Wooden Sleepers Research Articles

Analysis of the labor consumption and duration of the assembly processes of structural coating plates blocks using the crane method

The labor intensity of the construction process is determined by the methods of technical standardization of processes by the methods of time tracking. On the basis of these observations, regulations are developed in the form of GN or other collections of norms of labor costs. Labor intensity is measured in person–hours, and the rate of labor costs is derived from the rate of time, taking into account the number of performers. Variants of consolidation and installation of structural plates of the covering are not typical. The main processes necessary for the duration and labor–intensiveness of the structural slabs of the coating by the free method have been analyzed. A potential development has been identified that will ensure a reduction in the labor–intensiveness of the assembly process and provide cyclical assembly work. The consolidation process is optionally performed on the assembly stand, which belongs to the assembly equipment equipment. To install the stand, a site is specially prepared in the form of a horizontally planned surface of the earth with a layer of compacted crushed stone. Cells made of wooden sleepers are placed on the crushed stone, which are set according to vertical planning marks with the help of geodetic devices. Then a collection stand is installed on the sleeping cells. Structurally, the stand consists of several parts. That is why the manufacturability of the installation of the structural plates of the covering was improved by means of constructive and technological solutions. First, the columns are mounted (columns with a height of 12 m were used for the analysis), so it is not possible to carry out consolidation in the area of the columns. The stands are placed next to each other in the working area of the crane. All calculations were performed in tabular form according to the formula. The installation process of 12 m high columns includes the sub–processes of unloading and disassembly, installation and fastening. The components of these processes are actions (operations). According to the methodology, a schedule of the processes of consolidation and installation of blocks of structural slabs with preliminary installation of columns according to the corresponding calculations was built.

Performance Evaluation of Carrying Capacity of Prestressed Bearers for Railway Turnouts Using Laboratory Experiments in Vietnam

Previous studies have addressed railway turnouts (switches and crossings), but research on the performance of 1000 mm gauge turnouts is limited. At present, wooden sleeper structures are used at turnouts in Vietnam. However, these structures have many disadvantages in the operation process. This paper evaluates the performance of new prestressed bearer (PSB) for turnouts, designed for the 1000 mm gauge, to overcome the disadvantages of a wooden sleeper. Test samples of PSB were manufactured in the factory, and experiments were conducted in the laboratory according to European Standards to evaluate the PSB carrying capacity. The test results show that the proposed structure meets the carrying capacity under the standard test loads. In addition, the results of the static and fatigue tests of the bearers show a considerable reserve in the cross-section capacity. This means that the existing reserve can be used with a larger locomotive axle, and the bearer design can be optimized by arranging the prestressed strands and changing the bearer cross-section’s geometric dimensions. It is hoped that the proposed bearer design will be a viable alternative for designing railway turnouts.

Potential of frost damage of off-ground foundation stones in Norwegian Stave Churches since 1950 using land surface temperature

The Stave Churches (SCs) are one of the most iconic heritages in Norway, and only 28 medieval SCs have survived till our age in this country. They are built on wood with staves and wooden sleepers standing off the ground on foundation stones which have the primary purpose of guaranteeing structural support, ensuring integrity of the leveled foundation, and avoid ground water or rainwater penetration up to the valuable wooden structures. This paper aims to analyze the risk of Freeze-Thaw (F-T) decay on the foundation stones of the 28 SCs using an algorithm with a single climate input parameter i.e., the land surface temperature, extracted from the Global Land Data Assimilation System GLDAS which integrates satellite- and ground-based observational data products. The novel proposed algorithm estimates a climate-based index of F-T risk on foundation stones starting from the analysis of the variability of a 70-year (i.e., 1950 to 2020) land surface temperature datasets at these 28 locations. The outcome is further used to evaluate the average lifetime (half-life time) of foundation stones as well as the number of interventions necessary to guarantee their structural soundness thus providing a quantitative, predictive, and timely effective information to SC churches managers, and conservators on the climate change effect on foundation stones degradation at support of prioritization of maintenance interventions.

Numerical and experimental investigation into longitudinal resistance of ballasted railway track with wooden sleepers

• Test series were done on different lengths of test panels to understand the track longitudinal behavior along the rail axle. • The 3D finite element model was verified according to the test results. • The sensitivity analysis was done to find the most influential factors in longitudinal resistance and stiffness. • Increasing cohesion from 500 Pa to 2000 Pa increased the TLRF and TLS by 63 %. • This value for the increasing friction angle from 25° to 45° was obtained as 56.5% for TLS and 66.9 for TLRF. A ballasted railway track's longitudinal stiffness and resistance with wooden sleepers were experimentally and numerically investigated. The longitudinal resistance was measured by measuring the force and displacement in the rail's axial direction by increasing the number of sleepers from one to five. The track longitudinal stiffness (TLS) and resistance force (TLRF) of the five-sleeper panel in the experiments were obtained as 15.3 kN/mm and 37.2 kN, respectively. The increased ratio of longitudinal resistance force per sleeper with increasing sleepers' numbers was measured constant. Next, a 3D numerical model was built based on the finite element method, it was verified with test results. TLS and TLRF were reported as 36.75 kN and 15.42 kN/mm in the numerical model. TLS and TLS sensitivity analyses were executed with influential parameters such as ballast property and ballast geometry. The models revealed that vertical load (140 kN) had maximum impact on TLRF with the increasing percentage of 190 %. Finally, two equations were proposed to estimate the variation of TLS/sleeper and TLRF/sleeper with R 2 = 0.95 ∼ 0.97.

Myths and Realities of the Salt Lake Temple Foundation

Myths and Realities of the Salt Lake Temple Foundation

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.

Incising and Double Impregnation of Beech Sleepers—Investigation of an Alternative Preservation System for Wooden Railway Sleepers

For nearly 200 years wooden railway sleepers are impregnated with creosote. After initially using vacuum pressure processes for impregnation, empty-cell processes have been developed quickly and are used until today. Because of political developments and its alarming properties against human health and environment the use of creosote is already restricted to certain industrial and commercially used products and will probably be banned on the European market and elsewhere in the near future. Today, most of the sleepers in track are concrete sleepers, but wooden sleepers are still essential for particular applications such as tracks with narrow curve radii, mountain tracks with uneven underground conditions and low ballast bed thicknesses, for switches, for railway bridges and for shunting stations. Without a successor product, wooden sleepers have to be installed either again without adequate protection against wood destroying organisms or will possibly be replaced by sleepers made from alternative materials like concrete, steel or polymers. The Fürstenberg-System-Sleeper, which combines a mechanical pre-treatment (incising), a double impregnation of sleepers including an alternative oily wood preservative and a water-borne copper salt as well as a modernized quality control shall on the one hand serve as an alternative to creosoted sleepers and on the other hand ensure future use of wooden sleepers in track superstructure. Incising reduced the formation of checks regarding their length, width, and depth in sleepers made from European beech (Fagus sylvatica L.) until they are sufficiently seasoned for impregnation. A decrease of the seasoning speed was not observed. During seasoning, the average global moisture content (MC) as well as the local MC showed hardly any differences between incised and not incised sleepers. Additionally, incising showed no influence on the dimensional stability, which would have reduced the number of sleepers being culled based on excessive deformation. Furthermore, positive effects on preservative retention and penetration were observed, where incising doubled the penetration depth up to over 30 mm and increased the mean retention from 46.5 to 72.0 kg/m3. During double impregnation with the water-borne preservative first and the oily preservative afterward, it became evident, that a gross weight of at least 950 kg/m3 was needed for penetrating the peripheral area of the sleepers to achieve an additional homogenous envelope treatment during the second impregnation with an average retention of approximately 30 kg/m3.

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.

The current state of the circular economy in the Russian Federation: problems of utilization of waste wooden sleepers

The current state of the circular economy in the Russian Federation: problems of utilization of waste wooden sleepers

Testing of Railway Prestressed Concrete Sleepers Using Acoustic Emission

The article describes the tests of prestressed concrete sleepers made according to the method specified in the requirements of the European standards (EN 13230-2:2009 Railway applications – Track – Concrete sleepers and bearers – Part 2: Prestressed monoblock sleepers) and WTWiO regulations, and an additional measurement method was used – acoustic emission (AE). The purpose of the tests using the acoustic emission method was to verify the results obtained using other test methods de-scribed in the European standard. The use of this method in sleeper tests enables obtaining precise data from the sleeper load test and determination of the characteristic parameters based on the recorded AE signals. Due to the variety of existing sleepers and the development of products in this area: wooden sleepers, composite sleepers, steel sleepers (type Y), the use of the acoustic emission method in research will be a good support and will enable proper assessment of these elements of the railway road.

Numerical studies to evaluate crack propagation behaviour of prestressed concrete railway sleepers

The prestressed concrete sleeper is a primary type of sleeper for railway systems around the world. Compared with wooden and composite sleepers, concrete sleepers are of good elasticity and sufficient longitudinal and lateral resistance to ensure the stability of the track. As the railway system is developing to a heavier load and higher speed system, the cracking of concrete sleepers under dynamic load and long-term service is becoming more and more critical. It is essential to evaluate the crack behaviour of prestressed concrete sleepers. In this paper, three-dimensional FEM models have been established using Abaqus based on the brittle cracking model. After the validation by experimental results, the numerical research is performed to evaluate the crack propagation behaviours of prestressed concrete sleepers with different concrete compressive strength, different prestressing force magnitudes, and different loading rates. The results reveal that the cracking resistance of a concrete sleeper turns enhanced by improving the compressive strength of concrete and the initial prestressing force of tendons. It is also observed that the cracking becomes more progressive as the loading rate increases.

A new approach for evaluating lateral resistance of railway ballast associated with extended sleeper spacing

Recently, attempts have been made to replace wooden sleepers with concrete sleepers with expanded sleeper spacing, especially on conventional railway lines. By extending sleeper spacing in the replacement process, the number of sleepers required is lower. A reduction in the number of sleepers can reduce replacement costs. Behind this attempt to change materials and spacing is the generally held notion the lateral resistance of a ballast is unchanged after the change in the sleeper spacing, whether it is a wooden or a concrete sleeper. However, the changes in the interference degrees of adjacent sleepers and in the rail weight supported by each sleeper are expected to affect the lateral resistance of the ballast. They can change the lateral stability of ballasted tracks in a more complicated fashion than the simple effect of a reduced number of sleepers. However, the current standard design does not consider the combined effects of these changes on the lateral resistance of a ballast. Accordingly, the design of ballasted tracks with extended sleeper spacing cannot be optimized.Therefore, the aim of this study was to investigate the lateral resistance characteristics of a ballast as associated with changes in the sleeper spacing of conventional railway lines. First, single-sleeper pullout tests were conducted on models based on various sleeper spacing conditions to evaluate the lateral resistance of the ballast. The effect of the rail weight on the lateral resistance of the ballast was determined from the test results. An increased frictional resistance at the sleeper bottom was considered to contribute to an increase in the lateral resistance; thus, the friction angle between the ballast and sleeper bottom was used to evaluate the degree of increase. Subsequently, track panel pullout tests were conducted by simulating an expansion of the sleeper spacing. Based on the test results, the effect of the interference between adjacent sleepers on the lateral resistance per sleeper was investigated. The obtained results were quantitatively modeled as a function by using the sleeper width as a parameter (as normalized by the sleeper spacing). Finally, a new approach was proposed for estimating the lateral resistance of a ballast which considered the change in the sleeper spacing for conventional railway lines. The method considered the combined effects of change in the interference of adjacent sleepers and in the rail weight supported by each sleeper on the lateral resistance. Based on the results calculated by the proposed method, practical applications were examined by determining the extent to which the sleeper spacing could be increased without reducing the lateral resistance of the ballast when replacing wooden sleepers with concrete sleepers. It was demonstrated that the proposed method could improve the estimation accuracy of the lateral resistance of a ballast track with extended sleeper spacing.

INVESTIGATION OF THE MANIFESTATIONS OF ROCK PRESSURE IN A DEEP MINE WITH A STEEP OCCURRENCE OF COAL SEAMS

The purpose of the work. Investigation of the manifestations of rock pressure in the retractable road of a steep coal seam to ensure the operational state of production and increase the safety of work at the excavation site of a deep coal mine. The research used a comprehensive approach, including analysis and generalization of theoretical and experimental research on this problem, field experiment to study the stability of retractable drifts and processing of experimental data. To assess the stability of the preparatory workings, mine studies were performed to study the manifestations of rock pressure in the retractable drift under different methods of protection, when the magnitude of the displacement of lateral rocks on the contour and change the cross-sectional area of the drift along the excavation section. As a result of the performed researches the conditions of stability of retractable drifts of steep coal seams at protection by fires from wooden sleepers and bushes from risers are substantiated. It is recorded that in the zone of influence of mining works, the fastening in the retractable road is deformed and has characteristic curves from the roof. At a distance of l > 80 m behind the clearing face, the loss of the cross-sectional area of the excavation was about 50 % with the method of protection by bushes from the risers and 30 % with the use of wooden fires. It is experimentally proved that with the method of protection of precinct preparatory workings by rigid wooden structures in the form of bushes from risers, the change of cross-sectional area of the retractable lane behind the treatment face in the area of impact of treatment works occurs linearly with increasing length of the excavation site. To ensure the stability of retractable drifts in a deep coal mine with a steep occurrence of coal seams, it is advisable to use aimless methods of protection, when to support the side rocks are used pliable structures in the form of fires made of wooden sleepers. The use of this method of protection of the preparatory workings can reduce the likelihood of landslides and increase the safety of mining operations.

THEORETICAL RESEARCH OF THE POSSIBILITY OF JOINTLESS TRACK ARRANGEMENT IN CURVED SECTIONS OF RADIUS LESS THAN 350 METERS

The traditional structure of the upper structure of the track on the main railways of Ukraine in curved sections with a radius of less than 350 m is a link structure of the track with wooden sleepers. This track design is not rational under current operating conditions. The use of a more advanced jointless track design in curves with a radius of less than 350 m is limited primarily by the condition of ensuring the transverse stability of the rail-sleeper lattice. To be able to expand the use of jointless track construction in curved sections with a radius of less than 350 m, it is necessary to know the values of the transverse forces of interaction of the structures of the upper track structure with the moving carriage. Knowing the forces of interaction, it is possible to estimate by what value the transverse stability of the rail-sleeper lattice will be provided and to make constructive decisions on its increase. The method of determination of transverse horizontal forces of interaction of track and moving carriage in curves of radius less than 350 m taking into account quasi-static compressive forces in a train is given. The reasons for these forces are related to the presence of eccentricity of the autoclutch shank in the horizontal and vertical planes. Theoretical calculations of horizontal transverse forces of interaction are carried out according to the given technique and coefficients of stability of a rail-sleeper lattice in curved sites are defined. The main conclusions concerning the possibility of operation of the jointless track structure in curved sections with a radius of 350 m and less are made.

Comparative analysis of resistance characteristics of composite sleeper and concrete sleeper in ballast bed

A composite sleeper has a similar shape, stiffness, and weight to that of an existing wood sleeper with additional benefits including excellent durability, extended design life like a prestressed concrete sleeper, environmentally friendliness, and cost effectiveness. Therefore, in some cases, composite sleepers are considered as an alternative for wooden or concrete sleepers. In this study, the longitudinal- and lateral-displacement resistance changes of the fiber reinforced foamed urethane (FFU) composite sleepers and the concrete sleepers in ballast beds were tested. The application conditions of the composite sleeper in a ballast bed were analyzed. The results show that the resistance of the composite sleeper changed more sharply, and its value was greater than that of the concrete sleeper during the initial stage of their displacements. The longitudinal and lateral resistance of the composite sleeper was lower than that of the concrete sleeper with an increase in displacement (at 2 mm, longitudinal: 41.35% of the concrete sleeper, lateral: 35.64% of the concrete sleeper). Using the discrete element method (DEM), it was found that when the composite sleeper moves, the ballast around it may ‘rebound.’ The force and its transfer of the ballast near the displacement end of the concrete sleeper was an upward arc, while that of the composite sleeper was a downward arc. The ballast on the side of the concrete sleeper moved upward (tending to be horizontal) along the lateral-displacement direction of the sleeper, while that of the composite sleeper moved downward (tending to be vertical).

Application of Deep Learning Networks to Segmentation of Surface of Railway Tracks.

The article presents a vision system for detecting elements of railway track. Four types of fasteners, wooden and concrete sleepers, rails, and turnouts can be recognized by our system. In addition, it is possible to determine the degree of sleeper ballast coverage. Our system is also able to work when the track is moderately covered by snow. We used a Fully Convolutional Neural Network with 8 times upsampling (FCN-8) to detect railway track elements. In order to speed up training and improve performance of the model, a pre-trained deep convolutional neural network developed by Oxford’s Visual Geometry Group (VGG16) was used as a framework for our system. We also verified the invariance of our system to changes in brightness. To do this, we artificially varied the brightness of images. We performed two types of tests. In the first test, we changed the brightness by a constant value for the whole analyzed image. In the second test, we changed the brightness according to a predefined distribution corresponding to Gaussian function.

Mathematical Model Coupled to Neural Networks Calculates the Extraction Recovery of Polycyclic Aromatic Hydrocarbons in Problematic Matrix.

Unknown extraction recovery from solid matrix samples leads to meaningless chemical analysis results. It cannot always be determined, and it depends on the complexity of the matrix and properties of the extracted substances. This paper combines a mathematical model with the machine learning method—neural networks that predict liquid extraction recovery from solid matrices. The prediction of the three-stage extraction recovery of polycyclic aromatic hydrocarbons from a wooden railway sleeper matrix is demonstrated. Calculation of the extraction recovery requires the extract’s volume to be measured and the polycyclic aromatic hydrocarbons’ concentration to be determined for each stage. These data are used to calculate the input values for a neural network model. Lowest mean-squared error (0.014) and smallest retraining relative standard deviation (20.7%) were achieved with the neural network setup 6:5:5:4:1 (six inputs, three hidden layers with five, five, and four neurons in a layer, and one output). To train such a neural network, it took less than 8000 steps—less than a second––using an average-performance laptop. The relative standard deviation of the extraction recovery predictions ranged between 1.13 and 5.15%. The three-stage recovery of the extracted dry sample showed 104% of three different polycyclic aromatic hydrocarbons. The extracted wet sample recovery was 71, 98, and 55% for phenanthrene, anthracene, and pyrene, respectively. This method is applicable in the environmental, food processing, pharmaceutical, biochemical, biotechnology, and space research areas where extraction should be performed autonomously without human interference.

Effective Method for Diagnosing Continuous Welded Track Condition Based on Experimental Research

The correct operation of the continuous welded track requires diagnosing its condition and preparation of track metrics requiring measurements of displacements of rail under operation. This is required as there are additional thermal stresses in the rails with values depending on the temperature changes of the rails. Therefore, the climatic conditions are important. This paper presents the original effective analytical method for diagnosing the condition of continuous welded track based on experimental research. The method allows for an appropriate repair or maintenance recommendation. In the experimental research, the authors considered track diagnostic conditions for two conditions: track under load and track without load. This paper presents empirical formulas for calculating rail temperature and longitudinal force based on ambient temperature, developed from long-term measurements. The formulas were developed for a track located on a straight section—both for a rail loaded and unloaded with a passing train under the following conditions: 60E1 rail, not on an engineering structure, conventional surface, wooden sleepers and very high train traffic load. The obtained results in the value of the correlation coefficient R2 ≥ 0.995 attest to very high accuracy of the calculations performed with the method proposed by the authors.

A New Method for Solving the Problem of Determining the Characteristics of Spatial Stiffness and Elasticity of the Rail Threads and Stresses and Strains in Rails

The reference data given in technical literature on the characteristics of spatial stiffness and elasticity of rail threads in the conditions of joint action on the rails of vertical and horizontal lateral forces and torsion are very different and in some cases contradictory. This situation is due to the lack of an accurate analytical solution to this problem and the provision for reference materials only experimental research data, which are clearly different, not only for different railway structures, but also significantly differ in different conditions of acting external forces (P, H, Mtor). The purpose of this article is to present a new method of analytical solution of the problem of determining the spatial characteristics of stiffness and elasticity of rail threads and also computation the stresses and strains that occur in them, under conditions of complex joint action on rail threads of vertical and horizontal dynamic forces (Pdyn, Hdyn) simultaneously with the external torque moment Mtor arising from off-center forces applied to the rails from wheel loads. The complex method of solving the problem was used in the paper. It includes the theoretical part and the results of the experiment. Using the experimental researches characteristics of horizontal lateral stiffness of the rail threads of the head and sole at different constructions of the modern rail fastenings was measured. The second task of determination of the real values of the characteristics of spatial elasticity and stiffness modulus of the rail thread under joint vertical and lateral horizontal bends of the rail in conjunction with its simultaneous torsion was solved by the theoretical methods. As the results of author’s researches were obtained new values of the characteristics of spatial stiffness and elasticity modulus of rail threads under joint vertical and lateral horizontal bends of the rail in conjunction with its simultaneous torsion. These characteristics were obtained for the modern railway track constrictions with rails (R65, R50, UIC60) on concrete and wooden sleepers and with rail fastenings unlined or lined types (KB, KPP-5, KPP-1, D0). And also these characteristics were obtained in the functional dependence on the ratio of vertical and horizontal lateral forces P/H.

Commissioning of the freight wagons with increased axle loads is a guarantee of the further development of railways of the Republic of Uzbekistan

The aim of the study is to select rational axle loads of the rolling stock and establish the conditions for their circulation on the railways of the Republic of Uzbekistan. In this work, research has been carried out to assess the indicators of the stress-strain state of rail track elements from the action of the rolling stock with various axial loads. The dynamic loads from the rolling stock wheel on the rail, tensile stresses at the edges of the rail foot, in wooden sleepers (rubber under-rail pads on reinforced concrete) under the linings, in the ballast under the sleeper, as well as stresses at the main area of the roadbed, were determined. The obtained results of studies on the determination and assessment of the loading of the elements of the permanent way and sub-grade bed under the condition of not exceeding their standard values made it possible to establish the permissible speeds of movement of freight wagons with increased axle loads of 25 and 27 tf on the railways of the Republic of Uzbekistan, depending on the design of the track and the thickness of the ballast layer, which will increase the running and carrying capacity of the most loaded sections of the railway network, reduce operating costs, increase the volume of freight traffic by rail, which will create conditions for the further development of national rail transport in the implementation of export and transit potential.