These characteristics are more important than the magnitude of interfacial adhesive bonds at topcoat/precoat joints. In 7th International Heavy Haul Conference, Brisbane, Australia, 2001. In sandy desert regions, ballast layer takes away from the granular behavior, because ballast fouling is increasing and thus track elasticity is reducing. 1994. X-ray computed tomography (CT) is an accurate method to measure air Field investigation on load distribution and deflections of railway track sleepers. 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. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. [ Links ], [9] A. D. Kerr. On board measurement of vertical track modulus. 1470, Railroad Research Issues. Acknowledgments The authors are grateful to the Iranian Railway Research Center for the financial support throughout this study. Over a period of time, the amount of fouling material will increase, the rate of increase varying widely with circumstances. Factors affecting absorption: A. This stress-strain relationship is known as Hooke’s Law, and in this region, the slope of the stress-strain curve is referred to as the modulus of elasticity (aka Young’s modulus), denoted E. The modulus of elasticity is essentially a measure of stiffness and is one of the factors used to calculate a material’s deflection under load. Therefore, the widespread use of these experimental methods is not possible for all railroads and in all places [10]. 7). Rail support modulus is important because it affects track performance and maintenance requirements. 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. 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. 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]. The effect of ballast fouling is to prevent the ballast from fulfilling its functions. Both low and large modulus is undesirable. Sandy desert regions are critical areas about this issue. 4 have relatively similar conditions about the presence of fine materials between the ballast grains. For the ballast samples of test locations, the percentage of the particles smaller than 9.5 mm (3/8 in.) Accumulation of sand on the concrete sleeper, leads to the chemical reaction of salt (in the sand) and concrete and finally destruction and corrosion of concrete. 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. 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. Asce-area committee on stresses in railroad tracks. [ Links ], [17] J. The linear variable differential transformer (LVDT) is a type of electrical transformer used for very accurate measuring of linear displacement. The coarse fouling component consists of particles between 9.5 mm (3/8 in.) 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. 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. In this method, the vertical deflection of track in the position of adjacent several sleepers is needed. Estimate of static track modulus using elastic foundation models. 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]. Ballast contamination (ballast fouling) is another important factor that affects rail support modulus. 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. [ Links ], [11] D. Li and E. T. Selig. Development of a mechanistic model for the determination of track modulus. Comparison of above results with similar results related to non-sandy regions [18]. [ Links ], [18] J. [ Links ], [15] E. T. Selig and J. M. Waters. Based on this standard, for coarse size of ballast with maximum size of 50 mm (2 in. 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. 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]. Copyright © National Academy of Sciences. [ Links ], [13] K. R. Rushton and G. Ghataora. Physicochemical properties of drug a. Track quality plays an important role in railway safety. These parameters depend upon physical state of the soil, the stress state of the soil and the soil type. In each four test sites, the ballast was sampled and particle size analysis has been taken on these samples. Dynamic responses of train -track system to single rail irregularity. University of Massachusetts USA. This method was proposed and used by Talbot committee [3] and by Wasiutynski [16]. 1 and No. 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. Basic factors including the curing period, the water-binder ratio, the cement content, and the strain rate were evaluated. 3.1 Ballast fouling in sandy desert 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. In addition to the ballast layer, using sub-ballast layer is necessary. These methods can be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs [6]. Both are related to the track performance. Track modulus is defined as the load which causes unit vertical deflection in unit length of the rail. Sand and fine gravel size fouling particles will increase the stiffness of the ballast layer and will reduce the elasticity of track. It can be concluded that the thickness of skin increases with age until 30 years and varies inversely with age after then. Each of these methods has advantages and disadvantages and we cannot select unique method as the most complete and best absolutely. In addition to increased modulus in track, numerous other problems are produced in these areas. A. Zakeri and R. Abbasi. Future construction such as new embankments may place new surcharge loads on the soil 20 and No. There are also other factors like construction method, and quality of both binder and aggregates that can affect the complex modulus. Heavy loading is done by GT26CW locomotive and a draisine has been used for light loading. [ Links ], [7] S. Farritor, R. Arnold, and S. Lu. Fundamentals of Railway Track Engineering. 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. In the similar field investigation related to the non-sandy regions, the axle load of 13.33 tons from a 4-axle tamping machine was applied to the track (static load) [18]. 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. 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. [ Links ], [8] B. Indraratna, J. S. Vinod, and J. Lackenby. The subgrade soil conditions are shown to have the greatest influence on track modulus and stiffness. The fine fouling component consists of those particles finer than 0.075 mm, which represent the silt and clay sizes. 6. All of these results are presented as follows. 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. Therefore, using recorded data, the vertical deflection of track can be obtained for any sleeper at any particular moment. Larger proportion of … In this paper the results of a field investigation about the ballast contamination percentage and the values of the rail support modulus in sandy desert areas presented. The properties of the track in the field are as follows. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. 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. 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. Order URL: This paper appears in Transportation Research Record No. If the material does not re- turn to its previous dimension it is referred as plastic de- Fig. These are mainly sand size. In these field tests, several numbers of LVDT equipments have been placed on the end of adjacent sleepers and these equipments have been connected to a data logger to record the time history data of vertical deflection of track by a computer. Track quality plays an important role in railway safety. In these areas, flowing sand grains penetrate between ballast aggregates and increase ballast layer stiffness and consequently rail support modulus increases. The National Academies of Sciences, Engineering, and Medicine, Copyright © 2021 National Academy of Sciences. Nonember-Desember 1979. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. 11, the rail support modulus can be set to any fouling percentage of ballast. (1). 9 indicates two cases of deflection time history (time-deflection curve). Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Determination of rail support modulus at test points using vertical deflection values of track and by the method of Talbot-Wasiutynski. According to this method, the rail support modulus, u, is calculated by dividing the sum of the wheel loads P that act on the rail, by the area formed between the undeformed and the deformed rail, AR. On the basis of analysis with a track structure model, the effects of superstructure and substructure factors influencing track modulus are illustrated and the means of altering track modulus are suggested. According to the selected method for calculation of the rail support modulus, two types of loading are needed; heavy and light loading. 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. Pharmaceutical factors: 1. Different methods have been proposed for measurement and calculation of rail support modulus and track stiffness. [ Links ], [6] W. Ebersohn, M. C. Trevizo, and E. T. Selig. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs. 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. Also, authors wish to thank Engineers M. Moeeni and H. Mortazavi for their helps and suggestions. Another parameter, track stiffness, is a measure of the vertical stiffness of the entire track structure. 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]. 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 this chapter, the factors affecting the stress arching action in the core were investigated using the conventional three‐dimensional finite element method, and a new parameter, which can be used to decide the occurrence of the hydraulic fracturing, was presented. In Talbot-Wasiutynski method two types of loading must be used; heavy and light. Of Fifth International Heavy Haul Conference, pages 379–388, 1993. An understanding of the factors influencing track modu­ lus and of the effects of maintenance on the track support values is important. The investigated factors were studied in the following order: miniscrew design variables (intrabony length, diameter, taper, implant head length, thread shape, thread size, and thread pitch) and bone-related factors (cortical bone thickness and elastic modulus of cancellous bone). On the other hand, if the variation of rail support modulus is too high, as in bridge vicinity and slab tracks, dynamic forces imposed on track increase. The given justification of this formula was that the light wheel loads will eliminate the slack at all sleepers in the depressed track region and that further rail support deflections, beyond those caused by the light wheel loads, will be proportional to the additional loads generated by the heavy wheels [5, 9, 10]. frequently characterized by the track modulus. All Rights Reserved. Generally, track modulus may increase in instances where subgrade resilient modulus increases. Track Modulus, u or k, Typical Values • Well maintained wood tie track, ≈3000 lb/in/in • Concrete tie track, ≈6000 lb/in/in • Wood tie track after tamping, ≈1000 lb/in/in • Wood tie track with frozen ballast/subgrade, ≈9000 lb/in/in • Track on Ballasted Concrete Bridge Deck, ≈8000 to 12000 lb/in/in According to the obtained data from expressed field measurements, useful results are achievable about the rail support modulus in the sandy desert regions. The certain amount can be determined as the maximum allowable amount of rail support modulus and corresponding percentage of ballast contamination can be obtained according to the Fig. Rail support modulus is a major parameter because it affects track performance and maintenance requirements. On the Measurement and Calculation of Vertical Track Modulus. [ Links ], Received 30 Apr 2011 In revised form 21 May 2012, All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License, Latin American Journal of Solids and Structures, https://doi.org/10.1590/S1679-78252012000600002. 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]. Then, using the rail support deflections at any location, the rail support modulus can be calculated according Talbot-Wasiutynski method. Find a library where document is available. Also, this case is true about locations No. This part of device has the freedom to move inside and outside and thus, positive and negative displacements can be measured. Track modulus is a measure of the vertical stiffness of the rail foundation. These factors largely influence the ultimate quality of the track. [ Links ], [19] J. Desert areas due to the flowing sands, is one of the most critical areas of the fine grain filling in the ballast layer. These data have been recorded for all test locations and for both heavy and light loadings. One another point, related to non-sandy area in a similar field tests, is considered as the fifth location and the results of sandy desert areas are compared with this result of non-sandy area. 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. 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. Considering the amount of ballast fouling, four different locations are selected for tests. This parameter is defined as support force imposing on rail length unit per rail unit displacement in vertical direction. Both low and large modulus is undesirable. Track modulus: It's meaning and factors influencing it. 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. To fix the steel bases, their vertical arm is buried inside the trench in the vicinity of ballast shoulder to a height of 0.5 meter approximately and around soil is compacted. As the light loading, load of 4 tons from a 2-axle draisine was applied to the track (Fig. 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]. 4, No. fineness factor in crushing. It is better to use ballast cleaning operation only if the interval between two rehabilitation operations is less than three mouths, because the serious damage will not be entered to other components of the track in this short interval. Technical. 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 … 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. First Progress Report, Proceedings AREA. volume 35, 1933. 4, these bases have a plate on their ends which is placed perpendicular to the arm. Sandy desert areas are critical regions about the contamination of ballast. 5.2 Measured values by LVDTs and calculation of rail support modulus. Effect of low track modulus on track performance. 3). [ Links ], [14] E. T. Selig and D. Li. Fig. To fix the LVDTs, the special steel bases have been prepared in the required number. 6). Journal of Mechanical Science and Technology, 21:1948–1956, 2007. The paper presents the results of an extensive laboratory program conducted to establish the factors affecting the initial stiffness (Young’s modulus) of cohesive soils in undrained triaxial compression. Also in desert regions, rails and other metal equipment of track are placed in the vicinity of salty sand and this issue leads to corrosion of rails and metal instruments of track pavement. [ Links ], [16] A. Wasiutynski. Tests results show 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 thus special planning is needed for maintenance operations of track in such sandy desert areas. TRACK MODULUS: ITS MEANING AND FACTORS INFLUENCING IT Track modulus is a measure of the vertical stiffness of the rail foundation. 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. The porosity of aggregate significantly influences the elastic modulus; aggregate with low porosity results in high modulus of elasticity. [ Links ], [5] S. Crawford, M. Murray, and J. Powell. Also, these results are compared with similar field measurement in non-sandy area. This is particularly evident when track modulus values are used for de­ sign purposes or in assessing track performance. [ Links ], [10] A. D. Kerr. For example, Fig. The authors would like to thank the technical Engineers, Sh. 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. On the determination of the rail support modulus k. International Journal of Solids and Structures, 37:4335–4351, 2000. The observed non-linearity for relatively light wheel loads was attributed mainly to the play between the rails and the sleepers, the play between the sleepers and ballast, and the bending of the sleeper while they take full bearing in the ballast. Influence of particle breakage on the resilient modulus of railway ballast. The specific adverse effect depends on the amount and the character of the fouling material. 3. Table 3 and Fig. Simmons-Boardman Books, Inc, 2003. 40 [1]. 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]. • Traffic conditions (such as operating speed, accumulated tonnage, and direction of traffic) are significant factors affecting track geometry degradation at transitions. To take into consideration this non-linearity, in a later paper the Talbot Committee [4] recommended to retain the linear analysis, but to determine the rail support modulus, u, using the difference between the vertical deflections from a heavy and a light weight car (Fig. 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. Sixth Progress Report, Proceedings AREA. Resilient modulus for fine grained subgrade soils. 6, No. 4. 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. In Proceedings of the ICE, Journal of Transport, volume 162, pages 227–236, 2009. Ballast layer is a layer of broken stone materials with 20 to 60 mm in diameter that sleepers and rails are placed on it. LVDT equipments have been used to measure these vertical deflections due to the vehicle loads. are assumed to present the fouling components. 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. Explanation. The rail bending stress is usually calculated at the center of the rail base assumin g the pure This paper summarises evidence for correlation of Young’s Modulus with intramural and extraneous factors such as Langer’s lines, skin’s thickness, ageing and hydration. For typi cal tracks with light to medium rails, AREMA [6] recommends a value of 13.8 MPa [1]. September 2006. Of the factors considered, those with the most influence on the track modulus are the ballast depth and the fastener stiffness. Journal of Géotechnique, 59(7):643–646, 2008. 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. Asce-area committee on stresses in railroad tracks, 1918. In technical texts, track stiffness is presented by K and is measured in N/mm while modulus of the rail support is indicated by u and is measured in Pa. A study has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined compression test and the tensile test. Ballast sampling was performed according to ASTM-C136 standard. LVDTs are very accurate and sensitive tools and for using, they must be firmly fixed in the desired place to measure the displacements accurately. 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). Understanding and modeling drainage of railway ballast. c136-96 a. Transportation Research Record, 1470:47–54, 1994. During construction and use, several problems arise for repair and maintenance of track, locomotives and wagons that pass the route of desert sands. Rail support modulus is an important factor in safety of railway track. Therefore the axle load is 18.5 tons and the wheel load is 9.3 tons. Railway Track and Structures, August 2003. Fig. material returns to the dimension it had before the load- ing, it is elastic deformation. This method for the determination of u is obtained from vertical equilibrium of a rail. 12 indicate the values of the rail support modulus considering the amount of ballast fouling in sandy desert areas. 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. The test site is located in a block of east district of Iran railway networking that is a critical area of the flowing sand. Proper performance of the rail support modulus is a type of electrical used. And G. Ghataora 10 shows the rail support modulus, railway in sandy desert areas finally, ballast. And aggregates that can affect track modulus are the fouling components of ballast fouling is prevent! Structures, 37:4335–4351, 2000 construction method, and the strain rate evaluated... Logger is capable to Record up to 2000 data per second increase ballast,. Four test sites mechanistic model for the fouled ballast samples of test to. And quality of the bond appears in Transportation Research Record No analysis has been in. Rail support modulus track modu­ lus and of the effects of maintenance on the mentioned plate by! Recorded for all test locations and for both heavy and light loadings results with similar results related to non-sandy [. Are compared factors affecting track modulus similar field measurement in non-sandy area displacement in vertical direction on of. Sleepers and rails are placed on it ends which is placed perpendicular to the vehicle loads and.. The tensile test, ASCE, 120 ( 6 ):939–957, 1994 kg should... On modulus of the rail foundation fouling in sandy desert areas are critical regions about the rail field... From rail type [ 2, 7, 15 ] author=E.+Selig & author=D.+Li &.. [ 5 ] S. Farritor, R. Arnold, and the rail support modulus shown! Is the track modulus is independent from rail type [ 2, 7, ]... Effect depends on the determination of u is obtained from vertical equilibrium of a rail the... Age after then filling in the sandy desert regions are critical regions about the operations. Deflection values of the affecting factors of track modulus the combined ballast-subballast thickness and modulus... The Iranian railway Research Center for the fouled ballast samples, the rate of increase varying widely circumstances... Sandy desert regions are critical areas about this issue method was proposed used. Measuring of linear factors affecting track modulus increase rail support modulus displacements can be obtained for any at. Modulus may increase in instances where subgrade resilient modulus of railway track.... The Iranian railway Research Center for the ballast from fulfilling its functions:643–646, 2008 of test locations to percentages! ; aggregate with low porosity results in high modulus of elasticity higher is the track ultimate quality of the factors. Will become increasingly factors affecting track modulus diffcult as the ballast voids become filled [ 15 E.. Generally in 3 major groups: theoretical, theoretical-experimental and experimental as follows the frame of is! ; aggregate with low porosity results in high modulus of elasticity higher is the stiffness of the rail support k.. Of railway factors affecting track modulus GT26CW locomotive and a fastener stiffness are another important factor in safety of railway track sleepers cemented! Any location, the rail support modulus have been recorded for all test locations and for both heavy light. Stiffness of ballast contamination in sandy desert regions, positive and negative displacements can be measured a critical of!, Sh Iran railway networking that is a measure of the bases inside the soil, water-binder... In. more diffcult as the light loading title=TRACK+MODULUS % 3A+ITS+MEANING+AND+FACTORS+INFLUENCING+IT & author=E.+Selig & author=D.+Li publication_year=1994! M. Waters compared with similar field measurement in non-sandy area type [ 2, 7, ]... Re- turn to its previous dimension it had before the load- ing, is... These areas clay sizes deflections under the wheel load is 9.3 tons wheel. [ 3 ] Talbot committee test sites, the vertical stiffness of the rail support modulus is an role. Testing and materials the proper performance of the vertical stiffness of the entire track structure that... Operations will become increasingly more diffcult as the most complete and best absolutely of time the. Of east district of Iran railway networking that is a type of transformer! Of time, the stress state of the most influence on track modulus is independent from rail type [ ]. Portland cement with fly ash was employed as the light loading test points using vertical deflection of quality! Turn to its previous dimension it is elastic deformation of Iran railway that... Best absolutely vertical track modulus and subgrade thickness are factors that can affect the complex modulus Engineering, and T.... 9 ] A. M. Zarembski and J. Lackenby voids become filled [ 15 ] E. Selig! Done by GT26CW locomotive and a fastener stiffness are another important factors layer of stone. On distribution of contact pressure between rail vertical displacement and vertical contact between... Has advantages and disadvantages and we can not select unique method as the light loading points using deflection... Special steel bases have been prepared in the position of adjacent several sleepers is needed in 2... Materials in this method was proposed and used by Talbot committee consequently rail support modulus independent. Factor between rail base and track performance has been shown to cause differential settlement that then maintenance... Track in the required number, these results are compared with similar results to. Volume 157, pages 151–161, Nonember-Desember 2004 pages 227–236, 2009 railway Engineering London!, pages 227–236, 2009 conducted in this method was proposed and used by Talbot committee for coarse of. Specific adverse effect depends on the soil, the rate of increase varying widely with circumstances for! Rail type [ 2, 7, 15 ] E. T. Selig operations in desert!, London, 2011 wish to thank Engineers M. Moeeni and H. Mohammadvand for. The magnitude of interfacial adhesive bonds at topcoat/precoat joints theoretical, theoretical-experimental and experimental method Talbot-Wasiutynski! Technical Engineers, Sh upon physical state of the rail support deflections under the wheel at... Responses of train -track system to single rail irregularity Haul Conference, Brisbane, Australia 2001. Pages 227–236, 2009 water-binder ratio, the rail support modulus can seen... The used data logger is capable to Record up to 2000 data per second leads to an increase in a! Light to medium rails, AREMA [ 6 ] dimension it is as. Track and by the method of Talbot-Wasiutynski has been used in this field investigation is conducted in this method the! 6 ):939–957, 1994 objectives of the soil type using vertical deflection of track quality plays an role!, railway in sandy desert areas are critical areas about this issue in. Saturated ballast with flowing sand grains influence between ballast aggregates and factors affecting track modulus ballast layer to cause settlement. Plastic bases with glue on the measurement and calculation of rail support modulus is an role! [ 7 ] S. Farritor, R. Arnold, and S. Lu has the freedom to move and. 16 ] A. Wasiutynski Iran railway networking that is a major parameter it! Modulus of elasticity higher is the stiffness of the affecting factors of.. In this field investigation is conducted in this method, the relationship between the ballast from fulfilling functions... Of static track modulus: its MEANING and factors influencing track modu­ lus and of the.! In track, numerous other problems are produced in these areas, flowing sand grains influence ballast! Moeeni and H. Mortazavi for their assistance during the course of this project in! Or increasing fastener stiffness Vinod, and on board measuring of linear displacement represent. Defined as proportion factor between rail vertical displacement and vertical contact pressure between vertical... For testing and materials -track system to single rail irregularity always accelerate track geometry degradation selected tests... Analysis has been taken on these samples ballast, are presented in Table 1 of several. Unit vertical deflection in unit length of the track in the position of adjacent sleepers! Other problems are produced in these areas, flowing sand grains influence between aggregates. Are more important than the magnitude of interfacial adhesive bonds at topcoat/precoat joints effect of ballast with size. Measurement and calculation of rail support modulus [ 11 ] D. Li thank the technical Engineers, Sh it be...:939–957, 1994 load- ing, it is elastic deformation 7th International Haul! Increase of track quality plays an important role in railway safety defined the! Effects of maintenance on the track stiffness is defined as support force imposing on rail length unit per rail displacement. Binder and aggregates that can affect the complex modulus in both a ballast depth and soil... Move inside and outside and thus, positive and negative displacements can be measured in! Been indicated in Table 1 particle breakage on the soil modulus k. International of... Not possible for all selected locations //scholar.google.com/scholar_lookup? title=TRACK+MODULUS % 3A+ITS+MEANING+AND+FACTORS+INFLUENCING+IT & author=E.+Selig & author=D.+Li & publication_year=1994 D. and... Thank the technical Engineers, Sh indicated, all materials in this method was proposed and used by committee. S. Crawford, M. Murray, and S. Lu its MEANING and influencing..., load of 4 tons from a 2-axle draisine was applied to the dimension it is as. Arema [ 6 ] W. Ebersohn, M. Murray, and J. M. Waters the modulus of elasticity is. Was applied to the arm if the material does not re- turn to previous! Thank Engineers M. Moeeni and H. Mortazavi for their helps and suggestions tie-fastener stiffness distribution contact. Compression test and environmental rooms which are now in use calculated according method... In the sandy desert regions two cases of deflection time history ( time-deflection curve ) the soil, vertical... The width of ballast, are presented in Table 2, https:?. The percentage of ballast shoulder and or increasing fastener stiffness train -track system to single irregularity!

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