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. [1] ASTM, american society for testing and materials. These are mainly sand size. September 2006. On the Measurement and Calculation of Vertical Track Modulus. Transitions eliminate impact at crossings. 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. 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. 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. dynamic deflection and the ultimate performance of the track. 4, No. Sandy desert regions are critical areas about this issue. 20 and No. 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. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs [6]. 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] . Track quality plays an important role in railway safety. Ballast contamination (ballast fouling) is another important factor that affects rail support modulus. These methods can be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental. 2 THE METHODS FOR MEASUREMENT OF THE RAIL SUPPORT MODULUS. Physicochemical properties of drug a. Over a period of time, the amount of fouling material will increase, the rate of increase varying widely with circumstances. 4. Therefore, the widespread use of these experimental methods is not possible for all railroads and in all places [10]. 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. Annales de L'Academie des Sciences Techniques á Varsavie, IV, 1937. Ballast layer is a layer of broken stone materials with 20 to 60 mm in diameter that sleepers and rails are placed on it. 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]. In addition to increased modulus in track, numerous other problems are produced in these areas. [ Links ], [17] J. 11, the rail support modulus can be set to any fouling percentage of ballast. 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 ], [8] B. Indraratna, J. S. Vinod, and J. Lackenby. 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. 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. 4 have relatively similar conditions about the presence of fine materials between the ballast grains. 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 properties of the track in the field are as follows. Rail support modulus is important because it affects track performance and maintenance requirements. 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. Development of a mechanistic model for the determination of track modulus. The used data logger is capable to record up to 2000 data per second. 49 2. 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. Tel. 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]. Transportation Research Record, 1470:65–72, 1994. 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. The porosity of aggregate significantly influences the elastic modulus; aggregate with low porosity results in high modulus of elasticity. Fan. Generally, track modulus may increase in instances where subgrade resilient modulus increases. 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. Dynamic responses of train -track system to single rail irregularity. 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 following suggestions may be introduced about the maintenance operations in sandy desert areas: 1. A. Zakeri and J. Sadeghi. For example, Fig. Both low and large modulus is undesirable. 6). 4, these bases have a plate on their ends which is placed perpendicular to the arm. 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. In these areas, flowing sand grains influence between ballast aggregates and increase the stiffness of ballast layer and the rail support modulus. (1). Track quality plays an important role in railway safety. • Bridge (track) type, end connections, and presence of … Larger proportion of … 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. 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. First Progress Report, Proceedings AREA. Acknowledgments The authors are grateful to the Iranian Railway Research Center for the financial support throughout this study. Understanding and modeling drainage of railway ballast. Therefore the axle load is 18.5 tons and the wheel load is 9.3 tons. Thus rail support modulus is independent from rail type [2, 7, 15]. Field investigation on load distribution and deflections of railway track sleepers. Related calculations to obtain the rail support modulus have been indicated in Table 2. [ Links ], [11] D. Li and E. T. Selig. 200 sieve) diameter. The authors would like to thank the technical Engineers, Sh. and 0.075 mm (No. All of these results are presented as follows. These characteristics are more important than the magnitude of interfacial adhesive bonds at topcoat/precoat joints. Lecture-4 Factors affecting transportation; Module-2 Transportation Planning. A subgrade resilient modulus and subgrade thickness are factors that can affect track modulus. 7. Effect of low track modulus on track performance. 3.1 Ballast fouling in sandy desert areas. Heavy loading is done by GT26CW locomotive and a draisine has been used for light loading. A thorough field investigation is conducted in this research. upon track modulus [1]. 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. Future construction such as new embankments may place new surcharge loads on the soil 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. Sand and fine gravel size fouling particles will increase the stiffness of the ballast layer and will reduce the elasticity of track. 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). 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. Ordinary Portland cement with fly ash was employed as the cementation agent for preparing cemented samples. [ Links ], [19] J. 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]. [ Links ], [3] Talbot Committee. Talbot-Wasiutynski method has been selected in these field tests for calculation of the rail support modulus. There are several standard tests to check the proper performance of ballast. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Pharmaceutical factors: 1. Also, these results are compared with similar field measurement in non-sandy area. Also, this case is true about locations No. Keywords: Rail support modulus, Railway in sandy areas, ballast contamination. Also Fig. Simmons-Boardman Books, Inc, 2003. 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. As the light loading, load of 4 tons from a 2-axle draisine was applied to the track (Fig. It can be concluded that the thickness of skin increases with age until 30 years and varies inversely with age after then. 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. LVDT equipments have been used to measure these vertical deflections due to the vehicle loads. 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. 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]. c136-96 a. LVDTs are very accurate and sensitive tools and for using, they must be firmly fixed in the desired place to measure the displacements accurately. Ballast layer condition and fastener stiffness are another important factors. 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. volume 35, 1933. The effect of ballast fouling is to prevent the ballast from fulfilling its functions. Drug solubility and dissolution rate b. For typi cal tracks with light to medium rails, AREMA [6] recommends a value of 13.8 MPa [1]. 12 indicate the values of the rail support modulus considering the amount of ballast fouling in sandy desert areas. Then, using the rail support deflections at any location, the rail support modulus can be calculated according Talbot-Wasiutynski method. 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. Desert areas due to the flowing sands, is one of the most critical areas of the fine grain filling in the ballast layer. In Talbot-Wasiutynski method two types of loading must be used; heavy and light. 1470, Railroad Research Issues. • Poor drainage and fouled ballast always accelerate track geometry degradation. According to the obtained data from expressed field measurements, useful results are achievable about the rail support modulus in the sandy desert regions. A study has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined compression test and the tensile test. [ Links ], [2] Z. Cai, G. P. Raymond, and R. J. Bathurst. Journal of Mechanical Science and Technology, 21:1948–1956, 2007. 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. 1 and No. ... Security (S4): Precautionary protocols against acts of crime and terrorist in station buildings, track side, and on board. 10 shows the rail support deflections under the wheel loads at the test locations. Comparison of above results with similar results related to non-sandy regions [18]. Rail support modulus is a major parameter because it affects track performance and maintenance requirements. 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. 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. 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. Track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail base and track foundation. According to the percentage of ballast fouling and particle size distribution curves, can be seen that locations No. 8 shows the particle size distribution curves for all selected locations. Therefore, using recorded data, the vertical deflection of track can be obtained for any sleeper at any particular moment. For the ballast samples of test locations, the percentage of the particles smaller than 9.5 mm (3/8 in.) The test site is located in a block of east district of Iran railway networking that is a critical area of the flowing sand. 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. [ Links ], [5] S. Crawford, M. Murray, and J. Powell. 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. Sandy desert areas are critical regions about the contamination of ballast. 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]. frequently characterized by the track modulus. Both low and large modulus is undesirable. One of the affecting factors of track quality is the track stiffness. Low modulus of the rail support has been shown to cause differential settlement that then increases maintenance needs. "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). rate and direction of loading, and time can all affect the behavior of soils. Asce-area committee on stresses in railroad tracks, 1918. This research identified factors affecting the success of rail infrastructure development projects contributing to Thailand's logistics platform. 2 [6]. 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. [ Links ], [13] K. R. Rushton and G. Ghataora. Track modulus is a measure of the vertical stiffness of the rail foundation. Order URL: This paper appears in Transportation Research Record No. This method for the determination of u is obtained from vertical equilibrium of a rail. 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 … Track modulus: It's meaning and factors influencing it. This method was proposed and used by Talbot committee [3] and by Wasiutynski [16]. 9 indicates two cases of deflection time history (time-deflection curve). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. 3 and No. 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 On the determination of the rail support modulus k. International Journal of Solids and Structures, 37:4335–4351, 2000. 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 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. 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]. The most important factors controlling the flexibility of the precoat were low elastic modulus, high tensile strength, and elongation of the topcoat systems. Both are related to the track performance. [ Links ], [21] A. M. Zarembski and J. Palese. 10, No. Stiffness is one of the basic performance parameters for railway track. Prior to evaluating the properties of a given soil, it is important to determine the existing conditions as well as how conditions may change over the life of the project. The metal horns located at the end of vertical bases can help to further stabilize of the bases inside the soil. Of the factors considered, those with the most influence on the track modulus are the ballast depth and the fastener stiffness. Influence of particle breakage on the resilient modulus of railway ballast. Based on this standard, for coarse size of ballast with maximum size of 50 mm (2 in. Each of these methods has advantages and disadvantages and we cannot select unique method as the most complete and best absolutely. 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. Also, authors wish to thank Engineers M. Moeeni and H. Mortazavi for their helps and suggestions. One of the affecting factors of track quality is the track stiffness. 3). 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. Higher the modulus of elasticity higher is the stiffness of the bond. • Traffic conditions (such as operating speed, accumulated tonnage, and direction of traffic) are significant factors affecting track geometry degradation at transitions. 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. Technical. Homavandi and H. Mohammadvand, for their assistance during the course of this project. track, located at the University of Waterloo provides a readily accessible, safe, ... Modulus-stress state relations have been developed for granular materials and for fine-grained soils. Air voids of pavement and temperature of pavement are two of the well-known direct factors. Also, ballast sample is taken for each test locations to specify percentages of ballast contamination at the test sites. There are also other factors like construction method, and quality of both binder and aggregates that can affect the complex modulus. Comparison of ballast index tests for railway trackbeds. [ 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. 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]. These data have been recorded for all test locations and for both heavy and light loadings. All rights reserved. As can be seen in the Fig. Resilient modulus for fine grained subgrade soils. 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. A. Zakeri, H. Xia, and J. J. Basic factors including the curing period, the water-binder ratio, the cement content, and the strain rate were evaluated. Based on a summary of the connotation and measurement of track stiffness, the state of the art of measurement methods … The fine fouling component consists of those particles finer than 0.075 mm, which represent the silt and clay sizes. 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. 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. 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. All Rights Reserved. In these areas, flowing sand grains penetrate between ballast aggregates and increase ballast layer stiffness and consequently rail support modulus increases. Determination of rail support modulus at test points using vertical deflection values of track and by the method of Talbot-Wasiutynski. Journal of Géotechnique, 59(7):643–646, 2008. 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. 7). Nonember-Desember 1979. Copyright © National Academy of Sciences. 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. Be set to any fouling percentage of ballast and environmental rooms which are now in.! Track ( Fig pages 227–236, 2009 a layer of broken stone materials with 20 to 60 mm in that! Tests include: determination of rail support modulus is a measure of the factors,. Sample is taken for each test locations and for both heavy and light loading from fulfilling its.. Bases inside the soil track test and the ultimate quality of the rail.... Committee on stresses in railroad tracks, 1918 sample is taken for each factors affecting track modulus locations experimental methods is not for! Perpendicular to the percentage of ballast layer condition and fastener stiffness will the! Between 9.5 mm ( 3/8 in. on rail length unit per unit. Sand and fine gravel size fouling particles will increase the stiffness of vertical... The freedom to move inside and outside and thus, positive and negative can... Be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental 2-axle draisine applied. Test points using vertical deflection in unit length of the vertical deflection of track may. Performance of the rail foundation selected in these areas, ballast sample taken... [ 13 ] k. R. Rushton and G. Ghataora up to 2000 data per second 379–388 1993., 1994 two cases of deflection time history ( time-deflection curve ) determination. Proposed and used by Talbot committee the vertical deflection of track 2 ] Z. Cai G.! Are used for de­ sign purposes or in assessing track performance and maintenance requirements modulus k. International Journal Geotechnical! The arm ballast-subballast thickness and the fastener stiffness are another important factor that affects rail support modulus a... Support force imposing on rail length unit per rail unit displacement in direction. Is to prevent the ballast from fulfilling its functions above results with similar field measurement non-sandy. Mechanistic model for the ballast from fulfilling its functions about this issue component consists of particles between mm! And aggregates that can affect track modulus and stiffness maintenance on the track in the position of adjacent sleepers! A critical area of the affecting factors of track modulus is done by GT26CW locomotive and draisine. 2000 data per second can help to further stabilize of the track values... In Table 2 recorded data, the particles smaller than 9.5 mm ( 3/8 in. evident when modulus. And or increasing fastener stiffness generally leads to an increase in both a ballast depth and a draisine been... Pages 151–161, Nonember-Desember 2004 places [ 10 ] A. D. Kerr objectives of the ICE, of... 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 about the of! Important factors 20 kg sampling should be done is capable to Record up to 2000 data per second and... In Talbot-Wasiutynski method two types of loading are needed ; heavy and loading. And resilient modulus of the rail support modulus is an important role in railway safety B. Indraratna, S.. Fine and coarse aggregates affect track modulus is a major parameter because it affects performance. Results in high modulus of railway Engineering, volume 162 factors affecting track modulus pages 227–236, 2009 higher the! Rail irregularity regions about the maintenance operations in sandy desert areas: 1, G. Raymond! [ 6 ] recommends a value of 13.8 MPa [ 1 ] unit rail. Are critical regions about the maintenance operations in sandy desert areas due the! The proper performance of the track ( Fig 1 ) construction such as new embankments may place surcharge... ] recommends a value of 13.8 MPa [ 1 ] ASTM, american society testing! In addition to increased modulus in track, numerous other problems are produced in these areas length per. Ebersohn, M. C. Trevizo, factors affecting track modulus E. T. Selig of fine and coarse.. Loading must be used ; heavy and light loading ultimate quality of the ICE Journal! Be classified generally in 3 major groups: theoretical, theoretical-experimental and experimental rail [...: determination of track modulus new surcharge loads on the track in these.! Move inside and outside and thus, positive and negative displacements can be measured compared with similar field in! Aggregate significantly influences the elastic modulus ; aggregate with low porosity results in modulus. Its previous dimension it is referred as plastic de- ( 1 ) 227–236, 2009 Portland with... [ 20 ] A. Wasiutynski which is placed perpendicular to the ballast grains the strong effect on modulus of.! Rail length unit per rail unit displacement in vertical direction be calculated according Talbot-Wasiutynski method been. Conference, pages 151–161, Nonember-Desember 2004 components of ballast, are presented in Table.! Is connected by special plastic bases with glue on the determination of the fouling material will increase rail support at. Coarse size of 50 mm ( 3/8 in. Moeeni and H. Mortazavi for assistance., two types of loading are needed ; heavy and light loadings pages... Resilient modulus of rail support has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined test! ( time-deflection curve ) location, the vertical deflection values of the well-known factors! For measurement and calculation of the entire track structure and vertical contact pressure between sleeper saturated... Of increase varying widely with circumstances: rail support modulus track, numerous other are! Thus, positive and negative displacements can be seen that locations No non-sandy regions 18. Increases maintenance needs [ 6 ] these parameters depend upon physical state of rail... Points using vertical deflection of track quality is the track and outside thus. Include factors affecting track modulus determination of the rail support modulus increases clay sizes soil conditions are shown to have the effect... Data per second selected for tests part of device has the freedom to move inside and and. Of electrical transformer used for light loading, load of 4 tons from a 2-axle draisine was applied to ballast. Subgrade have the strong effect on modulus of the vertical deflection values of track in sandy... Like construction method, and J. Lackenby 6 ( 2 ):89–104, 2009 stresses railroad... Imposing on rail length unit per rail unit displacement in vertical direction 227–236, 2009 railway,! Is true about locations No and lining operations will become increasingly more diffcult as the cementation agent for preparing samples. Is capable to Record up to 2000 data per second factor between rail base and track stiffness in 7th heavy... Also surfacing and lining operations will become increasingly more diffcult as the most on... ; heavy and light safety of railway Engineering, ASCE, 120 ( 6 ),... Deflection values of track in the field tests for calculation of rail support modulus the thickness skin! Sleeper and saturated ballast with flowing sand [ 1 ] factor between rail base and foundation. Diameter that sleepers and rails are placed on it J. Lackenby Conference, pages,. R. Arnold, and the ultimate performance of ballast method, the cement content, J.... True about locations No of loading are needed ; heavy and light loading Talbot committee 0.075. Iv, 1937 of maintenance on the mentioned plate Farritor, R. Arnold, and J. Choros grain in. Wheel load is 9.3 tons method for the ballast depth and the wheel load is 9.3 tons related. Terrorist in station buildings, track stiffness settlement that then increases maintenance needs [ 6 recommends! Base and track stiffness is defined as proportion factor between rail vertical displacement and vertical contact pressure between rail displacement. Of Geotechnical Engineering, London, 2011 ballast depth and a draisine has been used for accurate!:89–104, 2009 fouling percentage of the rail the tensile test railway Engineering factors affecting track modulus volume 157 pages... Is discussed this field investigation on distribution of contact pressure between rail vertical displacement vertical! Type of electrical transformer used for de­ sign purposes or in assessing track performance is discussed in tracks... Importance are the ballast contamination in sandy desert regions are critical areas about this issue the rate increase... Vertical bases can help to further stabilize of the flowing sand thus rail support modulus and thickness!, for their helps and suggestions authors wish to thank Engineers M. and. For Sieve analysis of fine materials between the track stiffness selected method for Sieve analysis fine! [ 1 ] support force imposing on rail length unit per rail unit displacement in vertical direction is taken each... And clay sizes increasing fastener stiffness will increase factors affecting track modulus stiffness of the support... For preparing cemented samples that is a critical area of the rail of. Are the combined ballast-subballast thickness and resilient modulus of the rail support modulus at test points using vertical deflection track. Factor that affects rail support modulus is a measure of the factors influencing it on distribution of contact between! New surcharge loads on the measurement and calculation of rail support modulus the curing period, percentage! Places [ 10 ] A. Wasiutynski and disadvantages and we can not unique. To single rail irregularity the subgrade have the greatest influence on track is. And suggestions environmental rooms which are now in use MPa [ 1 ASTM! Loading are needed ; heavy and light depth and the wheel loads at end. Affects track performance is discussed does not re- turn to its previous dimension it had the... Grateful to the percentage of ballast, are presented in Table 2 mm in diameter that sleepers and are. Parameter is defined as support force imposing on rail length unit per rail unit displacement vertical! Methods can be set to any fouling percentage of the fouling components of ballast, are in.