with the standard grinding profile, the maximum reductions in the derailment coefficient, rate of wheel load reduction, wheel–rail transverse force, wheel–rail vertical force, wheel offset angle, and maximum wear index of the optimized designed profile in the curved section are 9.23%, 14.72%, 11.39%, 9.76%, 6.03%, and 12.03%, respectively. Therefore, the dynamic performance is significantly improved. Furthermore, the trains’ curve-passing ability improved, and the shaking-car phenomenon was suppressed. Finally, when the optimized rail grinding profile is adopted, the reduction in the rail grinding removal amount for the transition curve section, slow circular point, and circular curve section reaches 43.41%, 43.39%, and 61.94%, respectively. Therefore, the lifespan of the rail in the curve section is prolonged.]]></description><pubDate>Tue, 26 May 2026 09:44:22 GMT</pubDate><guid>http://pubsindex.trb.org/view/2705421</guid></item><item><title>Multiobjective Optimization of the Worn Turnout Rail Profile Driven by a Hybrid Intelligent Algorithm</title><link>http://pubsindex.trb.org/view/2606446</link><description><![CDATA[When high-speed trains pass through worn turnouts, the severe wear of the rails often leads to the carbody lateral acceleration (CLA) exceeding the standard. However, traditional rail grinding methods that focus on restoring the new rail profile are problematic for effectively addressing this issue. This study collects data on worn wheels and rails and uses nonuniform rational B-spline curves to accurately fit the worn rail profiles. By integrating the vehicle-turnout coupled dynamics model with the back propagation and nondominated sorting genetic algorithm III hybrid intelligent algorithm, multiobjective optimization of the rail profiles is carried out. While maintaining a good wheel–rail contact interaction, the grinding amount is reduced. The research reveals that the differential wear of the rails at different positions causes surface irregularities, leading to significant fluctuations in the nominal equivalent conicity, which is a key factor contributing to the excessive CLA. Simulation analysis shows that compared with the new profile and the representative worn profile, when a vehicle equipped with worn wheels runs on the optimized profile, the carbody acceleration, frame acceleration, wheel–rail forces, derailment coefficients, wear indices, and fatigue indices are all reduced. In the field application, after 10?months of monitoring the optimized profile, the CLA does not exceed the standard. The deviation between the measured profile and the optimized profile meets the acceptance criteria, and the grinding efficiency is improved. In conclusion, the optimized profile effectively solves the problem of excessive CLA, enhancing the stability and safety of high-speed train operations.]]></description><pubDate>Wed, 08 Oct 2025 09:29:42 GMT</pubDate><guid>http://pubsindex.trb.org/view/2606446</guid></item><item><title>Research on the Experimental Control of Abnormal Vibration on High-Speed Lines</title><link>http://pubsindex.trb.org/view/2559580</link><description><![CDATA[With the continuous increase of operational mileage of high-speed trains in China, wheel–rail wear and various dynamics problems are gradually being exposed. Abnormal vibration in the carbody appeared during operation. To solve this problem, the rail profiles, wheel profiles, and vehicle vibration acceleration were measured. A coupled rigid–flexible dynamic model of high-speed trains has been established. Through the analysis of the dynamic response, the causes of the abnormal vibrations of electric multiple units were studied. The results show that the equivalent conicity is 0.477 when the wear mileage is 100,000?km, and the 6–8?Hz bogie hunting frequency transmission to the carbody is the main factor that produces carbody shaking. Wheel re-profiling, improving line quality, and rail grinding are proposed to solve the problem of abnormal carbody shaking. Wheel re-profiling can effectively reduce the equivalent conicity. The personalized profile grinding method can improve the wheel/rail contact relationship. The bogie hunting frequency should be avoided to prevent resonance with the carbody’s first-order elastic mode. The machine tamping control also improves the stiffness under the rail and improves line geometric irregularity, combined with the function of the rail grinding, further eliminating carbody shaking.]]></description><pubDate>Sun, 01 Jun 2025 18:15:43 GMT</pubDate><guid>http://pubsindex.trb.org/view/2559580</guid></item><item><title>Design Method of Worn Rail Grinding Profile for the Curve Section</title><link>http://pubsindex.trb.org/view/2107942</link><description><![CDATA[The grinding profile directly affects the wheel–rail contact relationship, so it is necessary to study the design method of rail grinding profiles for the curve section. Based on the Frechet distance method, the selection method of representative profile for worn rails was established. Based on the non-uniform rational B-spline theory, the description model of the rail profile was constructed. The reduction of rail grinding material removed and improvement of wheel–rail contact geometry were taken as the optimization objectives, and the multi-objective function of the grinding profile of the outer rail in the transition curve and circular curve section was established. The optimized design results show that compared with the measured grinding profile in the field, the rail grinding amount is reduced by 80.1% and 11.3% by using grinding profiles designed for the transition curve section and the circular curve section, respectively, and the distribution of wheel–rail contact points is more uniform. The dynamic indexes under different velocities and different radii are significantly reduced, and the curve passing performance is improved. The area of wheel–rail contact spot changes uniformly with the lateral displacement of the wheelset, and the maximum von Mises stress is improved obviously. The wear index and surface fatigue index decreased significantly. The optimized grinding profile can effectively extend the maintenance cycle and service life of the curved rail.]]></description><pubDate>Thu, 02 Feb 2023 14:51:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/2107942</guid></item><item><title>Light Rail Vehicle Noise: Evaluation of Rail Roughness and Noise from Wheel–Rail Interface</title><link>http://pubsindex.trb.org/view/1393680</link><description><![CDATA[Sound Transit opened its first light rail line, the Central Link, in Seattle, Washington, in 2009. There were many community noise issues immediately after the line went into revenue service that were generally attributed to poor quality rail grinding when the initial mill scale grinding was performed. As a result of that experience, Sound Transit has been cautious when predicting noise and designing noise mitigation for new alignments. Future alignments include the University, Northgate, and Lynnwood Links to the north; the Federal Way and South 200th Links to the south; and the East Link to the east. Over the next 15 years, the system will be expanded from 16 mi to more than 50 mi. The detailed noise data collected as part of the final design of East Link suggest that measures could be taken to reduce the need for substantial noise mitigation on future Sound Transit extensions. This paper summarizes the measurements and key observations from that noise study. One key observation suggests that through implementing acoustic rail grinding and maintaining the current wheel truing program, there is potential for minimizing the amount of sound walls required to achieve community noise goals. The results also suggest that through a detailed, information-based investigation, reference noise levels used to determine the need for noise mitigation could be reduced by approximately 4 dB. However, the results of this study, combined with experience from rail roughness studies in general, suggest that achieving a true acoustic rail grinding that leaves no artifacts is not straightforward, because it requires careful monitoring by the rail grinder operator as well as quality control measurements by the grinding company or the transit system.]]></description><pubDate>Tue, 05 Apr 2016 12:30:32 GMT</pubDate><guid>http://pubsindex.trb.org/view/1393680</guid></item><item><title>An Asymmetrical Grinding Method for Rails of High-Speed Turnout Switch</title><link>http://pubsindex.trb.org/view/1392600</link><description><![CDATA[The height difference between switch rail and stock rail at switch of high-speed turnout may cause noticeable hunting motion of wheel-set. The hunting motion of wheel-set may degrade lateral stability of carbody and produce lateral impact on rails greatly. Based on the theory of asymmetrical rail grinding, the paper presented a method to enlarge the rolling radius difference between the two wheels of a wheel-set by grinding the gauge side of straight stock rail and the field side of curved stock rail, to improve the ability of wheel-set to back to the line center, and the final purpose is to improve the hunting motion of wheel-set traveling at the switch of high-speed turnout in the main line. The wheel/rail (w/r) contact status and the dynamic characteristics of vehicle-turnout coupling system before and after asymmetrical rail grinding were compared and analyzed using numerical calculation and theoretical simulation. The results show that the asymmetrical rail grinding method is advantageous in improving the hunting motion of wheel-set and the lateral stability of vehicle when travelling at the switch of high-speed turnout in the main line, however, it is disadvantageous in worsening the rail defects and wear within the range of wheel load transition.]]></description><pubDate>Mon, 04 Apr 2016 10:16:08 GMT</pubDate><guid>http://pubsindex.trb.org/view/1392600</guid></item><item><title>TECHNIQUES FOR CONTROLLING RAIL CORRUGATION</title><link>http://pubsindex.trb.org/view/271178</link><description><![CDATA[Corrugation on low rails in curved track is a common and significant problem on North American railways. Research findings on probable causes are described and practical methods of keeping this problem under control are suggested. The role of wheel and rail contact stresses in the plastic deformation of rail surface, a necessary condition for corrugation development, is examined, and the use of high-strength steel and rail profile grinding to control rail corrugation through reducing or preventing rail surface plastic deformation is discussed. Results of recent field trials of rail corrugation control using a rail profile grinding technique are presented.]]></description><pubDate>Sun, 31 Jul 1988 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/271178</guid></item></channel></rss>