Materials and Design 58 (2014) 198–203

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Materials and Design

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Technical Report

The use of deconstructed tire rail pads in railroad tracks: Impact of padthickness

http://dx.doi.org/10.1016/j.matdes.2014.01.0620261-3069/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding author. Tel.: +34 958249445; fax: +34 958246138.E-mail addresses: msol@ugr.es (M. Sol-Sánchez), fmoreno@ugr.es (F. Moreno-Navarro),

mcrubio@ugr.es (M.C. Rubio-Gámez).

Miguel Sol-Sánchez, Fernando Moreno-Navarro, Mª Carmen Rubio-Gámez ⇑Laboratorio de Ingeniería de la Construcción de la Universidad de Granada, C/ Severo Ochoa s/n, 18071 Granada, Spain

a r t i c l e i n f o

Article history:Received 30 September 2013Accepted 24 January 2014Available online 4 February 2014

a b s t r a c t

Deconstructed end-of-life tires are an abundant waste material that can be used to manufacture rail pads.Since tire layers are deconstructed, there is no need to shred and grind them up, which has the advantageof reducing economic costs as well as environmental impacts. However, the mechanical performance ofthis material can be affected by various design parameters, particularly, the thickness of the rail pad. Thisresearch study assessed the impact of thickness on the mechanical performance of deconstructed tire railpad when subjected to loads simulating the passing of trains. The objective was to produce rail padsspecifically designed for railway systems of various types and demands. Accordingly, the static anddynamic response was evaluated as well as the fatigue strength of rail pads of different thicknesses. Inthis sense, thicker rail pads were found to be more flexible and with a greater capacity to damp loads.The results of the study showed that for high-speed railways, the most suitable rail pads were those witha thickness of 7.5–9.0 mm, whereas pads with a lesser thickness were more suitable for conventionalrailroad tracks.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

The vertical stiffness of a railroad track, defined as the ratiobetween a vertical track load and the track deflection caused bythe load, has a strong impact on the bearing capacity and perfor-mance of railways subjected to the movement of passing trains.This is reflected in the fact that a reduction in track stiffness couldincrease the maximum bending moment of the rail (and thus thestresses on it) as well as the plastic deformations in the ballast lay-ers. Moreover, it could produce an increase in the rolling resistanceof trains due to greater energy dissipation by the railroad track[1,2]. In addition, very high track stiffness can lead to an incrementin the dynamic forces transmitted by trains. These forces also neg-atively affect the wheel–rail interface as well as the sleeper–ballastinterface and can lead to the deterioration of track components [3].

In recent decades, various authors [4,5] have tried to define anoptimal track stiffness value, based on different parameters. Thiswould make it possible to design railway systems with high perfor-mance and less susceptibility to track deterioration due to passingtrains. In his study of vertical dynamic loading and dissipated en-ergy, an optimal global vertical stiffness value of 50–78 kN/mmwas defined, depending on train speed [6]. Similarly, other authors

[2] calculated this value at approximately 70–80 kN/mm, based ontrack deterioration (and thus, maintenance expenses) as well as onthe evolution of energy costs. He also explains that the compo-nents with the greatest impact on global vertical stiffness are thebed layers and the elastic elements, which can have a significantinfluence on the performance of the railway system [7].

In order to obtain an optimal global stiffness value, it is custom-ary to insert rail pads between the rail and sleepers. Since the elas-ticity of the rail pads should be in consonance with the specificrequirements and characteristics of each stretch of the railroadtrack, the pads are defined by their stiffness value under the loadsof rolling trains [2,6]. One way to vary this stiffness is to alter thethickness of the pads. This makes it easier to provide the railroadtrack with an optimal global stiffness value. However, the variationof the pad thickness can have different impact on the track perfor-mance depending on the material that the pad is made of [8,9].This means that it is necessary to focus on rail pads made from aspecific material and study the impact of their thickness on padstiffness.

In previous research, the use of rail pads made from decon-structed tires (DT) was found to be an effective solution to dampthe loads and vibrations caused by rolling trains. At the same time,the use of DT rubber let reduce a great quantity of waste materials,which is becoming to be an important task in civil engineering[10]. In addition, this is the source of many environmental andeconomic benefits derived from the recycling of this overly

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abundant waste without having to grind it up. Therefore, in orderto design rail pads with different mechanical properties, thisresearch studied thickness as a parameter that could potentiallyaffect the stiffness of the rail pads. It was thus possible to specifyvarious solutions tailored to achieve optimal track stiffness values,depending on the mechanical performance required of the railwaysystem. For this purpose, the static and dynamic response as wellas the fatigue strength was evaluated for DT rail pads of differentthicknesses.

2. Methodology

2.1. Materials

For this research, rail pads were designed from the externallayer of deconstructed tires (DT) [11], whose main material is rub-ber with appropriated mechanical characteristic to be used in engi-neering applications [12]. The tire rubber was thus obtainedwithout any sort of mechanical processing that modified the prop-erties of this material. Fig. 1 shows how the DT rail pads were man-ufactured. The manufacturing process was carried out in thefollowing stages: (A) deconstruction of the end-of-life tire in differ-ent elastic layers; (B) obtaining pads from the tire tread, whichwere of a suitable size for rail pads; (C) geometric design in conso-nance with the fastening system used to fix the rail to the sleeper;(D) mechanical processing to make the rail pad thickness uniform.

This study analyzed 107 samples with thicknesses of4.0–11.5 mm, given that this range is the most common for railpads [13–15]. Moreover, all samples had the same length andwidth (180 mm � 140 mm), which made them apt for UIC 54 rails.

2.2. Experimental set-up

The mechanical response of the rail pads was evaluated by ana-lyzing their static and dynamic performance (at a load application

Fig. 1. Manufacturing of rail pads.

frequency of 4 Hz) for loads of 20–95 kN. As previous mentioned,the thicknesses of the samples was 4.0–11.5 mm. Similarly, forthe assessment of long-term performance, five rail pads of4.5 mm, 6.0 mm, 7.5 mm, 9.0 mm, and 11.0 mm were analyzed.These thicknesses were selected because they were regarded asthe most representative. It was thus possible to analyze the effectof the thickness of the DT rail pads on the deterioration of theirmechanical response. Furthermore, after the fatigue test, the staticstiffness of the rail pads was again measured to evaluate their lossof mechanical properties. Table 1 outlines the sequence of the testsperformed in this research.

The vertical secant stiffness under loads of 20–95 kN (UNE-EN13146-9) [16] reflects the mechanical performance of the rail padsfor an expected load level on railroad tracks. A load of 20 kN corre-sponds to the force applied by the fastening system, whereas a loadof 95 kN corresponds to the maximum force applied by the trainwheel with a maximum load per axle of 190 kN.

The elastic elements were subjected to three loading cyclesranging from a minimum load of 0.5 kN to a maximum load of95 kN. The maximum load was maintained for one minute andthe minimum load for five minutes with a loading speed of15 kN/min for the first two cycles. In the third loading cycle (load-ing speed of 5 kN/min), the vertical displacements of the rail padwere recorded for loads of 20–95 kN. The parameter thus obtainedwas the secant stiffness (kN/mm) established as the quotientbetween 75 kN and the difference of displacements measured forthe previously mentioned force values. Furthermore, for this load-ing cycle, the vertical displacements measured at the four cornersof the rail pads were recorded.

As part of this study, a dynamic test was also performed to eval-uate the stiffness and energy dissipated by the rail pads underloads simulating the passing of trains on the railroad track. Accord-ingly, 1000 loading cycles were applied at a frequency of 4 Hz(according to UNE-EN 13481-2, Annex B) [17]. The maximum loadwas 95 kN, and the minimum load was 20 kN. In each loadingcycle, the vertical displacements at the four corners of the rail padswere evaluated. This made it possible to assess the evolution of thedynamic stiffness and energy dissipated by these materials.

The fatigue strength of the rail pads was assessed with theLocati method for accelerated fatigue testing [18]. This procedurewas used since in other research [19], the Locati test producedresults that were similar to those obtained with the conventionalfatigue test. Accordingly, four load levels (20/75, 20/90, 20/105,and 20/120 kN) of 50,000 cycles each were applied at a frequencyof 4 Hz. In each cycle, the vertical displacement of the rail padcorners was measured to analyze the evolution of the dynamicstiffness and dissipated energy.

3. Results and discussion

3.1. Static test results

Regarding the impact of the thickness of the rail pads on theirresponse to static compression loads, Fig. 2 shows the secant stiff-ness values obtained at loads of 20–95 kN (range of expected staticloads on high-speed railways) for DT rail pads with thicknesses of

Table 1Test sequence.

Tests No of rail pads Thicknesses (mm)

Static stiffness at 20–95 kN 107 4.0–11.5Dynamic stiffness at 4 Hz 107 4.0–11.5Fatigue strength 5 4.5, 6.0, 7.5, 9.0, 11.0Static stiffness after the fatigue test 5 4.5, 6.0, 7.5, 9.0, 11.0

Fig. 2. Ratio between secant stiffness 20/95 kN and rail pad thickness.

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4.0–11.5 mm. Generally speaking, the results indicated that whentheir thickness was reduced, the rail pads became stiffer. Thiseffect becomes even more pronounced in rail pads with thick-nesses of less than 6 mm. Consequently, in these cases, thicknesshad a strong impact on the mechanical performance of the railpads under compression loads caused by rolling trains. Moreover,it was found that vertical secant stiffness values of 20–95 kN fit apower law with a determination coefficient (R2) equal to 0.8226.This means that the DT rail pads have a wide range of stiffness val-ues, which makes it possible to select the most suitable thickness,depending on the design of the railway system and the loads that itwill be subjected to.

Therefore, for railroad tracks with a low bearing capacity, DTrail pads of reduced thickness (4.5 mm) could be used since theymay reduce deflections produced by the passage of trains. How-ever, excessively stiff tracks (caused by the configuration of theballast and formation layers, concrete sleepers, etc.) require DT railpads of greater thickness so that the track will be more flexible andhave a greater capacity to damp loads. Similarly, this type of railpad would also be suitable for high-speed train tracks. As pointedout by other authors [2,20], such tracks require rail pads with a sta-tic stiffness close to 80–100 kN/mm in order to obtain an optimalglobal vertical stiffness value.

For a more in-depth perspective on rail pad thickness, Fig. 3shows the load-vertical displacement curves recorded in the lastloading cycle of the 20–95 kN secant stiffness test. Results showedin Fig. 3 correspond to rail pads with thicknesses of 4.5 mm,6.0 mm, 7.5 mm, 9.0 mm, and 11.0 mm (which were consideredto be representative of the total sample). The results obtainedshowed that thicker rail pads had larger maximum verticaldisplacements. This means that rail pads of greater thickness arebetter able to damp loads produced by rolling trains and thus toafford better protection for the sleepers and ballast layers [2,21].

Fig. 3. Vertical displacement measurements obtained in the static test for rail padsof different thicknesses.

However, it is also true that larger vertical displacements cansignificantly increase track deflection. This has the disadvantageof increasing the rolling resistance of trains [1] as well as causingfatigue in certain elements of the track superstructure such asthe rail, and fastening system, due to the increase in translationaland rotational movements [2]. This could limit the use of rail padswith thicknesses of approximately 11.0 mm since their maximumvertical displacement values were more than double the values ob-tained for the other samples.

Fig. 4 shows the change in vertical deformation over time forthe last loading cycle in the 20–95 kN secant stiffness test for railpads with thicknesses of 4.5 mm, 6.0 mm, 7.5 mm, 9.0 mm, and11.0 mm. In each case, the greatest variation in vertical displace-ment occurred at the beginning of the loading cycle. This resultagreed with those obtained in previous studies for rubber rail pads[9]. The DT rail pads were thus found to have a non-linear behaviorcaused by the stiffening of the deconstructed tire rubber when thetime and loading level were increased.

The permanent deformation of the samples was also studied.However, the results did not reflect any direct relation betweenthis parameter and pad thickness since the maximum value(0.86 mm) was obtained by the rail pad with a thickness of9.0 mm. In contrast, the pads with thicknesses of 7.5 mm and11.0 mm showed residual deformation values close to 0.57 mm,whereas pads with thicknesses of 6.0 mm and 4.5 mm had evenlower values (approx. 0.39 mm). Nonetheless, elastic recoveryresults do showed direct relation with pad thickness since thickerpads were found to have greater capacity to recover verticaldeformations.

To complete this phase of our study on the static performanceof rail pads of different thicknesses, Fig. 5 shows the stiffness anddissipated energy values for pads with thicknesses of 4.5 mm,6.0 mm, 7.5 mm, 9.0 mm, and 11.0 mm during the last loadingcycle in the 20–95 kN secant stiffness test. When its thicknessincreased, the rail pad had a lower stiffness value and a highercapacity to dissipate energy to the rest of the railway system.Moreover, results showed that DT rail pad with a thickness of11.0 mm obtained higher dissipated energy values than the restof the pads. As pointed out by other authors [1,2], this couldincrease rolling resistance as a consequence of the increase indeflections, thus generating higher exploitation costs.

3.2. Dynamic test results

Fig. 6 shows the evolution in the dynamic stiffness of the railpads with thicknesses ranging from 4.0 mm to 11.5 mm. This testanalyzed the impact of rail pad thickness on their response to re-peated loads. It was observed that in the same way as in the static

Fig. 4. Time–displacement curves recorded in the static test for rail pads ofdifferent thicknesses.

Fig. 5. Static stiffness and dissipated energy values for DT rail pads of differentthicknesses.

Fig. 6. Ratio between the dynamic stiffness and thickness of deconstructed tire (DT)rail pads.

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test, the dynamic stiffness of the rail pads fit a power law(R2 = 0.8002) related to pad thickness. The rail pads thus hadhigher stiffness values as their thickness decreased. This was mostsignificant in the case of rail pads with a thickness of less than6.0 mm. The high stiffness values of these pads signified that theycould not be used in high-speed railroad tracks, which requiremore flexible rail pads [22]. In reference to static stiffness values,it was found that when rail pads with thicknesses of more than6.5 mm went from a static to a dynamic state, their stiffnessincreased up to 3.6 times. This value, which is regarded as suitablefor this type of material, is in consonance with previous studies[23].

In regards to the impact of the thickness of DT rail pads on theirdynamic performance, Fig. 7 shows the change in their dynamicstiffness during each loading cycle for rail pads with thicknesses

Fig. 7. Evolution of dynamic stiffness measured in the dynamic test for DT rail padsof different thicknesses.

of 4.5 mm, 6.0 mm, 7.5 mm, 9.0 mm, and 11.0 mm. These resultsshowed that the thicker pads were also more flexible and betterable to attenuate the stiffness of the railroad track, which wouldpresumably lead to a reduction in dynamic overloads [2] due torolling trains. Furthermore, Fig. 8 shows the impact of pad thick-ness on the energy dissipated by the sample DT pads when sub-jected to repeated loads. As can be observed, increased padthickness produced a corresponding increase in the energy dissi-pated by the rail pads. This could reduce the energy transmittedto the sleepers and the ballast and sub-ballast layers, caused bythe passage of trains.

The combined results in Figs. 7 and 8 show that rail pads withthicknesses greater than 7.5 mm make the railway system moreflexible, and at the same time, reduce the loads transmitted tothe railroad track [2,7]. Accordingly, given the special requirementsfor high-speed train tracks, the most suitable rail pads should havea thickness greater than 7.5 mm whereas rail pads with lowerthickness values could be used in more conventional railways thatrequire a less demanding mechanical performance.

3.3. Fatigue test results

To evaluate the effect of the thickness of DT rail pads on theirlong-term dynamic performance, Fig. 9 shows the evolution indynamic stiffness in relation to the number of cycles for rail padswith thicknesses of 4.5 mm, 6.0 mm, 7.5 mm, 9.0 mm, and11.0 mm. Fig. 9 shows the four load levels applied (20–75 kN,20–90 kN, 20–105 kN, and 20–120 kN), with a total of 50,000cycles each.

The results showed that the impact of the thickness on the dy-namic stiffness of the rail pad was very significant in the case of railpads less than 6.0 mm thick. This effect accentuated as the ampli-tude and number of loading cycles increased. For this reason, therail pad with a thickness of 4.5 mm was too stiff to be used inhigh-speed railway lines. In contrast, rail pads with thickness val-ues higher than 6.0 mm obtained a lower dynamic stiffness valueduring the fatigue test. In this case, when the number of loadingcycles was increased for the four levels, the material stiffeningwas lower than that of rail pad 4.5 mm thick. In addition, theamplitude of the loading cycles had less of an impact on rail padswith a thickness of 7.5 mm or more. Accordingly, as reflected in thedynamic stiffness values recorded in the fatigue test, rail pads withthicknesses greater than 7.5 mm were the most suitable for high-speed train railroad tracks.

During the dynamic mechanical fatigue process, the evolutionof the residual deformation of the samples of different thicknesseswas also evaluated (Fig. 10). It was found that the permanent ver-tical deformation of these rail pads increased in the thicker ones,which thus became less elastic. This could be due to the increase

Fig. 8. Evolution of the dissipated energy measured in each cycle for DT rail pads ofdifferent thicknesses.

Fig. 9. Dynamic stiffness values recorded in the fatigue test of DT rail pads ofdifferent thicknesses.

Fig. 10. Residual deformation measured in the fatigue test of DT rail pads ofdifferent thickness.

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in the maximum deformation of the rail pads when their thicknessincreased. Moreover the most significant change in performancewas observed between rail pads 7.5 mm thick and rail pads9.0 mm thick, as well as between rail pads 9.0 mm thick and railpads 11.0 mm thick. In contrast, in the case of rail pads between4.5 mm and 7.5 mm thick, the effect of the thickness of the railpad on the residual deformation was less accentuated than in therest of the cases. The behavior of these rail pads was thus moreelastic than that of the thicker rail pads.

Furthermore, the impact of the thickness of the rail pads ontheir durability was also evaluated. Fig. 11 shows the change inaccumulated dissipated energy measured during the fatigue test

Fig. 11. Accumulated dissipated energy measured in the fatigue test of DT rail padsof different thicknesses.

of the different samples. Lower dissipated energy values were re-corded for the rail pad with a thickness of 4.5 mm because of itsgreater stiffness. As can be observed, the energy dissipated bythese rail pads increased as pad thickness increased. Thicker railpads thus had a greater capacity to attenuate the loads transmittedto the sleepers and ballast layers. The highest accumulated dissi-pated energy values were recorded for the rail pad with a thicknessof 11.0 mm. However, the use of this type of rail pad could producean increase in energy consumption by trains as a consequence ofthe excessive amount of energy dissipated by these rail pads[1,2]. For this reason, it is advisable to use DT rail pads with thick-nesses of less than 11.0 mm.

In addition to the dynamic analysis of rail pad behavior duringthe mechanical fatigue process, a 20–95 kN static secant stiffnesstest was subsequently performed for rail pads of different thick-nesses. In this test, the static stiffness of all the DT rail pads in-creased less than 15%. This indicates that these rail pads have adurability that makes them suitable for their use in high-speedrailroad tracks.

4. Conclusions

This research studied the impact of the thickness of decon-structed tire rail pads on their mechanical performance and theirpotential use in railroad track systems. The material analyzedincluded 107 rail pads manufactured from rubber sectionsextracted from the tread of deconstructed tires. An evaluationwas performed of their static and dynamic response as well asthe fatigue strength under compression loads simulating passingtrains. The thickness of the DT rail pads ranged from 4.0 mm to11.5 mm since these thicknesses are the most commonly foundin this type of railway element. Based on the results obtained inthe battery of tests performed on the samples, the followingconclusions can be derived:

� The thickness of DT rail pads has a significant impact on theirmechanical performance. These pads have a wide variety ofstiffness values and mechanical properties. It was found thatthicker rail pads had higher levels of static and dynamicflexibility.

� The variation in the static and dynamic stiffness of the DT railpads in relation to their thickness responds to a power law,showing that thickness has a greater impact on the mechan-ical performance of pads less than 6.0 mm thick.

� Thicker rail pads had a better elastic recovery as well asgreater vertical deformations and higher dissipated energyvalues. This indicates that increasing the thickness of the railpad can reduce the loads and vibrations transmitted to thesleepers and ballast and sub-ballast layers of the railroadtrack. Accordingly, for high-speed railways with a high vol-ume of heavy traffic, it is advisable to use DT rail pads withthicknesses of 7.5 mm or more.

� However, the use of DT rail pads with thicknesses approach-ing 11.0 mm could cause rail deflections and excessive dissi-pated energy values, which would make them unsuitable foruse in railroad tracks. This could result in increased mainte-nance and exploitation costs as a consequence of the rapiddeterioration of track elements (rail, fastening system, etc.)and an increase in train rolling resistance.

� The DT rail pads, whatever their thickness, were found tohave acceptable mechanical fatigue strength for use in rail-road tracks. Nevertheless, during the application of repeatedloads, the stiffening of the pads increased as the thicknesswas reduced as well as their capacity to dissipate energydecreased.

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� Accordingly, based on the results obtained in this study, theuse of DT rail pads with a thickness of 7.5 mm or less shouldbe limited to conventional railway lines or to those thatrequire rail pads of medium–high stiffness. In contrast, railpads with a thickness greater than 7.5 mm can be used inhigh-speed railways to reduce dynamic overloads as well asthe stresses and vibrations transmitted to the sleepers andballast and sub-ballast layers of the track. However, fromthe perspective of energy dissipation and fatigue of certainmaterials of the superstructure (mainly, rails and fasteningsystems), it is more advisable for the thickness of the railpad to be limited to values of approximately 9.0 mm, thusavoiding excessive vertical displacements of the rail pads.

References

[1] Fortin JP. La deformée dynamique de la voie. Revue generale des Chemins deFer 1982:93–102.

[2] Fonseca Teixeira P. Contribución a la reducción de los costes de mantenimientode vías de alta velocidad mediante la optimización de su rigidez vertical. TesisDoctoral. E.T.S. Ingenieros de Caminos, Canales y Puertos de Barcelona; 2003.

[3] Prud’Homme A. Forces and behaviour of railroad tracks at very high trainspeeds. Standars adopted by S N C F for its future high speed lines (250 to300 km/h). Proc Symp Rail Track Mech Tech. New Yersey: PrincetonUniversity; 1978.

[4] Raymond G, Bathurst R. Estimate of static track modulus using elasticfoundation models. Transport Res Rec 1994;1470:65–72.

[5] Selig ET, Li D. Track modulus: its meaning and factors influencing it. TransportRes Rec 1994;1470:47–54.

[6] López Pita A. Posibilidades en la reducción de los costes de mantenimiento dela calidad geométrica de una vía, mediante la introducción de nuevos criterios

en su diseño. XVI Pan American Railway Congress: Washington DC; 1984. p.416–463.

[7] Sadkowski A. Modelling of the deformation of elastic pads for rail fastenings.Transport Probl 2009;4(1):63–70.

[8] Kaewunruen S, Remennikov AM. State dependent properties of railpads. University of Wollongong Research Online; 2009.

[9] Folta Z. Mechanical characteristics testing of the rubber elastic pads underrail. Department of Parts and mechanisms of machines, VSB-TechnicalUniversity of Ostrava; 2011.

[10] Sanchez-Alonso E, Castro-Fresno D, Vega-Zamanillo A, Rodriguez-Hernandez J.Sustainable asphalt mixes: use of additives and recycled materials. Baltic JRoad Bridge Eng 2011;VI(4):249–57.

[11] Gomavial Solutions SL. www.gomavial.com [accessed 25.03.13].[12] Davies B. Natural rubber-its engineering characteristics. Mater Des

1986;7(2):68–74.[13] CDM. http://cdmse.com [accessed 29.04.13].[14] Edilon Sedra. www.edilonsedra.com [accessed 29.04.13].[15] Getzner Werstoffe. www.getzner.com [accessed 29.04.13].[16] EN 13146-9:2011. Railway applications. Track. Test methods for fastening

systems. Part 9: Determination of stiffness. European Committee forStandardization. Brussels; 2009.

[17] EN 13481-2 Annex B:2003. Railway applications. Track. Test methods forfastening systems. Par 2: Fastening systems for concrete sleepers. Annex B:Determination of rail pad dynamic stiffness. European Committee forStandardization. Brussels; 2002.

[18] Locati L. Programmed fatigue test, variable amplitude rotate. Metall Ital1952;44(4):135–44.

[19] Carrascal IA et al. Dynamic behaviour of railway fastening setting pads. EngFail Anal 2006;14:364–73.

[20] Kumar Agarwal S. Dynamic Analysis of High Speed Track: A Parametric Study.IPWE Seminar, Pune; 2012

[21] Knothe KL, Grassie SL. Model long of railway track and vehicle/trackinteraction at high frequencies. Vehicle Syst Dyn 1993;22:209–62.

[22] Szurgott P, Gotowicki P, Niezgoda T. Numerical analysis of a shaped rail padunder selected static load. J KONES Powertrain Transp 2012;19(1).

[23] Bouvet P, Vincent N. Laboratory characterization of rail pad dynamicproperties. Vibratec, Report 450.004.RA.05.A, 1998.