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    <title>Transport Research International Documentation (TRID)</title>
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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>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Effects of Temperature on Wheel Shelling</title>
      <link>https://trid.trb.org/View/1706468</link>
      <description><![CDATA[In 2014, Transportation Technology Center, Inc. (TTCI) reviewed and summarized published data and the capabilities of twin disk machines that included a unique machine that allows elevated temperature testing. TTCI suggested a methodology for future testing on this thermally controlled twin disk machine. Researchers reviewed existing literature regarding the relationship between temperature and wheel properties such as yield strength, residual stress, and shelling life. Comments are included on historical changes in wheel life, trends in removal causes, and important changes to the wheel operating environment such as the introduction of the Association of American Railroads (AAR) M-976 truck and changes to the AAR brake ratio requirements.]]></description>
      <pubDate>Tue, 19 May 2020 16:39:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1706468</guid>
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      <title>Effect of temperature on the performance of railroad wheels</title>
      <link>https://trid.trb.org/View/1479232</link>
      <description><![CDATA[Sliding and tread brake heating are known to alter microstructures and properties and show causal relationships with shelling and spalling. Temperature can also affect the performance of wheels in other ways: rolling contact forces depend on the size of the contact patch, which is affected by the elastic modulus, which in turn is affected by the tread temperature. Temperature differences from the rim to the remaining portion of the wheel may cause distortions, which may result in unfavorable contact between the wheel and the rail. Cold temperatures affect the fracture toughness and, in the presence of water, may cause wedging, which will accelerate the shelling process. Oxidation within a crack can also cause wedging, resulting in the propagation of thermal cracks. Changes in the residual stress due to brake heating can also affect shakedown. This study considers the many ways of how temperature can affect the performance of the railroad wheel of a freight car. Most of the author’s observations relate to the freight car service in North America and may not be applicable to other types of service in other parts of the world.]]></description>
      <pubDate>Tue, 29 Aug 2017 10:07:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1479232</guid>
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      <title>Wheel Failure is Not an Option</title>
      <link>https://trid.trb.org/View/1143638</link>
      <description><![CDATA[The railroad industry spends close to $1 billion a year replacing bad wheelsets. The article shows a very small but important minority of wheelsets fail in a way that can cause a train accident. According to the Federal Railroad Administration (FRA) safety data, the top two causes of wheel related train accidents are broken rims and tread buildup. To address wheel problems, the Transportation Technology Center, Incorporated (TTCI) is testing improved wheel steels that are designed to resist wheel shelling, and also conducting root cause analysis of broken rim and tread buildup failure modes. Domestic and overseas wheel manufacturers produce high performance wheel steels that have the potential to improve wheel life by offering increased resistance to shelling. The article discusses the testing, benefits, and results of eight types of these high performance wheels. The FRA has teamed with the American Association of Railroads (AAR) to co-fund research to better understand the conditions necessary to produce broken rims and tread buildup.]]></description>
      <pubDate>Tue, 24 Jul 2012 09:11:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1143638</guid>
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      <title>Measurement of Wheel/Rail Load Environment in Relation to Rolling Contact Fatigue</title>
      <link>https://trid.trb.org/View/1122527</link>
      <description><![CDATA[Wheel shelling is the cause of a large portion of high impact wheels. The impact loads produced by shelled wheels can have a damaging effect on track components and rolling stock components such as roller bearings. Shelling is the result of accumulated rolling contact fatigue (RCF) on the wheel tread surface. To investigate the specific conditions in which RCF occurs, wheel load environment data was collected from a car with three-piece trucks running in revenue service. This data was analyzed in order to assess the predicted wheel RCF through the use of shakedown theory. An inspection team was dispatched to several track sites to record relevant information including a visual assessment of rail RCF, rail transverse profile, rail age, and friction conditions. Track inspections were conducted at locations where RCF was predicted and at nearby locations with similar curvature where RCF was not predicted. Conclusions from this work are the following: (1) The curve unbalance condition, which is a combination of curvature, track superelevation, and train speed, is an important factor in RCF. (2) Wheel/rail coefficient of friction in curves can be a factor in RCF. (3) Rail profile and track condition were not found to be major factors in this analysis. (4) Observed rail RCF condition correlated reasonably well with predictions when considering extenuating factors such as rail age and curve unbalance conditions. (5) Confidence was increased in previous simulation results involving three-piece trucks due to good correlation with the results of the current work. The simulation results suggest that the use of AAR approved M-976 trucks should reduce RCF. This work was funded by the Federal Railroad Administration (FRA) and the Wheel Defect Prevention Research Consortium (WDPRC), a group that includes railroads, private car owners, and industry suppliers.]]></description>
      <pubDate>Wed, 16 Nov 2011 14:51:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1122527</guid>
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      <title>Crack Initiation in Railway Wheels Resulting From Rolling Contacts</title>
      <link>https://trid.trb.org/View/1122549</link>
      <description><![CDATA[Classic shelling of a railway wheel begins with crack initiation resulting from wheel rail interactions. This investigation shows the complex relationships that occur between contact stress, cold work, residual stresses, and temperatures from brake heating and nonmetallic inclusion types which can lead to the formation of shelling cracks. The authors investigation also includes an explanation of how these interactions affect mechanical properties such as yield strength, elastic modulus, and ductility. In turn, mechanical property changes also affect how cold work and its associated residual stresses develop under cyclic loading. Destructive testing and Finite Element Analyses were used in support of this work.]]></description>
      <pubDate>Wed, 16 Nov 2011 14:51:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1122549</guid>
    </item>
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      <title>In Search of Longer Wheel Life</title>
      <link>https://trid.trb.org/View/919940</link>
      <description><![CDATA[This article describes the use of innovative railroad wheel steels used on Sweden’s Malmbanan iron ore line.  These steels combine good ductility and cyclic yield strength, resulting in increased resistance to rolling contact fatigue (RCF) and a significantly longer shelf life than conventional steels.  The author, an employee of the Italian wheel supplier Lucchini RS, describes that company’s research into casting, forging, tool steels, and rolling stocks materials, then explores RCF wheel failures.  RCF wheel failures can be broadly classified into two types: surface-initiated cracks or spalling, caused by ratcheting or thermal loading, and subsurface-initiated cracks or shelling, caused by Hertzian loads.  Additional topics covered include costly remedies to these problems, the goal of developing better steel grades, new criteria used for comparing these novel materials, and testing conditions used for the wheels.  Lucchini RS developed a steel grade, Micralos, that is a tempered martensitic-bainitic low alloy material with a lower carbon content than the Class C+ grades.  The author concludes by noting that Lucchini RS is now working on an improved version of the Microlos steel grade, with mechanical characteristics designed to improve further its wear resistance to all other RCF phenomena.]]></description>
      <pubDate>Mon, 21 Jun 2010 07:06:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/919940</guid>
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      <title>FATIGUE CRACK GROWTH UNDER MIXED LOADING OF TENSILE AND IN-PLANE SHEAR MODES</title>
      <link>https://trid.trb.org/View/646463</link>
      <description><![CDATA[A method to simulate rolling contact conditions with an in-plane bi- axial fatigue machine has been developed to observe the propagation of fatigue cracks under mixed loading of tensile and in-plane shear modes. The experiments used simplified cycles applied to the analysis of rolling contact fatigue cracks, including the effect of fluid trapped inside the cracks. Last square regression analysis enabled growth rate laws to be obtained in terms of the effective stress intensity factor range.]]></description>
      <pubDate>Wed, 02 Jul 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/646463</guid>
    </item>
    <item>
      <title>IF THE SHOE FITS : TWO SUPPLIERS MAINTAIN THAT THEIR HIGH-FRICTION COMPOSITION BRAKE SHOES CAN REDUCE RAILROADS' WHEEL SHELLING, SPALLING PROBLEMS</title>
      <link>https://trid.trb.org/View/727324</link>
      <description><![CDATA[As ton miles increase and wheels are made to be lighter, problems with wheel damage rise. New high-composition brake shoes promise to reduce shelling and spalling on wheels, the two most common types of damage from prolonged braking on heavily loaded cars. The Cobra TG TreadGuard is a high-friction composition brake shoe. Another model is the high- friction Sintered Brake Shoe. Both models include a function of cleaning wheels of defects created when brakes are applied. Tests show they cut the need to replace wheels significantly, but industry is balking at their high initial cost. Individual railroads are also skeptical that test results from other lines will be duplicated under their unique operating conditions. The two manufacturers are doing more test, including adding featured like a lubricant system to cut fuel consumption.]]></description>
      <pubDate>Thu, 31 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/727324</guid>
    </item>
    <item>
      <title>OPTIMIZING WHEEL, RAIL PROFILES</title>
      <link>https://trid.trb.org/View/506075</link>
      <description><![CDATA[Vehicle/track interaction and the maintenance of the wheel/track interface have gained increasing attention during the recent years, as experience has shown that an optimized wheel/rail interface is one of the most powerful tools available to railway engineers, offering the potential to save millions of dollars spent on wheel, rail, and other component replacement costs.  While the specifics of a well balanced wheel/rail interface will differ from one system to another, the end result is the same.  An optimized wheel/rail interface can control a range of problems, including rolling contact fatigue, wheel shelling, rail fatigue defects, corrugation, wheel/rail noise, excessive rail-gauge-face/wheel-flange wear, wheelset hunting and more.]]></description>
      <pubDate>Fri, 06 Aug 1999 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/506075</guid>
    </item>
    <item>
      <title>PROFILE RAIL GRINDING OFFERS EVEN MORE ON CLOSED-LOOP SYSTEMS</title>
      <link>https://trid.trb.org/View/500705</link>
      <description><![CDATA[The benefits of rail profile grinding have been evident on Class I and other interchange railroads for several years.  Rail grinding and wheel maintenance programs can control problems such as rail corrugation, shelling and fatigue, excessive rail gauge/wheel flange wear, wheel shelling, wheelset hunting, noise and other problems on these types of railroads.  This article examines the dividends rail profile grinding has shown on closed loop, captive fleet freight and transit systems which offer the potential for greater control and finer tuning of the wheel/rail interface.]]></description>
      <pubDate>Wed, 05 May 1999 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/500705</guid>
    </item>
    <item>
      <title>THE EFFECT OF PREVENTIVE GRINDING ON RAIL SURFACE SHELLINGS</title>
      <link>https://trid.trb.org/View/541036</link>
      <description><![CDATA[Rail surface defects called shellings or squats (referred to here as surface shellings) are a kind of rolling contact fatigue defect causing considerable maintenance cost including rail renewal not only on Shinkansen lines but also on narrow gauge lines.  Preventive grinding of rail head surface is currently most reliable and effective as a measure to reduce the occurrence of surface shellings.  However, since the effect of the preventive grinding is not made clear enough, it is of great interest to obtain the optimal grinding period and grinding amount (thickness from rail surface). In this paper the effect of the preventive grinding for Shinkansen rails is discussed on the basis of experimental results using a large rolling disc machine.]]></description>
      <pubDate>Wed, 18 Nov 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541036</guid>
    </item>
    <item>
      <title>FLAT-BOTTOM RAIL DEFECTS</title>
      <link>https://trid.trb.org/View/6565</link>
      <description><![CDATA[In 1944, 38,708 transverse fissure failures were reported, of which 31,781 were discovered in advance of actual failures by patrolling detector cars, and 6,927 were in rails that broke in the track, in certain cases with disastrous results. The use of flat-bottom rails in Great Britain will increase the need to control the cooling process during formation of the rails. The British medium manganese rail is less susceptible to fissure failure due to its lesser carbon content, 0.6 percent carbon in British rails compared to 0.7 to 0.8 percent in U.S. Rails. In the U.S. a troublesome defect is the shelling or flaking of rails on the gauge corner of the head.  This problem is prevalent on the high rail of curves where traffic conditions are severe.  No direct connection has been found between the chemical composition of rails and their susceptibility to shelling, except in so far as the hardness of the steel is affected; heat-treated rails and rails containing 3 percent of chromium have given better results than rails of standard composition.  Water quenching can produce weeping cracks in steel.  Steel with Brinell hardness after end quenching in the range 360 to 375 were not susceptible to weeping cracks.  There is a continuing need for a fishplate steel of reduced notch sensitivity. High manganese alloy fishplates have given good results, but are costly.]]></description>
      <pubDate>Sun, 04 Dec 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/6565</guid>
    </item>
    <item>
      <title>TRACK MAINTENANCE AND HIGH CAPACITY TRUCKS</title>
      <link>https://trid.trb.org/View/6748</link>
      <description><![CDATA[The high capacity truck from the maintenance of way standpoint is the means by which the increased gross weight of the large modern freight car is transmitted to the track, roadbed, bridges, trestles, viaducts and culverts, over which it must pass.  As such, its design, dimensions and position are of vital concern to those responsible for the satisfactory operating condition of the railroad.  Stress in rails and joint bars, track deflection, maximum load on ties and effect on undergrade bridges require specific consideration in determining whether or not a car can be accepted for movement; and if so whether it will be free-running or whether it will be restricted as to speed and routing.  An immediate concern in relation to high capacity car trucks is the anticipated increase in shelling rail failures due to increased bearing pressure.  Shelling rail failures are the result of the plastic flow of metal from the middle portion of the head toward the guage corner under high shearing stresses produced by intense wheel loads eventually starting a horizontal crack.  The Joint Committee on Relation between Track and Equipment has recommended maximum axle loads of 52,800 pounds on 33 inch wheels, 58,400 pounds on 36 inch wheels, and 62,400 pounds on 38 inch diameter wheels.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/6748</guid>
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    <item>
      <title>THE PRINCIPAL RAIL DEFECTS, INTERIM REPORT NO. 3 (CHAPTERS I-IV)</title>
      <link>https://trid.trb.org/View/4189</link>
      <description><![CDATA[A listing of principal rail defects which includes the description, causes, consequences and remedies for each. Those included are: vertical longitudinal splitting, laps, shelling of heattreated rails, gauge corner shelling, star cracking of fish bolt holes, progressive transverse cracking in rail heads, horizontal cracking of rail head and transverse fractures at longitudinal fissures.  Included at the end of each unit are a number of photographs of each flaw.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/4189</guid>
    </item>
    <item>
      <title>THE EFFECT OF THE RATIO OF WHEEL DIAMETER TO WHEEL LOAD ON EXTENT OF RAIL DAMAGE</title>
      <link>https://trid.trb.org/View/5023</link>
      <description><![CDATA[This is a report of progress on studies of pressure as affected by the area of contact between wheel and rail.  One phase of this investigation involves the conduct of rolling load tests of rails subjected to wheels of various diameters and loads.  To summarize, a depth hardness survey on a 112-lb rail removed from service after approximately 12,000,000 tons of traffic shows the maximum hardness to be at a depth of approximately 0.04 in. at a distance of 1-3/6 in. from the center of the head toward the gage side, the maximum hardness being Rockwell C 34.6.  Tests on a full section 131-lb rail under a 75,000-lb load after 1,333,000 cycles (100,000,000 tons) of testing are as follows:  For the 33 in. wheel--a hardness of Rc 15 on the tread and a maximum of Rc 32 at a depth of 0.15 in.; for the 50 in. wheel--a hardness on the tread of Rc 23 and a maximum hardness of Rc 27.4 at a depth of 0.10 in.  Using "mutilated" head specimens and a 50-in. wheel it was found that a 58,000-lb load could be carried for 100,000,000 tons, but that a 63,000-lb load would break down the rail tread after 15-45 million tons.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/5023</guid>
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