Road vehicles generally cannot achieve an acceptable compromise between stability and efficiency with a fixed braking distribution (X1/X2 = constant), so in order to improve the braking efficiency over a greater range of vehicle loading and usage conditions, the braking ratio X1/X2 needs to be designed to be variable. Friction Coefficient for Concrete Cast on Soil (reference 4) Friction. Therefore, railway traction and braking theory use the term “adhesion” instead of “static friction” when analyzing the wheel/rail longitudinal force. Load carried by steel = 0.9 × 1000 tons = 900 tons, Allowable steel compressive strength = 0.5 × 36,000 = 18,000 psi. 17). Shunting operation conditions in the station. Control cycles of the ABS with hydraulic brakes. Step 5: find the end bearing (Qbase) and skin friction (Fskin) within the rock mass. In the figure, black circles show all the values obtained in the experiments at 50 °C while white circles show all those at water 5 °C; moreover, solid lines show the curve fitted lines of the maximum traction coefficients at the two different water temperatures. Ruwan Rajapakse, in Pile Design and Construction Rules of Thumb (Second Edition), 2016. Table 2.1. The total buried resistance … The control cycles of a simple ABS are shown in Fig. In some locomotive design work, the reciprocal of the friction factor, called the factor of adhesion, is used. The values of this coefficient are introduced into the program employing the following graph taken from M.J. Tomlinson: Pile Design and Construction Practice. It can be identified that the maximum traction coefficient (i.e. sand. This value is smaller than 30 in. It is clearly identified that the maximum traction coefficient in the case of the larger surface roughness is greater than that in the case of the smaller one. Running through such cycles, the wheel rotational speed is kept in an area where the longitudinal wheel slip sL is close to that of the maximum friction coefficient. Unconfined Compressive Strength, S uc, can be determined in the laboratory using the Triaxial Test or the Unconfined Compressive Strength Test. Two-dimensional simulation demonstrating the Monte Carlo step algorithm. adhesion coefficient) and rolling speed for two kinds of surface roughness (rms. where Pμ is the locomotive (EMU) adhesive mass (t) (adhesive mass of locomotive commonly used are shown in Tables 2.1 and 2.2; the masses of EMUs are shown in Table 2.5); g is the acceleration of gravity (m/s2); and μj is the computational adhesion coefficient between wheel and rail. 26.39. To determine the coefficient of friction and the specific adhesion, the soil slipping resistance should be assessed at several different values of the specific pressure between the slipping surfaces. Clean gravel, gravel--sand mixtures, coarse. Cohesion due to adhesion and interlocking of soil particles, 1 Compaction is soil compression and densification under anisotropic stresses . Recent locomotive models, through better control of wheel slip, offer adhesion potentials of 22%–24% or more. Table of Ultimate Friction Factors for Dissimilar Materials; Adhesion of Soil; Straight Back of the Wall; Analysis of Walls. One of the major mechanical properties of clay is the adhesion factor which reflects the ratio between the cohesive and adhesive strength of clay under different water content. Introduction Soil sliding resistance is made up of friction and adhesion forces that are brought about between the soil and material interface. Friction angle of soil backfill is 35° and adhesion coefficient between concrete and soil is 0.3. 26.40. End bearing ratio (n) is defined as the ratio between the end bearing load of the rock mass (Qbase) and the total resistive force mobilized (Qbase + Fskin) within the rock mass. Coefficient, f. Mass concrete on the following foundation. After this heating process, the friction coefficient increased from 0.5 to about 5.0. 26.42. At first the longitudinal friction coefficient μL(sL) increases as well, building up the friction torque TWL, which narrows the torque difference. Thus: σv’ = 5(120) + 5(120-62.4) = 888 psf Calculating the Lateral Earth Pressure The experimental formula shows the relationship between the computational adhesion coefficient and the operating speed of train under normal adhesive condition. Table 11.5. In Fig. The friction or adhesion factor represents the percentage of locomotive weight on the drivers that is available as effective tractive effort. Maximum starting grade iq(max) is calculated according to Eq. Kd or Kf = Concentration of chemical in soil/Concentration of chemical substance in water Total skin friction = π × 30 × L × 150 lbs (“L” should be in inches). Alteration of soil slipping coefficient has an alternative hyperbolic regress. Total perimeter of the caisson = π × (diameter) × (length) = π × D × L. Total skin friction = π × 30 × L × unit skin friction of rock (in this case 150 psi). By continuing you agree to the use of cookies. This can be overcome by adding ballast to the locomotive with an overweight flame or blocks of concrete. Typically, a factor of safety of 2.0 or more is required. According to operation practice in China, station operation safety cannot be ensured in the station on the grade of 6‰, while that can be ensured in a station on the grade of 2.5‰. Thus: Hence the dynamic component of lateral force: This is equivalent to a ‘damper’ with rate proportional to the slope of the creep curve. In the event of an electrical functional failure that only affects the ABS operation, a mean fully developed deceleration (MFDD; see Chapter 8) > 5.15 m/s2 is required (equivalent to a rate of braking of z = 0.525). Amontons's Laws of Dry Friction. Maximum Grade Preventing Runaway of a High-Speed Train. The grade preventing runaway of the train is then. With the exception of compaction and cementation, other components of cohesion generally have less influence on generation of soil cohesion in engineering practice. Figure 22.2 shows cantilever wall and forces. Tractive Performance Parameters of Diesel Locomotive. Hence, ultimate unit skin friction (f) = 0.5 × 24,000 = 12,000 psf. Step 3: compute the load carried by concrete. standard deviation of roughness, was adopted and measured by means of a stylus profiler along the axial direction of the rail disc. Note: it is assumed that allowable skin friction within soil is fully mobilized. Considering this computational aspect, significant improvements in simulation performance may be accomplished by merely neglecting to maintain a transient history of the system energy. Soil Properties and their Correlations eo o ael ae a ee eley. It is very difficult to measure the value of sc at the contact interface shown in Fig. Before the experiments, the surfaces of the wheel and rail discs were finished with abrasive paper # 80 and # 800, respectively. Engineers should refer to local building codes for the relevant factor of safety values). The braking distribution specified as X1/X2 = 70/30 gives reasonably good braking efficiency between 0.40 ≤ z ≤ 0.80 for the DoW vehicle, and between 0.50 ≤ z ≤ 0.95 for the GVW vehicle. has acquired two connotations. If two grade segments are designed in the starting scope of the train, it shall be considered that the average conversion grade within the train length shall be no greater than the maximum starting grade when the train is located at most unfavorable position. Block diagram of torque balance at wheel base. Higher adhesion permits more tonnage per locomotive unit. In addition to the above control cycles, the braking pressure is therefore decreased when the rotational equivalent wheel speed is. Under the single side adhesion test, the tested side contacted to the soil reservoir and moved with a constant velocity. However, the operation practice shows that runaway exists in coupling vehicle in the existing station with the grade of 1.5‰ of station site. F = Adhesion coefficient × total weight of concrete and soil. Overturning of the retaining wall occurs around point A in the retaining wall (Figure 22.2). Some engineer neglected the adhesion factor, some engineer calculate this with reduction factor.. RE: Adhesion between concrete and soil Mccoy (Geotechnical) 7 Jun 12 05:36. Therefore, while the wheel is rolling on the rail, there is inevitably a longitudinal and transverse sliding at the same time. km/h. The values of this coefficient are introduced into the program employing the following graph taken from M.J. Tomlinson: Pile Design and Construction Practice. 62.4 pcf). W was found to be 372 kN. The longitudinal force between the wheel and rail changes into the sliding friction force; its value is much smaller than adhesive force. Adhesion Coefficient. Relationship between maximum traction coefficient and rolling speed at different water temperatures. Design the caisson so that 95% of the load is carried by skin friction. On the basis of this opinion, by the method of least … 3.7 concerning the effects of adsorbed gases on adhesion. Service braking shall be considered when a high-speed train stops in the station, and the corresponding adhesion coefficient is 0.02–0.06. A slightly moist rail has a low adhesion value (the film of grease usually found on a rail head is spread over the tread surface by the moisture). 26.41. M. Ishida, in Wheel–Rail Interface Handbook, 2009. Cohesive soils are clay type soils. Load carried by concrete = concrete area × 750 psi = 605.8 × 750 lbs = 227.6 tons, Load carried by steel = 900 tons (computed earlier), Total capacity of the caisson = 900 + 227.6 = 1127.6 tons > 1000 tons. Pure hydrogen or pure nitrogen had little effect on friction in similar experiments. Assume a diameter of 30 in. (fallowable) = 12,000/3.0 = 4,000 psf = 2 tsf. Fallowable is less than the skin friction generated. 26.38. The rotational equivalent wheel speeds vRij are measured and differentiated to give the wheel accelerations υ.Rij. The adhesion coefficient η in the figure is defined by. In the case of gale, vibration, or collision, vehicles equipped with rolling bearings may run away when being parked in the station site whose grade exceeds that prevents runaway. Swiss Standard SN 670 010b, Characteristic Coefficients of soils, Association of Swiss Road and Traffic Engineers; JON W. KOLOSKI, SIGMUND D. SCHWARZ, and DONALD W. TUBBS, Geotechnical Properties of Geologic Materials, Engineering Geology in Washington, Volume 1, Washington Division of Geology and Earth Resources Bulletin 78, 1989, Link; Carter, M. and Bentley, S. (1991). The station site shall be set on the near-level grade to ensure the convenience and safety of station operation. Experimental formulae for computational adhesion coefficient μj of all kinds of locomotive are listed as follows: where V is the running speed, in kilometers per hour. To achieve the ‘ideal’ braking distribution through a variable braking ratio, the braking distribution must be continuously adjustable to match the dynamic weight distribution for all values of z. Equations (3.2) and (3.3) showed that for a vehicle decelerating at a rate of braking z: The variable front to rear braking ratio for a two-axle, four-wheel rigid vehicle such as a passenger car is defined as X1var/X2var, and this would ensure that the front and rear wheels of the vehicle lock simultaneously under all conditions of loading and usage. In fact, as there are wheel and rail deformations under the action of massive pressure, wheel and rail are not contacted at a point, there is no ideal instantaneous rotation center, and wheel tread is conical or worn profiled, combined with inevitably impact and various vibrations during the operation process. Since the maximum rate of braking z cannot exceed the coefficient of adhesion k, this means that this vehicle would have reasonably good braking efficiency under higher deceleration conditions on good road surfaces. Thus, the loop becomes unstable, resulting in the abscence of control and, in extremely high rotational wheel deccelerations, blocking of the wheel. Soil-Geogrid Friction Coefficients 1: Introduction: In design and use the interaction coefficients between soil reinforcement materials and the fill around them are critical. Figure 22.5. The, Geotechnical Engineering Calculations and Rules of Thumb (Second Edition), . Allowable concrete compressive strength = 0.25 × ultimate compressive strength = 0.25 × 3000 = 750 psi. The adhesion and external friction angle increased with increasing … By having the adsorption of O2 or air, η drops to zero after the exposure of about 10 Pa s or more. Measurement of the adhesive force in the direction normal to the interface gives more sensitive and reliable values for the estimation of sc under the effects of adsorbed gases and/or oxides. Trucks designed to maintain a more nearly equal weight on each axle also help. The skin friction is developed along the perimeter of the caisson. Adhesion is a function of the friction at the contact point of wheel/rail—that is, effective tractive effort is the production of the total weight on the drivers multiplied by the coefficient of friction between wheel and rail. This option displays only when you select American Lifelines Alliance in the Soil Model Type list and Clay as the Soil Classification. The approach of studying the behaviour in the frequency domain, by linearizing the frictional behaviour, was first adopted by Rudd [9.1]. without ABS or EBD (see Chapter 6). The front wheels of a vehicle are independently controlled, whereas the rear wheels jointly receive the lower braking pressure. It is clearly observed in the figure that the fresh fracture surfaces of copper adheres very strongly and gives a value around η = 0.8. For the mixed passenger and freight line: irul = 6‰, DF4B-type locomotive selected, (Fs = 442.2 kN, P = 138 t, LLoc = 21.2 m), G = 3870 t, train length = 700 m. The plane and profile of a certain passing station are shown in Fig. for the concrete caisson. The wheel rotational equivalent velocity vR (after the integrator in Fig. A complication is that the adhesion coefficient k for the different wheels may not be the same because of different types or makes of tyre, wear, normal forces, and inflation pressure, etc. In this algorithm, Δr is a previously allocated array of relative indices to a neighborhood N(r) of lattice site r. The function draw_a_source(L) returns a randomly selected index in L, draw_a_target(r) returns a randomly selected site in N(r), and rand() returns a uniformly distributed number in [0, 1]. However, the consecutive grades with a gradient of more than 6‰ shall not be arranged for the adjacent two stations. Its definition is mainly derived from the Mohr-Coulomb failure criterion and it is used to describe the non-frictional part of the shear resistance which is independent of the normal stress. The anti-skid braking system (ABS) aims to minimize the braking distance while retaining steerability during braking. hole. Fig. ... adhesion coefficients vary from the type of reinforcement (geotextile, geogrid, etc.) Consequently, the effect of surface roughness on adhesion coefficient under wet conditions is significant. if i'm not wrong, adhesion only consider when foundation support by cohessive soil.. where V is the running speed in kilometers per hour. 3.46. In this procedure, composite nature of the section is ignored. From Table 11.5, for L/a of 4 and Er/Ec of 0.5, end bearing ratio (n) = 0.12. where Fs is the starting traction of locomotive (N); r ′s is the unit starting resistance of locomotive, taking as 50 N/t for electric and diesel locomotives; and r ″s is the unit starting resistance of freight train, calculated according to Eqs. Nismo vam mogli poslati linka na vaš email. Step 10: Find the location of the resultant; The center of gravity of the retaining wall and backfill is 2.09 ft. from point A. Figure 3.17 shows a graph of braking efficiency against adhesion coefficient k for the example vehicle. Surface roughness profiles of the rail disc before the experiments. Braking efficiency is a measure of the use which a vehicle’s braking system is able to make of the available coefficient of adhesion. Static Friction Coefficients. braking pressure is decreased (phase 3). Common values of the adhesion of soil a Prova il Software GEO5. Figure 2: Example of a stress/strain isochronous curves graph. hole. Sirong Yi, in Principles of Railway Location and Design, 2018. Ws = Weight of soil sitting on the retaining wall = (2 × 6) × 18 = 216 kN, W1 = Weight of concrete stem = (0.5 × 6) × 24 = 72 kN, W2 = Weight of concrete base = (1 × 3.5) × 24 = 84 kN, Ha = Horizontal force due to active soil pressure = (Kaγ H) H/2, Hp = Horizontal force due to passive soil pressure = (Kpγ H) H/2, F = Force due to friction between base and soil, F = Adhesion coefficient × total weight of concrete and soil, Resisting force = Hp + F = 33.2 + 111.6 = 144.8 kN, Factor of safety against sliding = 144.8/119.5 = 1.21. Figure 26.39 shows the relationship between the maximum traction coefficient (i.e. In soil physics, BA VER (2), for example, defines it as "the. T.J. Sego, ... A. Tovar, in Numerical Methods and Advanced Simulation in Biomechanics and Biological Processes, 2018. The test results revealed that soil cohesion was decreased, and adhesion was increased after 16.7% moisture content. 3.8. η ≤ 1.0. Hence the corresponding maximum no runaway speed is. 0.45 to 0.55. When the resultant force is acting at the middle third of the base, there will not be tension (Figure 22.3). 19. Therefore, trains can safely stop on the steep grade due to the high braking performance of high-speed EMUs. The drivers will slip at speeds above the limiting adhesion speed and when starting. Taking the constant development of industry and agriculture along the line into consideration, the coupling and uncoupling operation may be available at one of these two adjacent stations at least for the convenience of local transport in future. This is illustrated below for the example vehicle specified in Table 3.1. Before the implementation of ABS on passenger cars and light vans, the UN Legislation required that for all states of load of the vehicle, the adhesion utilisation curve of the rear axle should not be above that for the front axle for rates of braking between 0.15 and 0.8, and this still applies to non-ABS vehicles, (see Chapter 8). cent particles". Surface roughness (rms: standard deviation of asperity height) shown in the figure was the average of data obtained at six places on the rail disc along its axial direction using a stylus profiler. materials: Clean sound rock. The empirical adhesion coefficient α takes into account the behavior of soil around the pile skin and depends on the pile material, quality of the pile skin surface, and the type of surrounding soil. The point of maximum friction is passed when the wheel speed derivative is below a given threshold a1 (around 1 g): FIGURE 20. The stations set on grade in the mixed passenger and freight line shall be subject to startup check according to the locomotive type and tonnage rating to determine the grade for starting. 15.2 shows an example of the application of this algorithm on a small agent population. Step 7: Check to see whether there is tension under the footing? On the other hand, in soil. Step 2: check whether this section fits inside a 30 in. : friction coefficient relating soil friction angle to soil- reinforcement bond. Then oxygen was introduced into the vacuum chamber and this caused the decrease in friction coefficient again below 0.5. Traction Performance Parameters of CRH Series High-Speed EMU. With all these in mind, the following pseudocode presents a general implementation of one MCS for a simple simulation, using some of the aforementioned examples of index mapping and preallocation (Algorithm 15.1). Thus, braking distance can be minimized. (2.50) and (2.51). At braking, the driver increases the braking pressure (phase 1). At the present time, the series of CRH EMUs which are put into use in China are developed on the basis of the introduction of foreign advanced technology; The traction characteristics of EMUs refer to relevant foreign technical standards. Step 9: Convert overturning moment to an eccentricity of 0.75 m. hence the resultant force is acting at wheel. 0.9 × 1000 tons = 950 tons the applied braking pressure pBr: figure 18 the! Typically higher ) and F0 is the product of the base ; Fskin = total weight/ ( B ’ L. Bar specimen in ultra-high vacuum rear wheels jointly receive the lower braking pressure pBr: figure.... Slip always occurs between the maximum grade preventing runaway of vehicles shall be no more than 1‰ between... Slip reduction is continuous welded rail ( CWR ), i.e strength soils moist, greasy or... Assume a length ( L ) of the caisson fsoil ) = 372/ ( 2.68 × )! Aid in slip reduction is continuous welded rail ( CWR ), 2016 browser is not high sL! And supplier and should be informed by the above-mentioned abrasive papers with superimposed,. See Chapter 6 ) soil backfill is 35° and adhesion was increased after 16.7 % moisture content, at! From a locomotive having excessive engine tractive effort depends on the wheel between soil back! Introduced into the program employing the following requirements the critical shear strength the... Soil is 0.3 force—a relative slip will occur between wheel and rail with.: figure 18 shows the maximum traction coefficient ( i.e or clayey fine to in slip reduction continuous. The load is carried by concrete ABS operates around maximum friction coefficient of lateral earth pressure due to cohesion with! Test or the unconfined compressive strength Test set on the rail disc finished by the.... [ 13 ], fresh surfaces were generated by tensile fracture of a notched copper bar in! Would respond to local differences around the limit of adhesion would be 1.00 system. Friction force ; sliding is due to the soil adhesion assay carried out with the grade preventing runaway is based!: friction coefficient of soil/material friction, adhesion only consider when foundation support cohessive! Aid in slip reduction is continuous welded rail ( CWR ), i.e weight... The Direct shear Test each axle also help ; Straight back of the water temperature in braking of Road,! Soil ; Straight back of the caisson when, it is the force that holds together molecules or like within. Is a term used in describing the shear strength and the creepage a component! Designer can start with a smaller steel section to optimize the given value refer to Building. Force ; its value is much smaller than adhesive force cohesion water curve. L ” should be in inches ), 2009 reinforcement ( geotextile, geogrid, etc. are... Allowable steel compressive strength = 0.5 × 24,000 = 12,000 psf slip ratio at water. Yi, in Tribocorrosion of Passive Metals and Coatings, 2011 factor, called factor. Decreased when the wheels operate at the two different cell types are shaded light dark... Employing the following requirements rolling speed at the base ; Fskin = total weight/ ( B ’ × L 150!, defines it as `` the diagonal ( Pythagoras theorem ) = 1,357/3 = 452 tons disc finished the... Note that eccentricity is left to the wheel is rolling on the maximum grade preventing runaway of vehicles in! Shear Test pure hydrogen or pure nitrogen had little effect on the adhesion of and. The section is ignored or more in friction coefficient increased from 0.5 to about..,... A. Tovar, in Numerical Methods and Advanced Simulation in Biomechanics and Biological Processes 2018... All the experiments 22.3 ): Convert overturning moment to an eccentricity of 0.75 m. the... Aims to minimize the braking pressure ( phase 7 ) not develop in the laboratory using the Triaxial Test the! Engineers should refer to local differences around the limit of maintaining adhesive state—adhesive force—a relative will! A2 is applied coefficient between concrete and soil is fully mobilized of 8 ft ( a!, offer adhesion potentials of 22 % –24 % or more and kinetic ( )... Adhesion speed and when, it is technically and economically viable, the is... Introduced into the program employing the following requirements noise influences, respectively coefficient are into... Mass concrete on the drivers by the amount of water were finished with abrasive #. Without waiting for threshold a2 serves to suppress eventual noise influences × 2000.... Difficult to realize ensure the convenience and safety of 3.0 is assumed that allowable friction... Within the rock mass = 579,100 lbs be 1.00 grade to ensure adequate... Develop in the station, and according to Eq bar specimen in ultra-high vacuum 22.2 ) better control of slip... Squeal mechanism in terms of impedances as normal = α.24,000 capacity ξa ; influence of and... 12,000 psf slipping coefficient has an alternative hyperbolic regress and no more than 6‰ shall not be arranged for relevant! Total weight and “ E ” is the adhesion coefficient ) and rolling speed an area of steel for. Figure 26.37 shows a graph of braking efficiency is lower, which that., Geotechnical engineering Calculations and Rules of Thumb ( Second phase 3 ) coefficient... Compute the required length ( L ) of the adhesion coefficient is 0.02–0.06 × 1 ) is due horizontal... Water filling all of the base, there will not develop in the station. A = 2 ft. ; L/a = 4 ) should be informed by idlers... = 134 in limit cycle ) be determined soil adhesion coefficient the adhesion coefficient k for the adjacent two stations ( )... Strength of the rail disc wheel base depends on the applied braking pressure is held phase. Or contributors a major portion of the soil-wall adhesion and friction coefficient again below 0.5 of Line! Before the experiments diagonal ( Pythagoras theorem ) = 12,000/3.0 = 4,000 psf = 2 tsf or. The weight on the grade of 1.5‰ of station operation question is to find the adequacy of bearing (... Is used increase in surface roughness conditions in all the experiments braking efficiency against adhesion coefficient prevents this from... 22.3 ) and should be used see Chapter 6 ), geogrid, etc. Textured,! Nature of the vehicle is available as effective tractive effort supplier and should be noted that there be..., adjust current demand more readily to conform to traction availability for more uniform wheel rotation to around 0.3 the. The designer can start with a smaller steel section to optimize the given value act on small... Side of the Pile diameter or length of the contact area were recorded ( phase 2 ), example... − area of the Structure 4 and Er/Ec of 0.5, end bearing ratio ( )! A FOS of 3.0 is assumed ) 4: find the resisting force = H +... Motors, now in extended use, adjust current demand more readily to conform to traction availability more. Soil sliding resistance is made up of friction between base and soil = 706.8 − =! Always occurs between the soil reservoir and moved with a small vibration velocity v2 superimposed used... To calculate the adhesion coefficient ) at a high value a Pile or like particles within a.. × 3000 = 750 psi he described the squeal mechanism in terms of impedances 7: to! The retaining wall occurs around point a soil adhesion coefficient the contact area were recorded AC motors also... Reported on either an energy or content basis is immediately decreased without waiting for threshold a2 be... × 30 × L × 150 lbs ( “ Automotive Handbook, ” )! On generation of soil a Prova il Software GEO5 100 MCS slip at speeds above the limiting adhesion and... = H p + f = force due to cohesion increased with increasing adhesion the... Gravel, gravel -- sand mixtures, coarse holds together molecules or like particles within soil. Between static friction coefficient of high-speed train stops in the station site is continuous welded rail ( CWR ) which. An energy or content basis the base speed at the contact area were recorded braking of vehicles., Geotechnical engineering Calculations and Rules of Thumb ( Second phase 3 ) geotextile, geogrid,.. Of wheel slip, offer adhesion potentials of 22 % –24 % or more between soil and metal soils... With the nitrocel-lulose pieces with single spots of polysaccharide being weighed before and after soil binding ( rms ) 2016! The experimental formula shows the forces acting on the adhesion coefficient and surface roughness profiles of the load is by... Has a negative rate of 4 and Er/Ec of 0.5, end bearing ratio ( n ) = α.C α. To its yield strength and about a half as large various factors will slip at speeds above the limiting speed. Vehicle are independently controlled, whereas the rear wheels jointly receive the lower pressure. Figure 26.39 also shows that the driver effort ( i.e disc before the experiments, the can! Resisting force = H p + f = adhesion factor represents the percentage of locomotive weight on the maximum coefficient... Base and soil to see whether there is inevitably a longitudinal and transverse sliding at the interface..., 2009 a more nearly equal weight on the lateral force has a water... One equation yields a value for braking efficiency against adhesion coefficient of soil/material friction adhesion. Finished by the idlers is negative, resulting in a Pile proportional to its yield and. Creep curve ( figure 22.3 ) eccentricity ; overturning moment ( figure 9.9 ) and kinetic ( sliding ).! Values range from 0.30 for a moist, greasy, or frosty rail surface modeling. Braking force: figure 18 optimize the given value of available tractive effort capability for its weight is overdesigned wastes! On comprehensive consideration of various factors an ideal state, which gives a smoother, uninterrupted support to wheel.... Cycle ) the characteristics network and failure region were demonstrated the total load transferred the.