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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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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Ultrasonic monitoring of insulated block joints</title>
      <link>https://trid.trb.org/View/1584333</link>
      <description><![CDATA[Insulated block joints are essential components used in railway tracks. They are divided into circuits and are used for train detection and signalling. However, they also represent a weak point in the track system and have a finite life. Condition monitoring of these components for planning preventative maintenance is currently labour intensive, and can be significantly expensive for the rail operator. In this study, insulated block joints were fatigued via shear load, whilst being condition monitored for degradation using a normally incident ultrasonic technique. Tests were also initially performed on lap-joints and shear specimens to further understand the response of the ultrasonic signal to failure of the adhesive layer under controlled conditions. Dynamic reflection coefficients as well as the applied load were recorded in all tests, and results were compared to failure zones on the specimens. The results showed that the ultrasonic technique was able to determine the onset of failure and de-bonding of the adhesive layer in addition to degradation and wear. The technique was also able to highlight differences in performance between two different liners, pultruded glass reinforced polyester resin and a flexible glass fibre sheet, with the latter showing improved resistance. The outcomes of this study have highlighted the viability of condition monitoring insulated block joints using an ultrasonic approach and have provided a basis for a future field trial.]]></description>
      <pubDate>Fri, 22 Feb 2019 17:06:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1584333</guid>
    </item>
    <item>
      <title>Sleeper embedded insulated rail joints for minimising the number of modes of failure</title>
      <link>https://trid.trb.org/View/1529984</link>
      <description><![CDATA[Insulated rail joints (IRJs) identify broken rails and train locations in railway signalling circuitry, which are critical to the rail safety operation. Unfortunately, IRJs exhibit several failure modes due to complex interaction between their components, the load spectra and the support conditions. A novel idea of simplifying the design of the IRJs consists of only two pieces of insulated rails embedded into a concrete sleeper in such a way that the free ends of the rails at the gap attain stiffness commensurate to that of the current designs where the gapped rails are connected with two joint bars (also known as fishplates) one on each side of the rail web with the assembly resting on top of sleepers. The advantage of the new design is that it exhibits stability levels comparable to the current designs with fewer components and hence fewer failure modes. A multi-objective optimisation framework was used for the development of the new design that enables safe passage of train wheels across the gap between the rails embedded in concrete sleepers. Feasibility of the sleeper embedded gapped insulated rails under traffic loading is demonstrated through a dynamic analysis of a rail wheel rolling on top of a selected optimal design from the Pareto front. The deformation components of the rail edge at the gap of the new design are shown to be lower than that of the classical insulated rail joints.]]></description>
      <pubDate>Mon, 13 Aug 2018 22:26:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1529984</guid>
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    <item>
      <title>Experimental modelling of lipping in insulated rail joints and investigation of rail head material improvements</title>
      <link>https://trid.trb.org/View/1406536</link>
      <description><![CDATA[An insulated rail joint is a component used to join two abutting rails while keeping them electrically separated from one another. This allows for the construction of track circuits and train detection within signalling systems. Electrical failure of the joints can be caused by plastic flow of the rail steel over the insulating gap, known as lipping. In this paper, this failure mode has been experimentally modelled using twin-disc testing and indicative conclusions have been formed. It has been found in this testing that the thickness of the endpost does not have an effect on the rate of lipping, however, the endpost and rail material do have an effect. An endpost with a higher compressive strength will perform better and tougher/harder rail steel will also improve performance. The application of a laser clad layer of tougher material on the running surface, however, gave the greatest resistance to lipping.]]></description>
      <pubDate>Fri, 20 May 2016 15:54:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1406536</guid>
    </item>
    <item>
      <title>Finite element analysis of the mechanical behaviour of insulated rail joints due to impact loadings</title>
      <link>https://trid.trb.org/View/1398882</link>
      <description><![CDATA[Insulated rail joints (IRJs) are safety-critical components in the signalling system of rail corridors. They are subjected to dynamic loads generated by heavy rolling-stock/track- system interactions and degrade faster than the other components of the rail track. Degraded IRJs diminish the reliability of the signalling system, thus posing a serious threat to the safety of rail operations. Therefore, there is a pressing need to closely examine the failure mechanisms of the end posts made of insulated material and inserted into the discontinuity in the rail at IRJs with a view to improving their service life, reliability and efficiency. Only a limited literature is available that examines different materials for IRJ end posts, and these primarily focus on contact pressure and contact stress distributions in the vicinity of the end post, disregarding the damage to the rail ends and end post materials. In this paper, a detailed three-dimensional finite element analysis procedure is carried out to quantify plastic deformation and material damage to the end post and railhead materials of IRJs due to a wheel load above that of the shakedown limit of rail steel. A modified Hertzian contact pressure distribution is considered in this simulation. A 5?mm thickness of an end post is considered at the discontinuity in the rail, which is required to form the six-bolt IRJ. Three popular IRJ end post materials are considered in this study: fibreglass, polyhexamethylene adipamide, and polytetrafluoroethylene. A total of 2000 cycles of a 174?kN dynamic wheel load (in pressure format over the wheel/rail contact patch) are applied on the top of the rail’s surface in the vicinity of the IRJ. Equivalent plastic deformations along with vertical and longitudinal plastic strains for unloaded conditions are presented. The strain plots depict damage of end post materials and ratchetting failure of rail ends. The ratchetting failure modes follow the established trend of decay in ratchetting rate in successive wheel load cycles. Comparisons of strain and stress on the railhead surface and in the railhead sub-surface considering all three different end post materials are put forward. Out of the three end post materials, fibreglass is the optimal material considering the ratchetting mode for the damage of the railhead material.]]></description>
      <pubDate>Thu, 28 Apr 2016 14:43:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1398882</guid>
    </item>
    <item>
      <title>Destructive Arcing of Insulated Joints in DC Electrified Railway</title>
      <link>https://trid.trb.org/View/1284026</link>
      <description><![CDATA[Metro-North Railroad (MNR) and Long Island Rail Road (LIRR) have been experiencing excessive destructive arcing from electric multiple unit (EMU) trains passing over the insulated joints (IJs) at various locations in their third rail electrified territory. The destructive arcing has greatly reduced the life-cycle of insulated joints at these locations. The Railroads have undertaken a study of the phenomena to ascertain the cause(s) and develop possible mitigation of the destructive arcing. The study followed a systems engineering approach, analyzing the elements of the traction system, vehicle propulsion circuits, and signaling system that utilize the track running rails as electrical elements of their circuits. The study included research, testing, analysis, and development of possible mitigations for the Railroads to consider going forward to address the problem. This paper will provide background into the problem, a brief discussion of arcing theory, overview of the testing performed, summary of the findings from the testing, and overview of the potential mitigations developed for the railroads to assess in the stage of resolving the problem.]]></description>
      <pubDate>Tue, 24 Dec 2013 13:09:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1284026</guid>
    </item>
    <item>
      <title>Using standard adhesion tests to characterize performance of material system options for insulated rail joints</title>
      <link>https://trid.trb.org/View/1122532</link>
      <description><![CDATA[Insulated joints (IJs) are often required every few kilometres along railway tracks for signal blocks and rail break detection; practical experience has shown that their life is often a fraction of the life of other track elements on some rail lines subjected to high tonnage freight. This article reports findings from a project conducted to study different bond systems consisting of various combinations of adhesives, fibrous insulators, and rail surface treatments that were of potential interest for increasing the service life of IJs for rail applications. The study was performed in parallel with a finite-element analysis and did not focus on testing real IJs but rather on common adhesion test specimens such as the single lap joint and double cantilever beam configurations. The aim of using these specimens was to simulate potential load and environmental conditions on standard test specimens that were less expensive and easier to construct, test, and analyse. The main goal of the project was to compare a number of combinations of potential IJ components through an extensive test programme. The results highlighted several possible combinations that may warrant further study as actual IJ prototypes. In particular, several material combinations involving materials not currently used by IJ vendors had higher overall performances when compared to currently used combinations, although the extension of improved test specimen performance to actual IJ configurations and service conditions may not follow.]]></description>
      <pubDate>Tue, 29 Nov 2011 13:43:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1122532</guid>
    </item>
    <item>
      <title>Evaluation of Premium and Next-generation Insulated Joints in HAL</title>
      <link>https://trid.trb.org/View/1083573</link>
      <description><![CDATA[Bonded insulated joints (IJs) are the backbone of the current railway signal system. The IJs divide the track into blocks of various lengths. Each block has traffic control signals and IJs on both ends. The signal system is used to detect train presence within the block and to control traffic on the railway. Using the present IJ-based signal system, the presence of broken rails can be detected in many circumstances. Warning lights at railroad/highway crossings are controlled using train presence detection circuits and IJs. However, on heavily used coal routes the performance of conventional IJs has been a significant economic and reliability problem due to their relatively short service lives. To increase service life beyond the guaranteed 500 mgt, several premium IJs, which are improved versions of conventional IJs, have been designed and assembled. Many of these prototype premium IJs have exceeded 1,000 mgt and while this triples service life for heavy-axle-load service applications from 10 years ago, it remains far short of the railroads' goal of having IJ service life match that of the surrounding rail. This article looks at more revolutionary changes in design in order to develop next-generation IJs. Both prototype premium and next-generation IJs are described and discussed.]]></description>
      <pubDate>Wed, 15 Dec 2010 08:57:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1083573</guid>
    </item>
    <item>
      <title>Preliminary Results of Prototype Insulated Joint Tests at the Facility for Accelerated Service Test</title>
      <link>https://trid.trb.org/View/917711</link>
      <description><![CDATA[As part of the Association of American Railroads (AAR) Strategic Research Initiatives Program, Transportation Technology Center, Inc. (TTCI), a wholly owned subsidiary of the AAR, in Pueblo, Colorado, is working with the Federal Railroad Administration (FRA), suppliers, and railroad companies to improve the service life of bonded insulated joints (IJs) in a heavy axle load environment at the Facility for Accelerated Service Testing (FAST). Twenty-eight prototype IJs are being tested at FAST. Prototype IJs were installed in-track by TTCI to examine the extent of improvement in IJ performance and service life using improved conventional and miter cut designs. While long-term performance of these joints remains to be determined, preliminary conclusions made are favorable. Component durability: Flexible material in and around the end post area may reduce adhesive cracking. No significant difference in the performance of bolted versus Huck® fasteners was observed. Higher metal flow was observed at the ends of lower hardness rails. Improved foundations and reduced deflections: Wider wood ties, wood frame ties, and closely spaced wood ties appear to have reduced ballast surfacing requirements under IJs. IJ deflections may be reduced by up to 30 percent by doubling the modulus of current joint bars. Higher modulus bars will also increase fatigue strength of joint bars. Reduced impacts: Due to a smoother wheel transition across the end post, miter cut joints imparted 50 percent lower dynamic loads to rail as compared to conventional IJs. These dynamic loads are comparable to open track. A 3/16-inch rail gap for conventional butt joints is optimal for reducing impacts and metal flow. Solid sawn wood ties provide greater damping as compared to composite wood ties and concrete ties with rubber pads. Reduced longitudinal stresses: Miter cut joints have 40 percent higher resistance to longitudinal loads than conventional IJs.]]></description>
      <pubDate>Mon, 24 May 2010 14:08:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/917711</guid>
    </item>
    <item>
      <title>Update of Experiments at the Revenue Service Mega Sites</title>
      <link>https://trid.trb.org/View/904097</link>
      <description><![CDATA[Revenue service testing by Transportation Technology Center, Inc. at the eastern and western mega sites continues to determine the effects of heavy axle loads (HAL) on track infrastructure and to monitor performance of new technologies and designs intended to improve train operation safety and to mitigate detrimental effects of HAL on the track structure. The Federal Railroad Administration and the Association of American Railroads co-sponsor this research. These two mega test sites were established in 2004 and every year a number of experiments are conducted to address various HAL operation issues. Some experiments are long term, taking a few years to complete and may be conducted in phases. This paper is a summary of findings from experiments conducted in 2008 and the first quarter of 2009. These include experiments on premium rails, wide-gap welds (WGW), insulated joints (IJ), rail anchors on concrete ties, plastic ties, elastic fasteners, and bridge approach remedies.]]></description>
      <pubDate>Wed, 04 Nov 2009 17:24:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/904097</guid>
    </item>
    <item>
      <title>Characterizing and Inspecting for Progressive Epoxy Debonding in Bonded Insulated Rail Joints</title>
      <link>https://trid.trb.org/View/881369</link>
      <description><![CDATA[Progressive epoxy debonding is a common factor in many failures of bonded, insulated joints (IJs) in heavy axle load railroad service. This paper describes a study in which IJs with different amounts of debonding were visually inspected and measured and then disassembled. The shape and area of the debonded region for each IJ was quantified and variability between joints recorded. Because of some degree of ambiguity in the visual appearance of the interior surfaces, two different criteria for identifying the boundaries of the debonded region are described and applied. Debonding usually extends farther along the upper and lower portions of the rail–joint bar interface, resulting in a V- or U-shaped debonded region. Additionally, debonding tends to be more extensive on one end of the joint than the other, although it appears that debonding is generally about equal on the field and gage sides. The total debonded area was compared with several linear measurements of damage to the externally visible top edge of the epoxy–insulator layer—the part that is available for inspection in an in-service IJ. There is a strong correlation between the total debonded area in the joint and the total extent of damaged (missing or loose) top insulator edge. The debonded area can be estimated visually, with 80% confidence, to within 12,000 to 28,000 mm², depending on which criteria are used to define the debonded region.]]></description>
      <pubDate>Tue, 19 May 2009 07:48:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/881369</guid>
    </item>
    <item>
      <title>Prediction of Dynamic Train-Track Interaction and Subsequent Material Deterioration in the Presence of Insulated Rail Joints</title>
      <link>https://trid.trb.org/View/806422</link>
      <description><![CDATA[Numerical analysis of high-frequency dynamic train-track interaction is combined with the analysis of material deterioration in terms of rolling contact fatigue (RCF) and plastic deformation to analyze the influence of insulated rail joints.  These joints form local rail irregularities and lead to a local change of dynamic track stiffness.  Dynamic responses at wheel passes are evaluated.  Further, related plastic deformations at the joint and increased RCF impact along a stretch of the track adjacent to the joint are predicted.]]></description>
      <pubDate>Wed, 25 Apr 2007 13:46:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/806422</guid>
    </item>
    <item>
      <title>IMPROVING THE PERFORMANCE OF BONDED INSULATED JOINTS</title>
      <link>https://trid.trb.org/View/750370</link>
      <description><![CDATA[High tonnage rates and increased degradation from higher dynamic loading can create significant economic problems for railroad track. The service life of bonded insulated joints (IJ) on tracks that are heavily used on coal routes, for example, suffers from degradation and is ultimately reduced. Bonded IJ, while allowing for train traffic control and improved safety and track capacity, also leads to an increase in maintenance and service disruptions.  This article discusses research that is examining current degradation modes and the effects that design parameters have on performance. It looks at service life data for a group of IJ that were installed for a signal upgrading project. The data show that higher wheel loads, dynamic loads, longitudinal forces, and traffic density all contribute adversely to service life on a line carrying mostly higher speed intermodal traffic. An analysis of IJ degradation modes can enable railroads and suppliers to develop designs, prototypes, and maintenance procedures that can ultimately improve IJ performance.]]></description>
      <pubDate>Wed, 02 Mar 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/750370</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF GLUED INSULATION JOINT WITH FABRICATED SOLID ADHESIVE COMPOSITE SHEET</title>
      <link>https://trid.trb.org/View/276080</link>
      <description><![CDATA[For improvement of glued insulation joints in long welded rails, a glued joint with fabricated solid adhesive composite sheet has been developed.  This dry type prepreg is made of glass paper soaked in epoxy resin as the matrix. The adhesive strength of this prepreg is above 30 MPa.  A glued joint using this sheet has a tensile strength of 3.0 MN and a small variation coefficient.  (Edited author abstract)]]></description>
      <pubDate>Sat, 28 Aug 2004 04:44:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/276080</guid>
    </item>
    <item>
      <title>NEW METHOD FOR ESTIMATING DURABILITY OF POLYCARBONATE USED IN RAILWAY TRACK</title>
      <link>https://trid.trb.org/View/218301</link>
      <description><![CDATA[The purpose of this study is to develop a method of estimating the practical durability of polycarbonate applied to railway tracks.  Polycarbonate has been widely used as a rail insulating material, but it sometimes deteriorated sooner than expected.  The author tried to estimate the practical durability in the laboratory and developed the C-type method.  By comparing laboratory data obtained by the C-type method with field test results, it is concluded that this method is useful for estimating the practical durability of polycarbonate in railway tracks, and is applicable to other dynamic uses as well as to other kinds of plastics and rubber.]]></description>
      <pubDate>Sat, 30 Nov 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/218301</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF A LONG LIFE INSULATED RAIL JOINT</title>
      <link>https://trid.trb.org/View/216551</link>
      <description><![CDATA[Insulated rail joints used at the end of a track circuit are required to have enough mechanical strength against the train axle load or the thermal pressure of rail, besides the property of electric isolation.  In spite of many studies to improve the mechanical strength of insulated rail joints and to decrease the breakdown of joints that causes traffic interruptions, the results were not fully satisfactory so far.  Recently, JNR constructed the testing installations for insulated rail joints.  With the installations, studies were carried out to extend the life of the built-up type insulated rail joints and an improved joint which has a life more than twice that of present joints was obtained.]]></description>
      <pubDate>Fri, 31 May 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/216551</guid>
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