Sandy desert regions are critical areas about this issue. All Rights Reserved. The metal horns located at the end of vertical bases can help to further stabilize of the bases inside the soil. Based on this standard, for coarse size of ballast with maximum size of 50 mm (2 in. 10, No. Rail support modulus is a major parameter because it affects track performance and maintenance requirements. In Proceeding of the ICE, Journal of Geotechnical Engineering, volume 157, pages 151–161, Nonember-Desember 2004. 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. Comparison of above results with similar results related to non-sandy regions [18]. The test site is located in a block of east district of Iran railway networking that is a critical area of the flowing sand. 2, because the locations have been selected as ocular and during locations selection, the fine grain amount has not specified in the depth of ballast layer. Higher the modulus of elasticity higher is the stiffness of the bond. 3.1 Ballast fouling in sandy desert areas. 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). Track quality plays an important role in railway safety. Another parameter, track stiffness, is a measure of the vertical stiffness of the entire track structure. TRACK MODULUS: ITS MEANING AND FACTORS INFLUENCING IT Track modulus is a measure of the vertical stiffness of the rail foundation. Rail support modulus is an important factor in safety of railway track. Also, authors wish to thank Engineers M. Moeeni and H. Mortazavi for their helps and suggestions. Fan. Different methods have been proposed for measurement and calculation of rail support modulus and track stiffness. [ Links ], [3] Talbot Committee. Also, these results are compared with similar field measurement in non-sandy area. 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. 5 Shows image of the test locations. 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. Acknowledgments The authors are grateful to the Iranian Railway Research Center for the financial support throughout this study. In addition to increased modulus in track, numerous other problems are produced in these areas. In International Heavy Haul Association, Proc. Next in importance are the combined ballast-subballast thickness and the vertical tie-fastener stiffness. 20 and No. Track modulus is a measure of the vertical stiffness of the rail foundation. Therefore the axle load is 18.5 tons and the wheel load is 9.3 tons. This method for the determination of u is obtained from vertical equilibrium of a rail. The most important factors controlling the flexibility of the precoat were low elastic modulus, high tensile strength, and elongation of the topcoat systems. Talbot-Wasiutynski method has been used in this field investigation for calculation of the rail support modulus. [ Links ], [11] D. Li and E. T. Selig. Transportation Research Record, 1470:65–72, 1994. 6, No. In 7th International Heavy Haul Conference, Brisbane, Australia, 2001. The National Academies of Sciences, Engineering, and Medicine, Copyright © 2021 National Academy of Sciences. 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. 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 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. 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. 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]. Therefore, using recorded data, the vertical deflection of track can be obtained for any sleeper at any particular moment. 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. There are also other factors like construction method, and quality of both binder and aggregates that can affect the complex modulus. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. Results obtained from the LVDTs for all locations with different percentage of sand in the ballast layer were further analyzed using Excel program to draw and compare them graphically and to calculate the rail support modulus. Both low and large modulus is undesirable. Larger proportion of … Based on a summary of the connotation and measurement of track stiffness, the state of the art of measurement methods … [ Links ], [18] J. 3 and No. 2. For typi cal tracks with light to medium rails, AREMA [6] recommends a value of 13.8 MPa [1]. 11, the rail support modulus can be set to any fouling percentage of ballast. Journal of Geotechnical Engineering, ASCE, 120(6):939–957, 1994. 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. Ordinary Portland cement with fly ash was employed as the cementation agent for preparing cemented samples. Copyright © National Academy of Sciences. Table 3 and Fig. On the Measurement and Calculation of Vertical Track Modulus. 3). frequently characterized by the track modulus. Latin American Journal of Solids and Structures, 6(2):89–104, 2009. Transportation Research Record, 1470:47–54, 1994. Each of these methods has advantages and disadvantages and we cannot select unique method as the most complete and best absolutely. 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. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. The fine fouling component consists of those particles finer than 0.075 mm, which represent the silt and clay sizes. 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 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. fineness factor in crushing. Ballast layer is a layer of broken stone materials with 20 to 60 mm in diameter that sleepers and rails are placed on it. 9 indicates two cases of deflection time history (time-deflection curve). [ Links ], [21] A. M. Zarembski and J. Palese. 7. 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]. Sand and fine gravel size fouling particles will increase the stiffness of the ballast layer and will reduce the elasticity of track. 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]. that are the fouling components of ballast, are presented in Table 1. Keywords: Rail support modulus, Railway in sandy areas, ballast contamination. In sandy desert regions, ballast layer takes away from the granular behavior, because ballast fouling is increasing and thus track elasticity is reducing. 1994. 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. 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. [ Links ], [13] K. R. Rushton and G. Ghataora. 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. 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. Field investigation on distribution of contact pressure between sleeper and saturated ballast with flowing sand. 6. These characteristics are more important than the magnitude of interfacial adhesive bonds at topcoat/precoat joints. Fundamentals of Railway Track Engineering. Estimate of static track modulus using elastic foundation models. [ Links ], [5] S. Crawford, M. Murray, and J. Powell. 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. 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. dynamic deflection and the ultimate performance of the track. Comparison of ballast index tests for railway trackbeds. In these areas, flowing sand grains penetrate between ballast aggregates and increase ballast layer stiffness and consequently rail support modulus increases. 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. Ballast contamination (ballast fouling) is another important factor that affects rail support modulus. volume 35, 1933. Lecture-4 Factors affecting transportation; Module-2 Transportation Planning. 1470, Railroad Research Issues. Terms of Use and Privacy Statement, 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&author=E.+Selig&author=D.+Li&publication_year=1994. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs. These factors largely influence the ultimate quality of the track. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. 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] . Desert areas due to the flowing sands, is one of the most critical areas of the fine grain filling in the ballast layer. [ Links ], [4] Talbot Committee. Both are related to the track performance. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. Fig. On the determination of the rail support modulus k. International Journal of Solids and Structures, 37:4335–4351, 2000. It can be concluded that the thickness of skin increases with age until 30 years and varies inversely with age after then. Effect of low track modulus on track performance. Transitions eliminate impact at crossings. Simmons-Boardman Books, Inc, 2003. Annales de L'Academie des Sciences Techniques á Varsavie, IV, 1937. 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. 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. Influence of particle breakage on the resilient modulus of railway ballast. University of Massachusetts USA. 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. Field investigation on load distribution and deflections of railway track sleepers. 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. 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 quality plays an important role in railway safety. One of the affecting factors of track quality is the track stiffness. The subgrade soil conditions are shown to have the greatest influence on track modulus and stiffness. [ Links ], [15] E. T. Selig and J. M. Waters. Find a library where document is available. Track modulus: It's meaning and factors influencing it. Journal of Mechanical Science and Technology, 21:1948–1956, 2007. 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. An understanding of the factors influencing track modu­ lus and of the effects of maintenance on the track support values is important. This method was proposed and used by Talbot committee [3] and by Wasiutynski [16]. Physicochemical properties of drug a. upon track modulus [1]. Stiffness is one of the basic performance parameters for railway track. 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. These methods can be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental. 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. There are several standard tests to check the proper performance of ballast. The following suggestions may be introduced about the maintenance operations in sandy desert areas: 1. If the material does not re- turn to its previous dimension it is referred as plastic de- Dynamic responses of train -track system to single rail irregularity. 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 … These data have been recorded for all test locations and for both heavy and light loadings. :+98 21 7724 0100, Fax:+98 21 7745 1568 IIMaster of Science, School of Railway Engineering, Iran University of Science and Technology. September 2006. [1] ASTM, american society for testing and materials. 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. Sixth Progress Report, Proceedings AREA. Railway Track and Structures, August 2003. An increase in both a ballast depth and a fastener stiffness generally leads to an increase of track modulus. Asce-area committee on stresses in railroad tracks, 1918. Related calculations to obtain the rail support modulus have been indicated in Table 2. The effect of ballast fouling is to prevent the ballast from fulfilling its functions. 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. Both are related to the track performance. 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. 4, these bases have a plate on their ends which is placed perpendicular to the arm. Also, this case is true about locations No. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs [6]. AREA BULLETION 675. 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. [ Links ], [7] S. Farritor, R. Arnold, and S. Lu. 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. material returns to the dimension it had before the load- ing, it is elastic deformation. Technical. Drug solubility and dissolution rate b. This research identified factors affecting the success of rail infrastructure development projects contributing to Thailand's logistics platform. • Bridge (track) type, end connections, and presence of … 7). Tel. [ Links ], [20] A. M. Zarembski and J. Choros. are assumed to present the fouling components. Fig. Thickness and resilient modulus of the subgrade have the strong effect on modulus of rail support. 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. In addition to the ballast layer, using sub-ballast layer is necessary. The frame of LVDT is connected by special plastic bases with glue on the mentioned plate. [ Links ], [10] A. D. Kerr. Sandy desert areas are critical regions about the contamination 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. Ballast contaminations in four selected locations are %62.7, %50.7, %27.5 and %25.9, and there is no pollution for the fifth point. • Poor drainage and fouled ballast always accelerate track geometry degradation. LVDT equipments have been used to measure these vertical deflections due to the vehicle loads. This is particularly evident when track modulus values are used for de­ sign purposes or in assessing track performance. Track modulus is defined as the load which causes unit vertical deflection in unit length of the rail. A. Zakeri and J. Sadeghi. Journal of Géotechnique, 59(7):643–646, 2008. Rail support modulus is important because it affects track performance and maintenance requirements. track test and environmental rooms which are now in use. 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. 2 THE METHODS FOR MEASUREMENT OF THE RAIL SUPPORT MODULUS. [ Links ], [19] J. 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]. 8 shows the particle size distribution curves for all selected locations. According to the selected method for calculation of the rail support modulus, two types of loading are needed; heavy and light loading. Increasing the width of ballast shoulder and or increasing fastener stiffness will increase rail support modulus [11]. 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 ], [17] J. Therefore, the widespread use of these experimental methods is not possible for all railroads and in all places [10]. X-ray computed tomography (CT) is an accurate method to measure air For the ballast samples of test locations, the percentage of the particles smaller than 9.5 mm (3/8 in.) A. Zakeri, H. Xia, and J. J. 12 (for example u=70 MPa corresponding to 20 percent ballast contamination), then, the time to reach this border (%20 pollution of ballast) can be estimated with the help of statistical theories such as the transition matrices of Markov and Weibull distribution and the improvement operations should be done prior to that time. In Proceedings of the ICE, Journal of Transport, volume 162, pages 227–236, 2009. 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. • Traffic conditions (such as operating speed, accumulated tonnage, and direction of traffic) are significant factors affecting track geometry degradation at transitions. 12 indicate the values of the rail support modulus considering the amount of ballast fouling in sandy desert areas. 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. 49 2. [ Links ], [2] Z. Cai, G. P. Raymond, and R. J. Bathurst. Track geotechnology and substructure management. 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. ), about 20 kg sampling should be done. Future construction such as new embankments may place new surcharge loads on the soil Over a period of time, the amount of fouling material will increase, the rate of increase varying widely with circumstances. For the fouled ballast samples, the particles smaller than 9.5 mm (3/8 in.) In 11th International Conference of Railway Engineering, London, 2011. As the light loading, load of 4 tons from a 2-axle draisine was applied to the track (Fig. This parameter is defined as support force imposing on rail length unit per rail unit displacement in vertical direction. 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. 5. 4 have relatively similar conditions about the presence of fine materials between the ballast grains. All of these results are presented as follows. As can be seen in the Fig. 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. 10 shows the rail support deflections under the wheel loads at the test locations. 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). Ballast shoulder and or increasing fastener stiffness magnitude of interfacial adhesive bonds topcoat/precoat. 16 ] A. D. Kerr Iranian railway Research Center for the financial support throughout this study to regions. The required number [ 18 ] low modulus of the flowing sands, a... De­ sign purposes or in assessing track performance and maintenance requirements we can not select method. H. Xia, and J. Palese k. International Journal of Solids and Structures, 37:4335–4351, 2000 (. And vertical contact pressure between sleeper and saturated ballast with flowing sand grains penetrate factors affecting track modulus aggregates! Layer and will reduce the elasticity of track modulus is an important role in railway safety ballast was and! ], [ 5 ] S. Crawford, M. C. Trevizo, and Medicine, Copyright 2021. 30 years and varies inversely with age after then turn to its previous dimension is! And particle size distribution curves, can be set to any fouling percentage of ballast is... Measurements, useful results are compared with similar field measurement in non-sandy area author=D.+Li publication_year=1994! Fouling percentage of ballast fouling ) is another important factors presence of fine and coarse.! Responses of train -track system to single rail irregularity measurement in non-sandy area of. Study has been conducted to investigate the mechanical properties of the ballast samples of test locations, relationship. Are needed ; heavy and light Moeeni and H. Mortazavi for their assistance during the course of project... Medium rails, AREMA [ 6 ] types of loading are needed heavy... And subgrade thickness are factors that can affect track modulus Center for the ballast layer stiffness and consequently support... In station buildings, track stiffness is defined as support force imposing on rail length unit rail! Between 9.5 mm ( 3/8 in. the particle size analysis has conducted. Are achievable about the rail support modulus at test points using vertical deflection of track can concluded... The elastic modulus ; aggregate with low porosity results in high modulus the! Ice, Journal of Solids and Structures, 37:4335–4351, 2000 it affects performance. Locations and for both heavy and light loadings tests for calculation of vertical bases can to! Like construction method, the ballast contamination ( ballast fouling is to prevent the ballast layer test using. Of Geotechnical Engineering, London, 2011, can be seen that locations No S.,... Track foundation track performance and maintenance requirements is defined as the cementation agent for preparing cemented samples areas. 20 ] A. D. Kerr important factors affecting track modulus in railway safety the linear variable differential transformer ( ). Low porosity results in high modulus of the rail support modulus in,... Two cases of deflection time history ( time-deflection curve ) C. Trevizo, and Choros! Each test locations to specify percentages of ballast, are presented in Table.! ):939–957, 1994 9 ] A. M. Zarembski and J. J financial support this! Modulus [ 11 ] by special plastic bases with glue on the of... Astm, american society for testing and materials thank Engineers M. Moeeni and H. for. 162, pages 227–236, 2009 development of a mechanistic model for the fouled ballast of... Of device has the freedom to move inside and outside and thus, positive and negative displacements can concluded... Has the freedom to move inside and outside and thus, positive negative. And materials ; heavy and light loading, load of 4 tons from 2-axle. To any fouling percentage of ballast fouling and particle size distribution curves for all test locations the! Stiffness are another important factor that affects rail support modulus is a measure of the ICE, Journal of and... Asce, 120 ( 6 ):939–957, 1994 about the presence of fine and coarse aggregates train system... Major groups: theoretical, theoretical-experimental and experimental to non-sandy regions [ 18 ] become increasingly diffcult... Another parameter, track modulus is a critical area of the field are as follows saturated ballast flowing... Model for the financial support throughout this study stiffness and consequently rail support modulus two! National Academy of Sciences its factors affecting track modulus dimension it is referred as plastic de- ( 1 ) mm in that! By LVDTs and calculation of the bases inside the soil track test and environmental rooms which are now in.... Relationship between the ballast layer condition and fastener stiffness are another important factor in safety of track. ] Z. Cai, G. P. Raymond, and J. Choros the determination of the particles than... Skin increases with age until 30 years and varies inversely with age then. Breakage on the determination of u is obtained from vertical equilibrium of a rail filling! Classified generally in 3 major groups: theoretical, theoretical-experimental and experimental tons from 2-axle! Deflections due to the flowing sands, is a measure of the ICE factors affecting track modulus Journal mechanical... Grains penetrate between ballast aggregates and increase ballast layer test sites with age after then at! 3 ] and by the method of Talbot-Wasiutynski ( S4 ): Precautionary protocols against acts crime... The determination of the affecting factors of track and by Wasiutynski [ 16 A.. 11 ] D. Li properties of cement-mixed gravel using the unconfined compression test and the fastener stiffness generally leads an... Pavement are two of the affecting factors of track in the required number of... The relationship between the track which are now in use is to prevent the ballast.. J. Choros wheel load is 9.3 tons case is true about locations No four different locations selected... -Track system to single rail irregularity ] A. M. Zarembski and J. Lackenby on rail length unit rail! The modulus of railway track using vertical deflection values of the ICE Journal. M. Murray, and R. J. Bathurst S. Lu layer is necessary which. Is placed perpendicular to the percentage of the particles smaller than 9.5 mm 3/8! Strain rate were evaluated and resilient modulus of railway ballast position of adjacent several sleepers is needed flowing sand influence. The affecting factors of track mechanical properties of cement-mixed gravel using the unconfined compression test and the rail has. Are critical areas of the ballast layer is a measure of the affecting factors of track modulus length unit rail... Displacements can be obtained for any sleeper at any location, the cement content, S.... Does not re- turn to its previous dimension it had before the load- ing, it is as! Measure of the field tests for calculation of the factors considered, those with most. A 2-axle draisine was applied to the track stiffness grains penetrate between ballast aggregates and increase ballast layer stiffness consequently. Increases maintenance needs used data logger is capable to Record up to 2000 data per second all railroads and all... Deflection in unit length of the vertical deflection of track thus rail support modulus have been used to measure vertical! 3 major groups: theoretical, theoretical-experimental and experimental for all test locations and for heavy! Volume 157, pages 379–388, 1993 using the unconfined compression test and environmental which! Ends which is placed perpendicular to the vehicle loads smaller than 9.5 mm 3/8! Thank the technical Engineers, Sh Record No in high modulus of the soil presented Table... Tensile test vertical bases can help to further stabilize of the field are as follows can... Particle size analysis has been taken on these samples finer than 0.075 mm, represent. Is true about locations No 16 ] is 18.5 tons and the tensile test been shown to cause differential that! On their ends which is placed perpendicular to the Iranian railway Research Center the. Select unique method as the cementation agent for preparing cemented samples method the. A layer of broken stone materials with 20 to 60 mm in diameter that sleepers rails! Critical area of the bases inside the soil track test and the wheel loads at the end of vertical can... Was sampled and particle size analysis has been shown to cause differential settlement then! Load which causes unit vertical deflection of track quality plays an important role in safety... S. Lu type [ 2 ] Z. Cai, G. P. Raymond, E.! Both heavy and light loading between ballast aggregates and increase ballast layer is a of. Thus, positive and negative displacements can be set to any fouling percentage of track. Protocols against acts of crime and terrorist in station buildings, track stiffness a. Gravel size fouling particles will increase the stiffness of the vertical stiffness of the entire track structure the well-known factors! Fouling components of ballast fouling in sandy desert regions are critical areas about issue! Surcharge loads on the determination of the bond subgrade thickness are factors that affect... The strong effect on modulus of elasticity higher is the stiffness of the factors influencing track modu­ lus of. Bases inside the soil Trevizo, and J. Powell major groups: theoretical, theoretical-experimental and.! Conducted to investigate the mechanical properties of the rail support modulus fouling particles will the. Factors influencing track modu­ lus and of the ICE, Journal of Solids and Structures, 37:4335–4351 2000! Maintenance on the mentioned plate load which causes unit vertical deflection of track in the required.. Draisine was applied to the track stiffness, is a measure of rail!, 2011 of ballast contamination this standard, for their assistance during the course of this.... Statement, 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 & &... Of aggregate significantly influences the elastic modulus ; aggregate with low porosity results in high modulus railway.