Rail Seat Research Articles

Numerical investigation on loading pattern of railway concrete slabs

Despite the recent surge in the construction of ballastless railway tracks, there exists a notable research gap concerning the rail seat load (RSL) associated with these track types. The RSL is the load transferred from the rail to the fastening system, the plate beneath the rail and the rail pad. The prediction of RSL in ballasted track systems is widely investigated, however, there has been a relative lack of research into the ballastless railway track systems. In this paper, a 2D finite element model (2D FEM) was adopted to evaluate the RSL concerning the effective parameters, including sleeper spacing, fastening system stiffness and the flexural modulus of the rail. The numerical model was validated through a field test performed in the study. Moreover, a mathematical expression was proposed to determine the RSL ratio for concrete slab tracks. The RSL directly correlates with the sleeper spacing and the fastening stiffness, while this relation with the flexural rigidity is inverse. Based on the results, it was found that the RSL ratio obtained from the conventional methods differed considerably from the proposed mathematical expression. More specifically, this difference was observed in almost all of the values in the sleeper spacing and flexural rigidity of rail for the Kerr model except 0.68 m and 5 MN.m2, respectively.

Improving the mechanical performance of railway concrete sleepers using recycled materials: An experimental and numerical study

This paper explores the use of three waste materials available in vast quantities, including waste tires, glass bottles and bamboo furniture, in the manufacture of railway sleepers. Mechanical properties of recycled concrete have been studied to establish an optimal mix suitable for concrete railway sleeper manufacturing. Thus, 5%, 10%, 15% and 20% recycled rubber sands (RRS) by volume of fine aggregate are used instead of 30# and 60# mesh sizes of fine aggregate. Moreover, 20%, 40%, 60%, 80% and 100% of aggregate volume are replaced by recycled glass aggregate (RGA) particles. Furthermore, different percentages of recycled bamboo fibers (RBF) have been used as 1%, 2% and 3% by volume of concrete. According to the optimal concrete mixtures of RRS, RGA and RBF, twelve concrete railway sleepers are manufactured and tested for middle and rail seat bending strengths. Results show that ref. sleeper has almost 16% and 24% lower strengths than RGA sleeper in middle and rail seat, respectively, while ref. sleeper have higher strengths by 16% and 13%, and 18% and 7% than RRS sleeper (M60-R5) and RBF sleeper (B2) in middle and rail seat, respectively. The FEM results show that the ([Formula: see text]) of the RGA sleeper is the minimum ratio by 1.11 and 1.13 for rail seat and middle of sleeper, respectively, which is the best performance. In RBF sleeper FEM model, Bamboo fiber can only bear 5% and 8% of total stress in middle and rail seat, respectively, due to low mechanical properties of fibers.

Experimental Study on Dynamic Characteristics of Damaged Post-Tensioning Concrete Sleepers Using Impact Hammer.

Concrete sleepers in operation are commonly damaged by various internal and external factors, such as poor materials, manufacturing defects, poor construction, environmental factors, and repeated loads and driving characteristics of trains; these factors affect the vibration response, mode shape, and natural frequency of damaged concrete sleepers. However, current standards in South Korea require only a subjective visual inspection of concrete sleepers to determine the damage degree and necessity of repair or replacement. In this study, an impact hammer test was performed on concrete sleepers installed on the operating lines of urban railroads to assess the field applicability of the modal test method, with the results indicating that the natural frequency due to concrete sleeper damage was lower than that of the undamaged state. Furthermore, the discrepancy between the simulated and measured natural frequencies of the undamaged concrete sleeper was approximately 1.87%, validating the numerical analysis result. The natural frequency of the damaged concrete sleepers was lower than that of the undamaged concrete sleeper, and cracks in both the concrete sleeper core and the rail seat had the lowest natural frequency among all the damage categories. Therefore, the damage degrees of concrete sleepers can be quantitatively estimated using measured natural-frequency values.

Research on inversion of wheel-rail force based on neural network framework

Wheel-rail force is a critical parameter for vehicle-track-bridge (VTB) structure system, playing a pivotal role in ensuring the safe operation of trains and service performance of track and bridge structures. This paper proposes a methodological framework for efficient and accurate prediction of wheel-rail force, that bidirectional gated recurrent unit (Bi-GRU) neural network is developed and the hyperparameters of networks are optimized through grey wolf optimization (GWO). Based on the developed VTB system model, numerical experiments are carried out to produce datasets which are verified through field test. In order to make the data more universal and comprehensive, Latin hypercube sampling (LHS) is introduced to randomize the parameters of VTB model. The datasets generated from VTB system, with rail seat force as input and wheel-rail force as output, serve as the training data for framework. Additionally, the inversion effects under various working conditions are examined and discussed. The results indicate that the model can precisely inverse continuous wheel-rail forces from the moment the wheels enter the first test rail seat until leave the last test point of rail seat. When the neural network learns from the features of at least three or more rail seats on each track slab (with intervals not exceeding 2 rail seats), it can accurately inverse the time history curve of wheel-rail forces. The framework presents a viable alternative for the wheel-rail force analysis, and promising potential for the realization of online monitoring of wheel-rail force.

Numerical investigation of prestressed concrete sleepers reinforced with high-performance macro synthetic fibres

As modern railway tracks are exposed to heavier loads and higher operational speeds, the excessive cracking and premature failure of prestressed concrete sleepers are becoming more and more critical. Towards addressing these issues, this study focuses on the numerical integration of macro synthetic (polypropylene) fibres in prestressed concrete sleepers to improve the structural behaviours (i.e. residual capacity, cracking resistance & ductility) and assess the damage evolution. Moreover, the numerical investigation performed using Abaqus attempted to validate experimental results and optimised the sleeper design by partially reducing the number of prestressing wires. The analysis reveals good agreement with the experiment at critical cross-sections (i.e. rail seat & centre) and analytically allowed a ∼ 15 % reduction in prestressing steel reinforcement for the macro synthetic fibre reinforced concrete (MSFRC) sleeper. Accordingly, the optimised MSFRC sleeper performed adequately with minimum ultimate capacity reduction that meets the permissible specifications and future demands.

Full-scale static behaviour of prestressed geopolymer concrete sleepers reinforced with steel fibres

Profusive cracking leading to the deterioration of prestressed concrete sleepers has retained the sleepers from being exploited to their full extent. In addition, excess utilization of cement in producing the same has paved the way for developing its counterpart, geopolymer concrete (GPC), involving primary industrial residues as their precursors. This study presents a comprehensive investigation into the development and performance of high-strength geopolymer concrete sleepers for railway applications. The research focuses on the complete replacement of ordinary Portland cement with Fly ash and Ground Granulated Blast Furnace Slag in the geopolymer concrete mix, for mainline prestressed railway sleepers following Indian Railway Standards (IRS). Notably, the study includes experimental validations of long steel fibers as secondary reinforcement to the primary prestressing strands, aiming to enhance the ductility of the member. Experimental validations were performed on full-scale (1:1) sleeper members under static loading conditions. The main aim of this article was to assess the load carrying capacity at cracking and ultimate limits, rail seat bending moment, ductility indices, failure mechanism, electrical impedance, bond strength, and the eco-efficiency for the proposed prestressed geopolymer concrete sleeper members (with and without steel fibres) with reference to the conventional prestressed cement concrete sleepers. The considered GPC mix was found to achieve higher load and moment carrying capacity by about 8.3% and 8.54% respectively compared to the conventional concrete mix. The addition of steel fibres in the GPC increased the load and moment capacity of sleepers by 23% and 24.21% respectively. Additionally, the steel fibre reinforced GPC showed improved displacement ductility demand over the plain geopolymer concrete averaging 25%, 28.5%, and 3% corresponding to ultimate, failure, and residual ductility index respectively. Though inclusion of steel fibers improves the performance of sleepers in terms of load and ductility, they were found incompatible with regard to the electrical impedance property when used in conjunction with the pre-stressing strands.

Investigation of Load Environment and Bending Load Capacities of Aged Prestressed Concrete Sleepers

In this study, field measurements of the bending moments of prestressed concrete (PC) sleepers installed on commercial lines were obtained, and numerical analyses to identify the effects of different parameters on their bending moments were conducted. The bending load capacities of aged PC sleepers collected from commercial lines via bending tests were also determined. According to the field measurement results of the wheel loads and bending moments of the PC sleepers, the measured values were smaller than the design values. In addition, neither the wheel load nor the bending moment depended on train speed. The numerical analysis results indicate that the positive bending moment at the rail seat section is unlikely to exceed the design decompression moment (DDM). However, the negative bending moment at the center section may exceed the DDM if center support is provided with a reduced spring constant under the rail (the “hanging” rail seat section). In addition, the bending moment increased with the rail surface roughness, so the rail should be kept smooth. Moreover, the results of the JIS E 1201 bending tests on the aged PC sleepers showed that the crack generation load and ultimate load decreased gradually with increases in age and passing tonnage. However, all samples satisfied the JIS standard values. Furthermore, the bending moments generated in the PC sleepers during train passage were considerably smaller than the crack generation load and ultimate load during the bending test. Thus, Japanese PC sleepers aged more than 50 years currently satisfy the standard flexural fracture values specified by the JIS, and safety is not immediately compromised.

Analysis of cracking evolution mode of the monobloc sleeper

PurposeMonobloc sleepers have several problems related to bending cracking, especially longitudinal cracking and cracking at rail seat under preload release. Therefore, the purpose of this study is to describe the behavior and cracking mode of prestressed concrete railroad sleepers under static loads using the positive test. Experimental tests followed by 3-D numerical models were performed of the same test.Design/methodology/approachTwo steel supports were placed on the rail seat. During a progressive loading, the initiated cracks had approximately the same amplitude as those obtained from the numerical model. The type of cracking depends on the intensity of the applied static load and the loading rate. A validated three-dimensional digital model was established. The obtained results showed a perfect resemblance to the experimental tests. The final design was optimized and verified using a validated numerical simulation.FindingsAt low static loading levels, the first flexural shear cracks appeared at a vertical position located between the two steel supports. At higher static loading levels, bending shear cracks have occurred. The latter are inclined at the steel supports. It was proven that for higher loading levels, shear cracks were the primary mode of failure.Research limitations/implicationsOwing to the sensitivity of monobloc sleepers to technology production, the results are limited by the maximal loading and press used.Practical implicationsNumerical modeling greatly reduces uncertainties in laboratory testing and is an important tool for visualizing and quantifying rail seat cracks to understand behavior and predict collapse.Social implicationsEnsuring human life during rail operations is one of our the long-term priorities. This cannot be done unless the authors manage to master the manufacturing tool for sleepers while controlling the limitation of crack propagation.Originality/valueThe three-dimensional numerical established model has been checked and validated against the experimental results using the positive test to understand the behavior and the cracking mode of prestressed concrete railroad sleepers under static loads. The proposed numerical model has been more refined for a later more complex application by reducing the computation time.

Development and performance evaluation of self-healing concrete railway sleepers using different size PU tubes

The rail seats and middle are the main critical zones in railway concrete sleepers wherein the damage normally occurs due to high positive and negative bending moments, respectively. To address this issue, self-healing concrete railway sleepers (SHCRS) were developed by reinforcing the sleepers with polyurethane (PU) filled glass tubes, and their bending performance was subsequently investigated. A total of sixteen full-scale reinforced concrete railway sleepers with different diameters of glass tubes (4 mm and 9 mm) and lengths (50 mm and 200 mm) were manufactured and tested under three-point bending at the rail seat up to 440 kN for intact and 220 kN for damaged sleepers, as well as in the middle of the sleepers at 160 kN for intact and 70 kN for damaged sleepers. The digital image correlation (DIC) method was used to study the fracture behavior of SHCRSs, evaluating the crack strains and crack width openings, and their behavior was compared with conventional reinforced concrete sleepers. Short tube sleepers perform better in the rail seat where they have a further distance to the maximum flexural zone than the middle does, almost 60 mm. Meanwhile, long tube sleepers have a better performance in the middle of the sleeper, with a distance of 40 mm from the maximum flexural zone due to the greater slenderness of long tubes as opposed to short tubes. A FE model was developed to measure different slenderness ratios for long and short tube sleepers. The results show that the slenderness ratio and surface area to volume ratios (sa/vol) of the PU tubes have a significant effect on the healing of damaged sleepers. Decreasing the slenderness ratio from 250 to 200 on the short tubes increases the applied stress by 11 % in the rail seat and 450 % in the middle of the sleeper.

Performance studies on two types of prestressed concrete railway sleepers using finite element model

Prestressed concrete sleepers [PCS] are widely used in ballasted railway tracks across the world. Sleepers distribute the load coming from the rails to the ballast. PCS have advantages like high durability, stability, and strength compared to other types of sleepers. Concrete sleepers in their life span may undergo utmost loading conditions due to high-speed rails, high-magnitude wheel loads, and rail irregularities. Cracks in sleepers may occur at the rail seat region and mid-span region because of the high positive bending moment and high negative bending moment, respectively. PCS may satisfy the excepted performance standards during short-term serviceability, but long-term durability and premature failures are still an issue. Hence, selecting a suitable sleeper that performs better during harsh loading conditions becomes crucial. In the present study, two kinds of railway sleepers, namely, Indian sleeper (RT2496/60 kg) and Chinese type III prestressed concrete sleeper [CT III PCS], are considered to assess the performance under harsh loading conditions which arise due to modern high-speed or semi-high-speed rails on ballasted tracks. The finite element models of two kinds of sleepers were done using ANSYS, and the performance of the sleepers was assessed. The numerical results show that the CT III PCS performed slightly better than the Indian sleeper that has been studied in the present investigation.

Prediction of long-term differential track settlement in a transition zone using an iterative approach

A methodology for the simulation of long-term differential track settlement, the development of voided sleepers leading to a redistribution of rail seat loads, and the evolving irregularity in vertical track geometry at a transition between two track forms, is presented. For a prescribed traffic load, the accumulated settlement is predicted using an iterative approach. It is based on a time-domain model of vertical dynamic vehicle–track interaction to calculate the contact forces between sleepers and ballast in the short-term. These are used in an empirical model to determine the long-term settlement of the ballast/subgrade below each sleeper. Gravity loads and state-dependent track conditions are accounted for, including a prescribed variation of non-linear stiffness of the supporting foundation along the track model. In parallel, a two-dimensional (2D) non-linear finite element model of layered soil is verified versus field measurements and used to determine the support stiffness of each sleeper in the track model. The methodology is applied to a transition zone between a ballasted track and a slab track that is subjected to heavy haul traffic. Analyses of the influence of higher axle loads and the implementation of under sleeper pads on sleeper settlement are demonstrated.

Relationship between track geometry defect occurrence and substructure condition: A case study on one passenger railroad in the United States

Analyzing the relationship between track geometry defect occurrence and substructure condition can provide assistance for track inspection and spot maintenance, which contributes to better train operation quality. This paper develops a data-driven approach to estimate the occurrence of track geometry defects on concrete-tie tracks on one passenger railroad in the United States, using substructure data, rail seat abrasion data, infrastructure data, traffic data, track class information, and maintenance data. Feature extraction was implemented to generate input variables for the machine learning models. Recursive feature elimination (RFE) was applied to reduce data dimensionality by recursively considering smaller sets of features. Three data treatment methods, including no resampling, undersampling, and oversampling, were incorporated to address imbalanced data issues. The developed models included logistic regression, artificial neural network, and gradient boosting. The hyperparameters of the proposed models were optimized using Bayesian optimization. The performance of the proposed methods was finally evaluated based on the test dataset generated using random data partitioning. Based on data collected from one passenger railroad, the gradient boosting method with data oversampling shows the highest performance in estimating the occurrence of geometry defects. The F1-score of the model is 0.662, with G-Mean of 0.738. Feature importance identifies that surfacing, traffic, curvature, switch, and rail replacement are the top five factors influencing the predicted probability of track geometry defect occurrence. The proposed model can be used to prioritize maintenance activities on locations prone to track geometry defects and thus further improve infrastructure safety given budgetary constraints.

Sitting comfort analysis and prediction for high-speed rail passengers based on statistical analysis and machine learning

Various comfort evaluation models have been extensively studied for improving driver seat and office seat designs for the purpose of improving seat comfort. High-speed rail (HSR) seat comfort is influenced by specific environments, activities, and postures, and targeted in-depth research on this topic is lacking. Existing evaluation cannot ensure the validity of data at the early stages of model training because of their direct reliance on subjective evaluation data, thereby limiting the improvement in the accuracy of prediction. In this study, we designed a sitting observation experiment and static sitting comfort experiment for the typical activities of HSR passengers. The sitting posture of HSR passengers under typical activities was classified for different comfort levels based on the factors influencing the sitting posture in terms of bone and muscle biomechanics. The correlations between the subjective discomfort in different sitting positions, objective change patterns, and body pressure distribution parameters were statistically analysed. The possibility of using sitting duration and sitting frequency as objective behavioural indicators of discomfort evaluation was indicated. Based on the verification of the reliability of the evaluation data, the classification performance of various machine learning algorithms was compared and analysed, and a sitting comfort prediction model was established based on the gradient boosting machine algorithm, with an accuracy of 89.5%. This study serves as an effective reference for improvement strategies for HSR passenger comfort and will inspire new ideas for exploring objective indicators for sitting comfort evaluation.

Synthesis of novel Si–P–N complex coating for the fabrication of flame-retardant and hydrophobic cotton textile potentially suitable for rail seat cover

In this study, we fabricated a fancy cotton textile with sustained flame retardancy and hydrophobicity by dip coating the fabric with two complex solutions (CS). Solutions A and B consisted of chitosan, urea, phytic acid, tetraethyl orthosilicate, and hexamethyldisiloxane, which were rich in silica (Si), phosphate (P), and amide (N). The chemical interaction and surface morphology of the CS coated on the textile were verified by Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray (SEM-EDX) spectrometry. Thermogravimetric analysis, differential scanning calorimetry, an ASTM D6413 vertical flame test, and cone-calorimeter test were conducted to study the thermal and flame-retardant properties. The IR spectral peaks at 730, 820, and 1540 cm−1 are the main evidence for chemical interaction, and a uniform distribution can be seen in the SEM-EDX analysis. The thermal stability was significantly enhanced by producing char from 6.7 to 33.5 % at 700 °C. Surprisingly, the cotton textile exhibited self-extinguishing behavior. This was evidenced by the shortened burning length from 300 to 84 mm during 12 s of flame exposure in the VF test, as well as reductions in the peak heat-release rate and total heat release rate from 203 to 21 kW/m2 and from 20.1 to 2.8 MJ/m2, respectively. The hydrophobicity of the textile increased upon application of the CS coating, with a contact angle (CA) of 127°. Practical examination confirmed that the treated fabric was well suited for seat upholstery.

Structural behaviour of prestressed concrete sleepers reinforced with high-performance macro synthetic fibres

The application of macro synthetic fibre reinforced concrete (MSFRC) innovatively addresses the current cracking and corrosion issues associated with the prestressed concrete railway sleeper. In this paper, a structural assessment of traditional concrete sleepers reinforced with high-strength, prestressed steel and macro synthetic fibres is provided. Detailed review on the rail seat and centre sections of the railway sleeper is presented to critically evaluate the mechanical benefits and feasibility of a complete replacement of prestressed steel with macro synthetic (polypropylene) fibres. Three types of sleeper were individually subjected to both positive and negative moments at these critical sleeper sections for their performances to be compared at cracking, ultimate capacity and failure. Accordingly, the potential implementation of MSFRC in sleepers has been proposed to cost-efficiently improve the current design for the railway industry.

Progressive failure analysis of partially pre-stressed concrete railway sleepers

Billions of sleepers are used on railways around the world today. As the importance of railways in the transportation sector is increasing, the demand for sleepers is also increasing. Although wooden and steel sleepers were used in rail systems in the past, today the most widely used sleeper type in the world is reinforced concrete sleepers. Among these reinforced concrete sleepers, pre-stressed sleepers are the most widely used, popular type of sleeper that can be produced in many countries. The two main production methods of pre-stressed sleepers are the ribbed reinforced system and the non-ribbed reinforced anchor plated system. In this study, B70 type pre-stressed concrete sleepers, have been investigated with the positive moment determination tests at the rail seat with progressive failure observations according to EN 13230-2:2016 standard. After tests, detailed cracking, failure, and fatigue analyzes under increasing test loads were performed with ANSYS® finite element analysis results for both types of pre-stressed sleepers. According to results, A-type sleepers have 50% more compression stress at the first crack formation load (Frr) than N-type sleepers and According to the first 0.05 mm permanent crack formation load (Fr0.05), it is seen that 25% higher stresses occur in A-type design than N-type design under Fr0.05 load. The results obtained through the analysis have been compared with the actual field measurement results, which have become more and more popular in the world in recent years. In this direction, various suggestions have been made for the development of concrete railway sleeper models.

Investigation on Prestressed Concrete Sleeper (PCS) Subjected to Dynamic Loading on Site and Experimental Works.

The purpose of the research was to study the condition of prestressed monoblock concrete sleeper (PMCS) under dynamic loading experimentally and through site investigation. From this research, the value of deflection base on acceleration of concrete sleepers have been obtained. This study showed the possible correlation and relation of the PCS deflection located under a railway track. This research includes experimentation process which includes experimental investigations for dynamic loading of prestressed concrete sleepers (PCS) were examined in terms of its capability to accommodate their own design capacity and the relationships between load and displacement happened within the concrete sleeper. This study will help the railway authorities to understand and take any maintenance action to their rail infrastructure. From experimental test, the highest deflection on KTMB and EPMI rail seat section is 1.35 mm and 1.04 mm respectively. From site investigation at KM20.75, the highest deflection occured is 5.993 mm which is lower compared to the highest deflection at KM26.25 with the value of 7.06 mm.

Improvement of mechanical properties of railway track concrete sleepers using ultra high performance concrete (UHPC)

In recent times, the shape of the beams evolved from wooden sleepers and then to steel sleepers until they reached concrete sleepers. These sleepers play a very important role in transferring the loads from the train wheels to the subgrade layers fixed by the railway. This development took place in concrete sleepers until we reached mono-block concrete sleepers. This paper discusses, through laboratory experiments, the effect of ultra-high performance concrete mixtures on the behavior of mono-block concrete sleeper B70. The ability of these new sleepers to resist train loads was also studied, compared to its conventional concrete sleepers. This research aimed to determine through experiment if these sleepers' behavior fulfilled the European requirements standers for prestressed concrete sleepers, and make comparisons between the UHPC sleepers and conventional concrete sleepers. All these sleepers were tested under static load tests at the rail seat and center section and pull-out tests for cast-in fastening components. These initial results suggest that a new generation of Ultra-high performance concrete sleepers can be created; the long-term efficiency of this category of sleeper will need to be confirmed by dynamic and fatigue tests and practical use.

A bi-block sleeper dynamic strain monitoring method based on embedded FRP-OF sensor

The traditional surface contact monitoring, in which sensors and wires are exposed outside, has a great risk on long-term monitoring at high-speed railway (HSR). This paper proposed a method that embedding the Fiber Reinforced Polymer-Optical Fiber (FRP-OF) sensor into the bi-block sleeper, which was designed for long-term monitoring of sleeper dynamic strain at high-speed railway. Sleeper is the key component of bi-block ballastless track that bears and transmits the load from wheel. Its internal dynamic strain somehow reflects the wheel/rail force under the high-speed train load. Considering the symmetry of bi-block sleeper, a single block of sleeper was selected for this research. To validate the feasibility of monitoring sleeper strain by embedding FRP-OF sensor in sleeper, both laboratory static test and field dynamic test have been conducted. The results showed that there was a linear relationship between the sensor response and the applied load in the laboratory static test. The wheel load ratio assigned to each sleeper and the mechanical behavior is verified theoretically and experimentally. The single wheel load is mainly borne by five sleepers below the rail, which bearing 8%, 22%, 32%, 22%, 8%. Then, the load of different train can be sensed by the sensors in the field dynamic test, which clearly identified the process of wheel action and showed good repeatability. The dynamic strain in sleeper was about 3-7με with 150kN axle load at 350 km/h, which was converted to rail seat force of 33-35kN, and 7-18με with 230kN axle load at 160 km/h which was converted to rail seat force of 89-96kN. The impact factors on the track are different since the difference of the vechicles load. In general, the vertical transient strain level of sleeper is low, but the trend of strain variation is obvious and accords with the characteristics of wheel load distribution ratio. It can be seen that the sensors had good performance on dynamic strain monitoring of bi-block sleeper, which will be used as the important supplementary means of the future wheel/rail force monitoring.

Discrete element method analysis of lateral resistance of different sleepers under different support conditions

With the increasing speed of trains and the axle load of railways, the need to provide lateral stability of railways becomes more important. Small-radius curves on conventional tracks and temperature fluctuations pose a significant threat to the lateral stability of railway tracks as they increase lateral and longitudinal forces, leading to track buckling. Therefore, the lateral resistance of ballasted railway tracks must be improved in every way possible. To this aim, many approaches have been proposed, including modifying ballast and sleeper materials, changing the ballast layer geometry, and replacing conventional sleepers with specialized ones. Compared to conventional B70 sleepers, applying HA110, winged and middle-winged sleepers improved the lateral resistance by 31%, 50% and 17%, respectively, according to the findings of a Single Tie Push Test (STPT). Ballast supports often fail to ideally cover the sleeper bed. Thus, the lateral resistance of four different types of sleepers (i.e., HA110, winged, middle-winged, and B70) under four different support conditions (i.e., lack of rail seat support, full support, lack of center support, high center binding) with/without shoulder and crib ballasts was investigated by discrete element method (DEM). The results revealed that winged and HA110 sleepers showed similar behavior in providing the lateral track resistance without considering crib and shoulder ballasts in the absence of center and high center binding support conditions, while winged sleepers exhibited the highest lateral resistance in the presence of crib and shoulder ballasts in full support, lack of rail seat support, and lack of center support.