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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>
    <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>ANALYSIS OF TRACK SHIFT UNDER HIGH-SPEED VEHICLE-TRACK INTERACTION. SAFETY OF HIGH-SPEED GROUND TRANSPORTATION SYSTEMS</title>
      <link>https://trid.trb.org/View/573986</link>
      <description><![CDATA[This report describes analysis tools to predict shift under high-speed vehicle-track interaction.  The analysis approach is based on two fundamental models developed (as part of this research); the first model computes the track lateral residual deflections under vehicle passage, whereas the second determines the lateral dynamic loads generated as the vehicle negotiates misaligned tangent or curved tracks.  The track, residual deflection model takes the loads from the vehicle dynamic model as inputs and is based on a quasi-static beam theory and an appropriate trilinear constitutive representation for the tie-ballast lateral resistance under the wheel vertical loads. The vehicle dynamic model is based on a multibody simulation which maintains a wheel-rail rolling contact connection with a complaint track representation.  Computer codes (OMNISIM) for track residual deflection and for vehicle multibody simulation with complaint track element have been developed to facilitate parametric study.  OMNISIM, which has been developed through extensive modifications of previous programs (which do not permit a complaint track element) is shown to have several advantages including accuracy in the evaluation of loads and wheel climb predictions.]]></description>
      <pubDate>Tue, 18 Nov 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/573986</guid>
    </item>
    <item>
      <title>ANALYSIS OF CROSSTIE TRACK IN LATERAL PLANE USING NEW TRACK EQUATIONS</title>
      <link>https://trid.trb.org/View/483445</link>
      <description><![CDATA[Analysis of a crosstie railroad track in the lateral plane is usually based on the theory of a beam on an elastic foundation in which bending rigidity of the track structure is assumed to be twice the rigidity of a single rail.  The ballast resistance is modeled using a linear Winkler foundation with modulus k. Traditional analysis does not consider the contribution of the ties and rail-tie fasteners to the bending stiffness of the track and the nonlinearity of the ballast resistance.  The authors of this paper present an analysis of an infinitely long crosstie track subject to a concentrated lateral load.  The analysis is based on new track equations, and the equations explicitly consider the contribution of the rails and rail-tie fasteners to the bending stiffness of the track.  A bilinear approximation is assumed in representing the lateral resistance due to the ballast.  A closed-form solution for track deflection is derived using the new equations, for displacements in the linear regime. A closed-form solution is derived for the nonlinear response using a simplified set of track equations.  The authors also present a method for determining the model track parameters that is based on a least-squares fit to experimental load-deflection data.  Results indicate that the analytical solution accurately predicts the measured data for the entire range of loads and over the full length of track.]]></description>
      <pubDate>Mon, 02 Jun 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/483445</guid>
    </item>
    <item>
      <title>TRACK MODULUS MEASUREMENTS ON A HEAVY HAUL LINE</title>
      <link>https://trid.trb.org/View/425391</link>
      <description><![CDATA[Measurement of track deflection under vertical load is proposed as a means of assessing the structural condition of the track. The results can be presented in the form of (a) vertical rail deflection under a specified load or change in load, (b) track stiffness defined as the ratio of change to load to change in rail deflection, or (c) track (foundation) modulus as defined by the beam-on-elastic-foundation model.  Examples of such data are given from tests on a heavy haul line.  The single vertical load point method was used.  Characteristics of the load-deflection relationships are shown.  The curves were subdivided into two parts.  The first part is the seating deflection, which indicates the voids under the rails and ties.  The second part is the contact deflection, a function of the substructure layer stiffness properties.  Deflection basins were also measured and compared with basins calculated using a computer model.  The study showed that continuous deflection profiles along the track are useful in characterizing the track support conditions and their variations.]]></description>
      <pubDate>Mon, 22 May 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/425391</guid>
    </item>
    <item>
      <title>TRACK MODULUS MEASUREMENTS AT THE PUEBLO SOFT SUBGRADE SITE</title>
      <link>https://trid.trb.org/View/425389</link>
      <description><![CDATA[At the Pueblo test facility a clay subgrade layer 1.5 m (5 ft) thick was installed to provide a low modulus track.  The performance and maintenance requirements of this track under accumulated traffic (with a 170-kN or 39-kip wheel load) were compared with those of an adjacent track section with natural stiff subgrade.  In this way the effect of substructure condition on track performance was distinguished.  It was determined that the low modulus track produced a more variable support condition than did the stiffer track.  Larger variation in support provided more differential settlement and, therefore, required more smoothing maintenance.  Track deflection under load provides information regarding substructure support and related track maintenance needs.  Three ways of characterizing the load-deflection characteristics of track were considered: track deflection, track stiffness, and track modulus.  The results of these measurements are shown and compared, and the implications of using each are discussed.  Whichever technique is used, a system that can take measurements on a continuous basis is recommended to determine the support characteristics along the track.  Such a system could be used to identify those sections requiring differing amounts of maintenance and those that may need rehabilitation to increase the modulus to an acceptable level.]]></description>
      <pubDate>Mon, 22 May 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/425389</guid>
    </item>
    <item>
      <title>ON THE MEASUREMENT AND CALCULATION OF VERTICAL TRACK MODULUS</title>
      <link>https://trid.trb.org/View/159596</link>
      <description><![CDATA[This paper presents the results of a series of tests and analyses directed towards the characterization of the track structure under vertical loads.  It also presents and evaluates different analytical techniques for the calculation of the vertical track modulus.  In a series of tests at the Association of American Railroads's Track Structures Dynamic Test Facility, the response of the track was obtained by monitoring track deflection under increasing vertical loads.  This load and deflection data was then used to calculate vertical track modulus, track stiffness and track compliance.  Three widely used techniques were utilized to calculate the vertical modulus.  The results of the tests indicate that the modulus of the track is related to the level of loading; thus identical track can give different modulus values for different load levels.  Of the three different techniques used to calculate track modulus, the beam-on-elastic-foundation technique was found to be the most applicable to field measurements since it requires a minimum number of track deflection values.]]></description>
      <pubDate>Tue, 16 Sep 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/159596</guid>
    </item>
    <item>
      <title>PRELIMINARY FIELD EVALUATION OF A TRACK STRENGTH TEST VEHICLE</title>
      <link>https://trid.trb.org/View/151265</link>
      <description><![CDATA[This report presents the results of a preliminary field evaluation of the Track Strength Test Vehicle, the Decarotor.  The objectives of this test series are to define the capabilities and limitations of the test vehicle and to examine the capabilities of the system to measure track strength and identify "weak" track of yard quality.  The test results indicated that the system could successfully and repeatedly identify weaknesses in the track section such as poor joints or groups of ties in "poor" condition.  It was further noted that these tests could be performed at increasing speeds and without significant damage to the track structure.]]></description>
      <pubDate>Wed, 27 Aug 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/151265</guid>
    </item>
    <item>
      <title>DYNAMIC MODELS OF A RAILROAD TRACK SYSTEM</title>
      <link>https://trid.trb.org/View/153458</link>
      <description><![CDATA[A continuum model with microstructure is presented for a railroad track system.  The track is represented as a laminated structure with two layers continuously supported by springs and dampers.  Solutions for deflections of the track system subjected to a moving wheel load are obtained in a close form using complex Fourier transforms for both damped and undamped foundations.  Comparisons are made with the results obtained from quasi-static models of the track, which simulate the track as a single equivalent homogeneous beam on an elastic foundation with an effective modulus suggested by W. Voigt.  Results of the model are compared with experimental data in limiting cases.  Critical velocities are calculated for the track system with conventional rails.  The influence of foundation modulus on critical velocity is analyzed in some detail.  Critical velocities are also computed for an equivalent homogeneous track system using equations advanced by A.D. Kerr for a beam.]]></description>
      <pubDate>Mon, 09 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/153458</guid>
    </item>
    <item>
      <title>TRACK STRENGTH CHARACTERIZATION PROGRAM: AN OVERVIEW</title>
      <link>https://trid.trb.org/View/147211</link>
      <description><![CDATA[This paper summarizes the background, accomplishments and scheduled test activities of the Track Strength Characterization program.  Recent data from laboratory tests on a track section at the AAR's Track Structures Dynamic Test Facility and pilot studies of field measurement facilities are reviewed.  Details of scheduled field characterization tests are outlined and the design of a field test vehicle reviewed.]]></description>
      <pubDate>Tue, 15 Jan 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/147211</guid>
    </item>
    <item>
      <title>IMPROVED STRESS ANALYSIS FOR CROSS-TIE TRACKS</title>
      <link>https://trid.trb.org/View/146403</link>
      <description><![CDATA[Presently, the dominant method for calculating rail stresses and rail-tie contact forces is based on the model of a beam on a Winkler base.  One shortcoming of this analysis is that it neglects the effect of the moments that the ties exert on the rails when the rails deflect in the vertical plane.  The paper presents an improved analysis of this problem.  It also suggests a simple method for the determination of the track parameters that enter the analysis and demonstrates its use on actual track test data.  Paper concludes with a comparison of analytical and track test results.]]></description>
      <pubDate>Wed, 19 Dec 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/146403</guid>
    </item>
    <item>
      <title>AN IMPROVED ANALYSIS OF RAIL STRESSES AND RAIL-TIE CONTACT FORCES, FOR A CROSS-TIE TRACK</title>
      <link>https://trid.trb.org/View/89203</link>
      <description><![CDATA[Presently, the dominant method for calculating rail stresses and rail-tie contact forces is based on the model of a beam on a Winkler base. One shortcoming of this analysis is that it neglects the effect of the moments which the ties exert on the rails, since when the rails deflect in the vertical plane the cross-ties in addition to displacing vertically also rotate about their axes and the ballast resists these rotations. The paper presents an improved analysis of this problem. It also suggests a simple method for the determination of the track parameters which enter the analysis and demonstrates its use on actual track test data. Paper concludes with a comparison of analytical and track test data, in order to establish the accuracy of the proposed analysis.]]></description>
      <pubDate>Wed, 17 Oct 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/89203</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF MULTILAYER ANALYSIS MODEL FOR TIE-BALLAST TRACK STRUCTURES</title>
      <link>https://trid.trb.org/View/141398</link>
      <description><![CDATA[A multilayer analysis model for tie-ballast track structures has been developed.  The model includes the effects of rail bending, rail-fastener stiffness, tie bending, variable ballast and subgrade material types, and variable tie spacing and ballast depth.  The results predicted by using the model are compared with experimental results and excellent agreement is shown.  The model offers the advantages of simplicity of use and reduced computer run time when compared with the finite-element codes currently used.]]></description>
      <pubDate>Sat, 29 Sep 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/141398</guid>
    </item>
    <item>
      <title>MATHEMATICAL MODELS FOR TRACK STRUCTURES</title>
      <link>https://trid.trb.org/View/88098</link>
      <description><![CDATA[Fifteen mathematical models are developed here to predict stresses and deflections due to vertical and lateral wheel loads in track structures for establishing design and maintenance procedures.  The modelling approach utilizes a series of models to simulate various aspects of track structures.  Several models are developed for the same objective with simpler models for preliminary studies and more complex and versatile models for more comprehensive studies.  The models are evaluated with regard to capabilities and agreements with published test data.  Model predictions agree well with test data for cases in which test data are complete for purposes of model validation. Such is the case for models predicting rail stresses and deflections.  Tie and ballast-subgrade models cannot be properly validated for lack of complete test data.  No test data is available for validation of rail joint and fastener simulations and models incorporating track irregularities and non-linear response characteristics.  Test data generated under a carefully controlled environment are required to validate the models.  A limited parameter study is conducted with each of the models.  The parameter investigations are meant to be illustrative rather than comprehensive.  It is suggested that additional parameter investigation be undertaken with emphasis on track design parameters.]]></description>
      <pubDate>Tue, 31 Jul 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/88098</guid>
    </item>
    <item>
      <title>INFLUENCE OF TRACK FORM AND TRAIN OPERATING LOAD ON TRACK-HEIGHT CHANGE</title>
      <link>https://trid.trb.org/View/86005</link>
      <description><![CDATA[The main reason for the change in the height of the ballasted track under the train load is the altered seating of the ties on the ballast.  The track transmits vertical forces which cause granular ballast movement and a sagging of the track.  Depending on the condition of the line, the calculated mean ballast compression under a 20-tonne axle is between 0.10 and 0.14 N/sq mm.  Taking account of all load-increasing influences, the maximum can be up to two to three times the mean value.  For permanent-way practice, knowledge of the height-changing effect of various ballast compression values caused by different track and bed forms is of special importance.  Laboratory tests have given factors which have an influence on the track-changing effect of various ballast compression forces.  Use of these equivalents, which lie between the first and fourth power, show that for the light track form (S 54 rails, sleeper length 260 cm, sleeper spacing 65 cm), we can expect almost three times the height change which results with the present UIC 60-240-60 design, and the latter almost twice that of the UIC 60-B75-60 design.  A cost comparison shows that the light construction, in spite of its lower first cost, is the least favorable form owing to its high maintenance costs.  A law was developed to determine evaluation figures by means of which various train configurations can be assessed with respect to their track loading.  With the application of the fourth-power law for ballast compression and height change, the load values for the selected passenger trains were in part less, and in part up to 67 per cent greater than for the locomotive-hauled Inter-City trains.  The track loading produced by the extra-heavy ore-carrying freight train was up to 45 times that caused by the locomotive-hauled Inter-City train.]]></description>
      <pubDate>Sat, 26 May 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86005</guid>
    </item>
    <item>
      <title>A PARAMETRIC STUDY OF TRACK SUPPORT SYSTEM</title>
      <link>https://trid.trb.org/View/85982</link>
      <description><![CDATA[The authors of the article describe a few uses of infinite continuous laminated structural supports (ICLSS) in some case studies and sensitivity analyses, which are intended to establish the effects of different parameters on the "static and dynamic-elastic response" of the system.  The parameters studied are: rail size, sleeper size, sleeper spacing, wheel loading, the crib-ballast effect and ballast and subgrade support conditions on the deflections of the rail under the running wheel load.]]></description>
      <pubDate>Fri, 11 May 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85982</guid>
    </item>
    <item>
      <title>DESIGN AND ANALYSIS OF A TRACK COMPLIANCE MEASUREMENT SYSTEM. PHASE II</title>
      <link>https://trid.trb.org/View/81327</link>
      <description><![CDATA[This report covers the design of a vehicle for measuring the static and dynamic compliance of railroad track.  The static compliance system uses the rail deflections due to different axle loads to calculate the track compliance.  The static compliance measurements are taken continuously as the vehicle travels a section of track.  The dynamic compliance system utilizes an electrohydraulic excitation system capable of cyclically applying in-service wheel loads simulating a passing train and superimposing either pulse, random, or sinusoidal dynamic excitation on the wheel load to dynamically excite the track structure.  The excitation and resulting response of the system are analyzed using a digital Fast Fourier Transform program.  From these data, the dynamic characteristics of the track structure can be determined.  The information in this report is intended for use by research personnel who have an interest in railroad track performance as related to vehicle/track interaction and track maintenance, and in the measurement of track deflections and dynamic characteristics for developing track analysis models and evaluating track structure condition.]]></description>
      <pubDate>Tue, 27 Feb 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/81327</guid>
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