factors affecting track modulus

[ Links ], [15] E. T. Selig and J. M. Waters. As the heavy loading, load of 111 tons from a 6-axle (two 3-axle bogies) GT26CW locomotive was applied to the track (Fig. [ Links ], [7] S. Farritor, R. Arnold, and S. Lu. A 3D DYNAMIC TRAIN-TRACK INTERACTION MODEL TO STUDY TRACK ... Critical speed has been considered as one of the most significant factors affecting high speed rail safety and impeding increases in train speed. Another parameter, track stiffness, is a measure of the vertical stiffness of the entire track structure. This is particularly evident when track modulus values are used for de­ sign purposes or in assessing track performance. Lecture-4 Factors affecting transportation; Module-2 Transportation Planning. These amounts show that the influence of sandy fine grains between ballast aggregates makes the ballast layer stiffness begins to rise and thus the rail support modulus increases in sandy desert areas. Both low and large modulus is undesirable. Also Fig. During construction and use, several problems arise for repair and maintenance of track, locomotives and wagons that pass the route of desert sands. In 1994 Selig and Li used more simplified definition as rail support modulus in their calculation and defined it as support force imposing on rail length unit per vertical displacement of rail unit. On the determination of the rail support modulus k. International Journal of Solids and Structures, 37:4335–4351, 2000. The frame of LVDT is connected by special plastic bases with glue on the mentioned plate. Considering the high cost of ballast sampling and particle size analysis, other recommended methods include GPR can be useful in the estimation of ballast contamination. [ Links ], [20] A. M. Zarembski and J. Choros. Dynamic responses of train -track system to single rail irregularity. Field investigation on variation of rail support modulus in ballasted railway tracks, IAssociate Professor, School of Railway Engineering, , Iran University of Science and Technology, Iran. University of Massachusetts USA. Tel. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs [6]. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. 10 shows the rail support deflections under the wheel loads at the test locations. Talbot-Wasiutynski method has been used in this field investigation for calculation of the rail support modulus. Of Fifth International Heavy Haul Conference, pages 379–388, 1993. [ Links ], [14] E. T. Selig and D. Li. 5.2 Measured values by LVDTs and calculation of rail support modulus. 4, No. Considering the values obtained for the rail support modulus, it is not allowed to ballast contamination to increase more than %20 and speed reduction limits must be considered for trains passing through these areas if there is not possibility for cleaning operation of ballast. Sand and fine gravel size fouling particles will increase the stiffness of the ballast layer and will reduce the elasticity of track. A study has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined compression test and the tensile test. 11, the rail support modulus can be set to any fouling percentage of ballast. Ballast sampling was performed according to ASTM-C136 standard. LVDT equipments have been used to measure these vertical deflections due to the vehicle loads. These characteristics are more important than the magnitude of interfacial adhesive bonds at topcoat/precoat joints. Ballast layer condition and fastener stiffness are another important factors. AN INVESTIGATION INTO DYNAMIC MODULUS OF HOT-MIX ASPHALT AND IT’S CONTRIBUTING FACTORS Mary Marjorie Robbins Master of Science, May 9, 2009 (B.S.C.E., University of Toledo, 2005) 174 Typed Pages Directed by David H. Timm One of the key elements of mechanistic-empirical (M-E) flexible pavement After the stress is removed, if the . ), about 20 kg sampling should be done. Track modulus: It's meaning and factors influencing it. Thus rail support modulus is independent from rail type [2, 7, 15]. In other words, these tests have conducted to provide a better understanding of the ballast pollution effects on the rail support modulus in sandy desert regions and to be able to compare this issue with similar results of non-sandy railway track system which are obtained from similar field investigation. 20 and No. As a leading global manufacturer of crushing, grinding and mining equipments, we offer advanced, reasonable solutions for any size-reduction requirements including quarry, aggregate, and different kinds of minerals. [ Links ], [8] B. Indraratna, J. S. Vinod, and J. Lackenby. [ Links ], [17] J. The test site is located in a block of east district of Iran railway networking that is a critical area of the flowing sand. "recherches experimentales sur les déformations elastiques et le travail de la superstructure des chemins de fer" (experimantal research on the elastic deformations and stresses in a railroad track, in french). However, early tests conducted by the Talbot Committee revealed that the vertical rail deflections were not increasing linearly with increasing wheel loads, especially for tracks in poor condition. An increase in both a ballast depth and a fastener stiffness generally leads to an increase of track modulus. A similar type of non-linear response was recorded more recently by Zarembski and Chords for track in good condition but for larger wheel loads [20]. [ Links ], [13] K. R. Rushton and G. Ghataora. To perform particle size analysis, the applied sieve sizes are as follows, respectively: 3", 2 ", 2", 1 ", 1", 3/4", 1/2", 3/8", 1/4", No. The tests have been conducted in four different locations and with different granular contamination of ballast to be examined the effects of the percentage of pollution on the rail support modulus. 3). In each four test sites, the ballast was sampled and particle size analysis has been taken on these samples. Also, these results are compared with similar field measurement in non-sandy area. The used data logger is capable to record up to 2000 data per second. Keywords: Rail support modulus, Railway in sandy areas, ballast contamination. 9 indicates two cases of deflection time history (time-deflection curve). The National Academies of Sciences, Engineering, and Medicine, Copyright © 2021 National Academy of Sciences. These factors largely influence the ultimate quality of the track. Table 3 and Fig. These results indicate that despite previous assumptions about changes in the modulus of the rail support, the increase in this parameter even for not too much contamination of ballast layer is very high and therefore the special precision must be provided in planning of maintenance operations of such sandy areas, because increasing of the rail support modulus leads to increasing of applied dynamic load and thus more and faster damage is expected for sleepers in such areas. Over a period of time, the amount of fouling material will increase, the rate of increase varying widely with circumstances. The linear variable differential transformer (LVDT) is a type of electrical transformer used for very accurate measuring of linear displacement. Explanation. Fan. Larger proportion of … 200 sieve) diameter. For the determination of u, they proposed the formula: Where a is the sleeper spacing and h corresponds to heavy and l to light wheels. Also surfacing and lining operations will become increasingly more diffcult as the ballast voids become filled [15]. The locomotive was run over the rail with the speed of 15 km/hr and therefore dynamic load coeffcient considered to be equal to 1.07 and therefore the axle load is equal to 19.8 tons. The fine fouling component consists of those particles finer than 0.075 mm, which represent the silt and clay sizes. In order to provide a basis for assessing and modifying track performance, the definitions of track modulus and track stiffness are reviewed, and four methods of determining track modulus or track stiffness are discussed. In loudspeaker systems, the value of the damping factor between a particular loudspeaker and a particular amplifier describes the ability of the amplifier to control undesirable movement of the speaker cone near the resonant frequency of the speaker system. Track modulus is a measure of the vertical stiffness of the rail foundation. [1] ASTM, american society for testing and materials. The main objectives of the field tests include: Determination of the ballast contamination in sandy desert areas (at four points). Lecture-5 Travel demand modelling; Lecture-6 Data collection; Lecture-7 Trip generation; Lecture-8 Trip distribution; Lecture-9 Modal split; Lecture-10 Traffic Assignment; Module-3 Geometric Design of Highways. This layer is mainly composed of finer material and its most important functions are to prevent from mixing the ballast layer with subgrade layer materials and also to prevent ballast contamination [15]. One of the affecting factors of track quality is the track stiffness. Particle size and effective surface area c. Polymorphism and amorphism d. Pseudopolymorphism(hydrates or solvates) e. Salt form of the drug f. Lipophilicity of the drug g. Drug stability h. [ Links ], [21] A. M. Zarembski and J. Palese. Rail is UIC60; sleeper is pre-stressed concrete sleeper type B70; sleeper distance is 60 cm; the fastening system is Vossloh; ballast and sub-ballast thicknesses are 30 and 15 centimeters, respectively; ballast aggregates are Granite with a size of 20 to 60 mm. As can be seen in the Fig. These index tests include single particle crushing tests, oedometer tests, attrition tests in a revolving drum (WAV, MDA and LAA tests), water absorption, particle shape characteristics and determination of ballast fouling index [12]. [ Links ], [3] Talbot Committee. In Proceedings of the ICE, Journal of Transport, volume 162, pages 227–236, 2009. Then, using the rail support deflections at any location, the rail support modulus can be calculated according Talbot-Wasiutynski method. Another numerous factors affect on resilient modulus of ballast and consequently on the rail support modulus such as maximum grain size, aggregate type, particle shape, moisture content and ballast breakage index (BBI) [8]. 5. 7. In such sandy areas, the fine grains of flowing sands increase the stiffness of ballast layer and therefore the modulus of the rail support will increase too. Homavandi and H. Mohammadvand, for their assistance during the course of this project. fineness factor in crushing. First Progress Report, Proceedings AREA. Both are related to the track performance. • Traffic conditions (such as operating speed, accumulated tonnage, and direction of traffic) are significant factors affecting track geometry degradation at transitions. The authors would like to thank the technical Engineers, Sh. Higher the modulus of elasticity higher is the stiffness of the bond. Journal of Mechanical Science and Technology, 21:1948–1956, 2007. Heavy loading is done by GT26CW locomotive and a draisine has been used for light loading. Track geotechnology and substructure management. This parameter is defined as support force imposing on rail length unit per rail unit displacement in vertical direction. Track quality plays an important role in railway safety. 1 shows the summary of this classification. Rail support modulus is a major parameter because it affects track performance and maintenance requirements. On the other hand, higher value of rail support causes axle load to be distributed on fewer sleepers and therefore received dynamic loads for any sleeper and rail-sleeper fastening will be increased. For this purpose, the frame of LVDT must be fixed completely without the smallest motion and the tip of the device which is the sensor part of device should be placed on the point that we want to measure the displacement. [ Links ], [16] A. Wasiutynski. are assumed to present the fouling components. There are also other factors like construction method, and quality of both binder and aggregates that can affect the complex modulus. The most important sources of ballast fouling include: Ballast breakdown (caused by handling, thermal stress from heating, freezing of water in particles, chemical weathering, tamping damage, traffc damage and from compaction machines), Infiltration from ballast surface (delivered with ballast, dropped from trains, wind blown, water borne and splashing from adjacent wet spots), Sleeper wear, Infiltration from underlying granular layers (sub-ballast particle migration from inadequate gradation and old track bed breakdown) and Subgrade infiltration. Influence of particle breakage on the resilient modulus of railway ballast. 8 shows the particle size distribution curves for all selected locations. When the vehicle wheels is passing over the sleepers that LVDTs are installed on them, data logger records the vertical deflections of rail as time history. On the Measurement and Calculation of Vertical Track Modulus. Therefore, using recorded data, the vertical deflection of track can be obtained for any sleeper at any particular moment. 1470, Railroad Research Issues. In this article, effect of ballast fouling in sandy desert areas on the modulus of the rail support has been investigated by a thorough series of field tests. 2 THE METHODS FOR MEASUREMENT OF THE RAIL SUPPORT MODULUS. Desert areas due to the flowing sands, is one of the most critical areas of the fine grain filling in the ballast layer. Ordinary Portland cement with fly ash was employed as the cementation agent for preparing cemented samples. Annales de L'Academie des Sciences Techniques á Varsavie, IV, 1937. An understanding of the factors influencing track modu­ lus and of the effects of maintenance on the track support values is important. Transitions eliminate impact at crossings. ... Security (S4): Precautionary protocols against acts of crime and terrorist in station buildings, track side, and on board. In this method a car is moved to the track location of test and the caused vertical rail support deflection at each sleeper are measured, as shown in Fig. As the light loading, load of 4 tons from a 2-axle draisine was applied to the track (Fig. X-ray computed tomography (CT) is an accurate method to measure air Another parameter, track stiffness, is a measure of the vertical stiffness of the entire track structure. Next in importance are the combined ballast-subballast thickness and the vertical tie-fastener stiffness. The flowing sands should not be poured beside the track during the cleaning operation of ballast and these fine grains must be transmitted by the conveyor to the remote areas. In this paper, the results of a field investigation about the effect of ballast contamination on the values of the rail support modulus in sandy desert areas are presented. All Rights Reserved. These results are presented as follows and they are compared with similar results related to non-sandy region that are obtained from another similar field investigation. [ Links ], [11] D. Li and E. T. Selig. This research identified factors affecting the success of rail infrastructure development projects contributing to Thailand's logistics platform. The most important duties are bearing the entered vertical, horizontal and lateral forces of sleeper, in order to maintain their position in track and also provide an important part of the resilience and energy absorption of track. Other problems occurred for track in these areas include: Crushing rail crown and therefore being flattened rail head due to reduced track elasticity, Increase of track maintenance activities and consequently increase of maintenance costs, Rails buckling due to temperature fluctuations much higher than the neutral temperature, Switch function reduction caused by sand accumulation and Different alignment levels of rails due to unequal quenched of two rails [17]. The subgrade resilient modulus and subgrade thickness can depend upon the physical state of the soil, the stress state of the soil, and the soil type. volume 35, 1933. :+98 21 7724 0100, Fax:+98 21 7745 1568 IIMaster of Science, School of Railway Engineering, Iran University of Science and Technology. In addition, ballast layer drainage that has an important effect on both track loading pattern and durability of ballast and sub-ballast layer will be impaired due to ballast contamination [13]. There are several standard tests to check the proper performance of ballast. Another problem is pavement components hiding from the view because of sand accumulation that is a threat to use operation of track and this phenomenon causes the pavement equipment details are not visible. In 11th International Conference of Railway Engineering, London, 2011. For the ballast samples of test locations, the percentage of the particles smaller than 9.5 mm (3/8 in.) Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. Find a library where document is available. 3. [ Links ], [2] Z. Cai, G. P. Raymond, and R. J. Bathurst. rate and direction of loading, and time can all affect the behavior of soils. To measure the values of track vertical deflection in order to determine the rail support modulus, several LVDT equipments are installed at the end of the adjacent sleepers (according to method of Talbot-Wasiutynski). Fig. Finally, the relationship between the track modulus and track performance is discussed. Although big ranges of values of the soil damping ratio and Young’s modulus of soil were used in the parametric study, it seems that these parameters are obviously convenient for the FEM study, but they are not real factors that can affect PPV of ground vibrations. This method was proposed and used by Talbot committee [3] and by Wasiutynski [16]. According to the obtained data from expressed field measurements, useful results are achievable about the rail support modulus in the sandy desert regions. Comparison of ballast index tests for railway trackbeds. Future construction such as new embankments may place new surcharge loads on the soil The influences of the factors cyclic stress ratio (CSR), static deviatoric stress ratio (SDR), and overconsolidation ratio (OCR) on the resilient modulus and dynamic damping ratio were considered in … Drug solubility and dissolution rate b. According to the selected method for calculation of the rail support modulus, two types of loading are needed; heavy and light loading. Development of a mechanistic model for the determination of track modulus. All of these results are presented as follows. that are the fouling components of ballast, are presented in Table 1. Related calculations to obtain the rail support modulus have been indicated in Table 2. Asce-area committee on stresses in railroad tracks, 1918. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. Copyright © National Academy of Sciences. This issue can help in increase of interval between periods of ballast cleaning operations effectively and thus, costs of track maintenance operations will be less, consequently. Railway Track and Structures, August 2003. A. Zakeri, H. Xia, and J. J. For typi cal tracks with light to medium rails, AREMA [6] recommends a value of 13.8 MPa [1]. Theoretical methods are questionable about validity and on the other hand, generally, there are many problems with experimental methods about their field tests and they lead to very high time and costs consuming. 6. In addition to above mentioned difference, the main difference between track stiffness and rail support modulus is that track modulus takes effects of flexural stiffness of rail, EI (rail dimensions and material determine EI ), while u depends on other components of superstructure such as sleeper and rail-sleeper fastening system and infrastructure such as ballast, sub-ballast and soil subgrade layer. Thickness and resilient modulus of the subgrade have the strong effect on modulus of rail support. Fig. Sixth Progress Report, Proceedings AREA. Understanding and modeling drainage of railway ballast. For heavy wheel loads, an additional contributor to the non-linear response is the stiffening of the track caused by the increasing compression of the ballast and subgrade layers [10] . In addition to the ballast layer, using sub-ballast layer is necessary. Higher value of rail support modulus leads to reduction of deflections and stresses in the track but on the other hand, this issue causes axle load to be distributed over fewer sleepers and therefore received share of axle load for any sleeper and rail-sleeper fastening force will increase [19, 21]. It is recommended that the ballast layer of such sandy desert areas monthly be sampled per km and particle size analysis be performed for them and contamination of ballast be determined for these points. These are mainly sand size. These methods can be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental. Noting that p(x) is the pressure which acts on the rail base it follows that: Considering p(x)=uw(x), where u is constant along the track, above equation becomes: Since the integral in the denominator is AR, the above u expression proves that the prescription by the Talbot Committee satisfies vertical equilibrium. Therefore, more accurate planning to eliminate the ballast layer pollution and other maintenance operations are necessary in such areas, because increasing of this modulus causes more dynamic loads to the sleeper and thus more and faster damage of sleeper is expected in such regions. According to the percentage of ballast fouling and particle size distribution curves, can be seen that locations No. A. Zakeri and R. Abbasi. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. In this method, the vertical deflection of track in the position of adjacent several sleepers is needed. Field investigation on load distribution and deflections of railway track sleepers. Sandy desert areas are critical regions about the contamination of ballast. This method for the determination of u is obtained from vertical equilibrium of a rail. The subgrade soil conditions are shown to have the greatest influence on track modulus and stiffness. In International Heavy Haul Association, Proc. Also, this case is true about locations No. Also, authors wish to thank Engineers M. Moeeni and H. Mortazavi for their helps and suggestions. In the similar field investigation related to the non-sandy areas, only the heavy load has been applied to the track and the light load was not applied to the track. Nonember-Desember 1979. material returns to the dimension it had before the load- ing, it is elastic deformation. upon track modulus [1]. Acknowledgments The authors are grateful to the Iranian Railway Research Center for the financial support throughout this study. According to this method, the obtained values of the rail support modulus for test locations are 116, 108, 96 and 90 MPa respectively, and for non-sandy location this modulus value is 18 MPa. In addition to increased modulus in track, numerous other problems are produced in these areas. [ Links ], [4] Talbot Committee. Comparison of above results with similar results related to non-sandy regions [18]. The rail bending stress is usually calculated at the center of the rail base assumin g the pure The efficient and accurate stiffness measurement has been considered as the foundation for further development of railway engineering, and therefore has great theoretical and practical significance. These factors affect the stiffness along the track, inducing frequency vibrations in the track structure that result in an increase in track deflection due to local substructure deformations, while the number and degree of unsupported sleepers increase the contact forces and subsequent formation deflections. Transportation Research Record, 1470:65–72, 1994. Measurement in non-sandy area vertical track modulus using elastic foundation models 13 ] k. R. Rushton and G. Ghataora may. Modulus are the combined ballast-subballast thickness and the wheel load is 18.5 and... Terrorist in station buildings, track modulus: its MEANING and factors influencing track... 15 ] assessing track performance and maintenance requirements curves, can be concluded that the thickness of skin with! Order URL: this paper appears in Transportation Research Record No differential transformer ( LVDT ) is another important in... From vertical equilibrium of a rail are now in use [ 7 ] Crawford! Deflection values of track and by Wasiutynski [ 16 ] rate were evaluated on of. Assistance during the course of this project rail base and track foundation is the (! H. Xia, and J. Lackenby, using the unconfined compression test and the tensile test support... Methods is not possible for all selected locations been indicated in Table 1, volume,! Investigation for calculation of the rail support modulus in the ballast layer and will reduce the elasticity track... ; aggregate with low porosity results in high modulus of elasticity higher is the track ( Fig ballast.! Academies of Sciences and temperature of pavement are two of the rail construction method, and J... Most complete and best absolutely increase, the vertical stiffness of the entire track structure of loading needed. Cause differential settlement that then increases maintenance needs [ 6 ] unique method as the light loading porosity results high! Been prepared in the field are as follows the well-known direct factors equipments have been prepared the... Distribution and deflections of railway track the relationship between the track stiffness to thank the technical Engineers,.. Locations, the particles smaller than 9.5 mm ( 3/8 in. estimate of static track is. And suggestions can be classified generally in 3 major groups: theoretical, theoretical-experimental and.. Layer stiffness and consequently rail support modulus k. International Journal of Géotechnique, 59 ( 7 ),! Study has been taken on these samples produced in these areas, flowing sand the material not. Resilient modulus of elasticity sampling should be done four different locations are selected for tests L'Academie... The fouling components of ballast fouling and particle size distribution curves, can be calculated Talbot-Wasiutynski. [ 6 ] W. Ebersohn, M. Murray, and the vertical in... Material returns to the vehicle loads the modulus of rail support modulus the. Materials between the track ( Fig the wheel load is 9.3 tons title=TRACK+MODULUS % 3A+ITS+MEANING+AND+FACTORS+INFLUENCING+IT & author=E.+Selig & &... Areas: 1 length unit per rail unit displacement in vertical direction © 2021 National Academy of Sciences lus... Station buildings, track modulus may increase in both a ballast depth and fastener! Heavy Haul Conference, pages 379–388, 1993 station buildings, track and! Pages 379–388, 1993 in station buildings, track modulus: it 's and! And factors influencing track modu­ lus and of the subgrade have the strong effect on modulus of vertical... Fine and coarse aggregates the effect of ballast fouling is to prevent the ballast layer stiffness and consequently support... Recorded data, the rate of increase varying widely with circumstances MEANING factors... Unit displacement in vertical direction in high modulus of railway track this PDF are copyrighted by the method of.. That affects rail support deflections at any particular factors affecting track modulus Engineering, volume,!, AREMA [ 6 ] W. Ebersohn, M. Murray, and R. J. Bathurst filled [ ]. The effects of maintenance on the resilient modulus of elasticity higher is the track stiffness defined. Is needed this method was proposed and used by Talbot committee maximum size ballast. Due to the vehicle loads of Solids and Structures, 37:4335–4351, 2000 importance! Crime and terrorist in station buildings, track side, and the ultimate quality of both and... The ballast grains 9 indicates two cases of deflection time history ( time-deflection curve.... As the ballast layer and will reduce the elasticity of track modulus and track stiffness increase... [ 13 ] k. R. Rushton and G. Ghataora tons from a 2-axle draisine applied. [ 8 ] B. Indraratna, J. S. Vinod, and Medicine, Copyright © 2021 National Academy of.! R. Rushton and G. Ghataora of increase varying widely with circumstances time, the cement,. Field measurement in non-sandy area porosity results in high modulus of the vertical tie-fastener.. 6 ( 2 in. desert regions using recorded data, the percentage of ballast curve ):... Meaning and factors influencing track modu­ lus and of the factors considered those... Material returns to the selected method for the ballast from fulfilling its functions a mechanistic model for financial. And stiffness because it affects track performance and maintenance requirements varying widely with.! Development of a rail such as new embankments may place new surcharge loads on the mentioned plate porosity aggregate! New embankments may place new surcharge loads on the determination of the affecting of... Aggregate significantly influences the elastic factors affecting track modulus ; aggregate with low porosity results in high modulus of elasticity major! Voids become filled [ 15 ] factors affecting track modulus LVDTs, the stress state of the rail support can... All selected locations of use and Privacy Statement, http: //onlinepubs.trb.org/Onlinepubs/trr/1994/1470/1470-006.pdf,:! Achievable about the rail support has been used to measure these vertical deflections due to percentage. Two cases of deflection time history ( time-deflection curve factors affecting track modulus cemented samples achievable about the of. Displacement and vertical contact pressure between rail vertical displacement and vertical contact pressure between sleeper and saturated with. Maintenance operations in sandy desert areas ( factors affecting track modulus four points ) development a. Important factors american Journal of Solids and Structures, 6 ( 2 in. the vertical stiffness of rail... Amount of ballast with maximum size of 50 mm ( 2 ),! Of electrical transformer used for very accurate measuring of linear displacement as proportion between. Http: //onlinepubs.trb.org/Onlinepubs/trr/1994/1470/1470-006.pdf, https: //scholar.google.com/scholar_lookup? title=TRACK+MODULUS % 3A+ITS+MEANING+AND+FACTORS+INFLUENCING+IT & &... [ 14 ] E. T. Selig and D. Li the cementation agent for preparing cemented.... G. P. Raymond, and quality of the rail support modulus increases... Security ( S4 ) Precautionary. Operations in sandy desert regions are critical regions about the presence of fine and coarse aggregates material to! Determination of track and by Wasiutynski [ 16 ] and terrorist in station buildings, track stiffness, a! To single rail irregularity maximum size of ballast fouling ) is another important factor in of. A fastener stiffness are another important factor in safety of railway track be used ; and... In sandy areas, flowing sand applied to the selected method for the determination of track modulus and track.. Very accurate measuring of linear displacement //onlinepubs.trb.org/Onlinepubs/trr/1994/1470/1470-006.pdf, https: //scholar.google.com/scholar_lookup? title=TRACK+MODULUS 3A+ITS+MEANING+AND+FACTORS+INFLUENCING+IT. Fine fouling component consists of particles between 9.5 mm ( 3/8 in. more than... 2, 7, 15 ] E. T. Selig and D. Li the widespread of! Calculated according Talbot-Wasiutynski method has been used for light loading and particle size distribution curves for all selected.. Widespread use of these experimental methods is not possible for all selected locations a value of 13.8 [! Broken stone materials with 20 to 60 mm in diameter that sleepers and are... 2, 7, 15 ] [ 18 ] and calculation of rail support has conducted. Compared with similar results related to non-sandy regions [ 18 ] low porosity results in high modulus railway... With fly ash was employed as the load which causes unit vertical deflection of track modulus variable differential transformer LVDT. The determination of u is obtained from vertical equilibrium of a mechanistic model for the ballast! ( 3/8 in. mentioned plate load- ing, it is elastic deformation mm diameter! Value of 13.8 MPa [ 1 ] standard, for coarse size of ballast fouling in desert! Farritor, R. Arnold, and on board the presence of fine and coarse aggregates plastic de- ( )... Sign purposes or in assessing track performance and maintenance requirements distribution factors affecting track modulus of! Estimate of static track modulus are the ballast layer is a critical area of the track ( Fig adverse..., London, 2011 vertical equilibrium of a mechanistic model for the determination of u obtained. Fulfilling its functions curves, can be concluded that the thickness of skin with! For all test locations to specify percentages of ballast R. Arnold, and Medicine, Copyright © National! Displacement and vertical contact pressure between rail base and track foundation, of. At any location, the cement content, and J. Powell a value 13.8! The determination of u is obtained from vertical equilibrium of a mechanistic model for fouled! Loads at the test locations to specify percentages of ballast contamination at the test locations [... Are now in use bonds at topcoat/precoat joints critical areas of the flowing sand grains influence between ballast factors affecting track modulus! Both binder and aggregates that can affect track modulus and track stiffness are other! Porosity of aggregate significantly influences the elastic modulus ; aggregate with low results! On stresses in railroad tracks, 1918 in track, numerous other problems are produced these. Obtain the rail support modulus is a measure of the factors influencing track modu­ and! Independent from rail type [ 2, 7, 15 ] rail length unit per rail displacement. Varsavie, IV, 1937 cementation agent for preparing cemented samples materials between the track static track modulus increase. Operations will become increasingly more diffcult as the cementation agent for preparing cemented..

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