Traction Unit Research Articles

Lumbar mechanical traction: a biomechanical assessment of change at the lumbar spine

BackgroundLumbar traction is a traditional treatment modality for chronic low back pain (CLBP) in many countries. However, its effectiveness has not been demonstrated in clinical practice because of the following: (1) the lack of in vivo biomechanical confirmation of the mechanism of lumbar traction that occurs at the lumbar spine; (2) the lack of a precise delivery system for traction force and, subsequently, the lack of reproducibility; and (3) few randomized controlled trials proving its effectiveness and utility.MethodsThis study was planned as a preparatory experiment for a randomized clinical trial, and it aimed (1) to examine the biomechanical change at the lumbar area under lumbar traction and confirm its reproducibility and accuracy as a mechanical intervention, and (2) to reconfirm our clinical impression of the immediate effect of lumbar traction. One hundred thirty-three patients with non-specific CLBP were recruited from 28 orthopaedic clinics to undergo a biomechanical experiment and to assess and determine traction conditions for the next clinical trial. We used two types of traction devices, which are commercially available, and incorporated other measuring tools, such as an infrared range-finder and large extension strain gauge. The finite element method was used to analyze the real data of pelvic girdle movement at the lumbar spine level. Self-report assessments with representative two conditions were analyzed according to the qualitative coding method.ResultsThirty-eight participants provided available biomechanical data. We could not measure directly what happened in the body, but we confirmed that the distraction force lineally correlated with the movement of traction unit at the pelvic girdle. After applying vibration force to preloading, the strain gauge showed proportional vibration of the shifting distance without a phase lag qualitatively. FEM simulation provided at least 3.0-mm shifting distance at the lumbar spine under 100 mm of body traction. Ninety-five participants provided a treatment diary and were classified as no pain, improved, unchanged, and worsened. Approximately 83.2% of participants reported a positive response.ConclusionLumbar traction can provide a distractive force at the lumbar spine, and patients who experience the application of such force show an immediate response after traction.Trial registrationUniversity Hospital Medical Information Network - Clinical Trial Registration: UMIN-CTR000024329 (October 13, 2016).

A COMBINATION OF DISCRETE EVENT SIMULATION AND MULTI-CRITERIA ANALYSIS TO CONFIGURE SUGARCANE DROP AND HOOK DELIVERY SYSTEMS

This article explores the decision analysis regarding Drop and Hook (D&H) transportation operation within sugarcane mills. By means of a case study, a combination of a discrete event simulation model and multi-attribute utility theory was used to evaluate different alternatives of sugarcane delivery systems using internal, external or even not using D&H. D&H strategy maximizes the use of trucks, since semi-trailers can be handled independent of the traction unit of the trucks, which makes the transport system more agile. Internal D&H considers the semi-trailer detaching/attaching point positioned inside the mill site while External D&H is located outside it, before trucks weighting point. Each alternative requires a different infrastructure which affects the supply of sugar cane for milling. The case study was applied to a sugarcane mill of a corporation located in Sao Paulo State. By means of discrete simulation, we found that eighteen alternatives to configure D&H were feasible. By using the swing weight method in MCDA, we found that the fleet cost was the most important, while the alternatives with external D&H showed the best utility values. In the specific case, the best alternative is to use 28 road train (truck and two semi-trailers), 12 extra semi-trailer sets and 6 tractor units with external D&H strategy.

Analytical method for compiling and applying a ballast map for the traction unit PE2U

Under practical operation, electric locomotive traction units of series PE2U quite often require, especially in recent decades, various kinds of repair, necessitating the restoration of fleet of these machines that are rather worn-out. That changes the most important indicator in the work of the machine ‒ the distribution of masses; the resulting imbalance of the machine can reach 30 %. Further operation of such a locomotive leads to a decrease in its traction by 40‒100 kN, shortens the service life of the undercarriage by 8‒10 years on average, as well as requires that the speed of the machine during operation should be reduced by 10‒15 km/h. Given the lack of an appropriate regulatory framework and of recommendations in the specialized literature, such balancing operations are actually performed iteratively, with an arbitrary arrangement of ballast elements, which often delays the duration of operations and leads to their poor quality. One of the possible solutions to resolve this issue is the development and implementation of a special theoretical method that would make it possible to analytically substantiate the proposed structural-technological solutions related to the arrangement of a ballast at the electric locomotive traction unit PE2U. In this case, the ballast is composed of individual small-size elements that are stacked in rows into existing structural cavities in a bearing frame. The result is a compiled so-called individual ballast map for each machine. The proposed approach includes two stages of calculations and makes it possible to not only obtain practically acceptable ballast location diagrams, but to also significantly reduce the number of weighings required for the machine. The approach has been tested on several machines at electric locomotive traction units of PE2U over 2010‒2012 and could be officially used in the specialized regulatory documentation. Its practical error does not exceed 3 % and is mainly predetermined by technological factors

CHOOSING THE SYSTEM OF LOCOMOTIVE MAINTENANCE IN VIEW OF THE EFFECT OF DEPENDENT FAILURES

Purpose. Improving the efficiency of the use of locomotives by choosing a rational maintenance system that takes into account the assessment of the effect of dependent failures on the cost of their life cycle is the main purpose of this paper. Methodology. The relevance of introducing LCC (Life Cycle Cost) approaches in locomotive facilities is explained by the introduction of new locomotives with on-board control and diagnostic systems, as well as the development of the theory of traction rolling stock maintenance systems. The cost of a locomotive as a traction unit ceases to be the determining factor. This is because the locomotive maintenance and repair cost for the entire period of its operation is much higher than the initial cost of the locomotive. The paper analyses the existing approaches to managing the cost of the life cycle of locomotives at the stages of selecting, updating, upgrading and operating the traction rolling stock. The necessity of improving the methods for assessing the degree of influence of reliability indicators of locomotive assemblies on the choice of the maintenance system and the cost of the locomotive life cycle is substantiated. Findings. It is proposed to use the concept of «the effect of dependent failures» when calculating the cost of locomotive renewal after unscheduled repairs and its life cycle cost. We improved the methods for determining the cost of unscheduled repairs, taking into account dependent failures and the coefficient of assessment of the effect of dependent node failure on the locomotive maintenance system. The proposed coefficient will determine the nodes, the failure of which affects the renewal cost more than their nominal value. It will also help to take into account the probable losses due to node failure during the development and adjustment of the locomotive maintenance system. Originality. For the first time, it is proposed to use the concept of the effect of dependent failures to calculate the locomotive renewal cost when performing unscheduled repairs, as well as the locomotive life cycle cost. Practical value. The improved calculation method for determining the cost of unplanned repairs with account taken of dependent failures can be used to compare and evaluate different variants of the locomotive maintenance system and to develop the locomotive diagnostic systems.

Marathon2Operation, a Shift2Rail project for radio communication and simulation of train dynamics for distributed power within long trains

The paper reports the main objectives of the European research project Marathon2Operation (M2O). This project aims to define the best train configurations with distributed traction and communication via GSM-R radio technology, compared to longitudinal dynamics and to demonstrate their safety through a safety analysis independently assessed. The analysis involves trains with two up to four traction units. The trains analyzed are randomly composed, considering different types of wagons and different mass distributions along the train, to be representative of the operational reality. The first results of the project allow identifying some families of distributed traction trains (these are coupled trains) that have a behavior of longitudinal dynamics (also considering the degraded operation, i.e. with radio problems) similar to that of some trains currently running.

Assessment of change in maintenance of railway vehicles

Change is a concept that has always accompanied humanity, but at the same time – is underestimated in the context of introducing changes in various types of enterprises. This also applies to railway undertakings, which have recently been allowed to shape (change) the manner of maintaining passenger and traction railway vehicles. The article presents a literature analysis concerning the problem of change management and the railway regulations in force in this respect. Then, an exemplary assessment of the significance of change in maintaining the electric traction unit is shown.

Evaluation and improvement of town-coupled quality of vehicle based on the application target function connecting electrical and mechanical characteristics

Theoretical studies on the problem of increasing the traction force of a locomotive are analyzed and summarized. The complex nature of the process of interaction between the wheel pair and the track gauge, the changes in the parameters of the crew during the operation, the need to satisfy a number of contradictory constructive decisions and the choice of compromise solutions, requires the use of an effective criterion that will evaluate the options and determine rational solutions for achieving the maximally realizable thrust force efficiency and competitiveness of the traction unit. Static and dynamic redistribution of loads from wheel pairs to rails when the traction force is realized, the difference in the conditions for the interaction of individual wheel pairs with rails, the discrepancy between the characteristics of the engines and a number of other factors negatively affect the total maximally realizable thrust. The method of increasing the traction-coupling qualities based on the objective function is developed to estimate the reserve of realization of the total traction force of the locomotive wheel sets taking into account the integrated approach to the analysis results of the locomotive's design parameters and operational factors.

BEZPIECZEŃSTWO TRANSPORTU KOLEJOWEGO

Kolejowy transport zbiorowy jest obecnie w Polsce jedną z bardziej dynamicznie rozwijających się gałęzi. Wzrost liczby obsłużonych pasażerów, którzy korzystają najczęściej z pociągów, elektrycznych zespołów trakcyjnych czy też szynobusów, powoduje, że wzrastają także zagrożenia zaliczane do szeroko rozumianego bezpieczeństwa publicznego. Dotyczy to zarówno bezpieczeństwa w pojazdach ruchomych, jak też w obiektach stacjonarnych (np. stacje kolejowe, perony, przejścia podziemne pomiędzy peronami, itp.). Dlatego też tak istotne staje się stosowanie nowoczesnych elektronicznych systemów bezpieczeństwa, które mają na celu wykrywanie i zapobieganie zdarzeniom niebezpiecznych.

The new design of the vacuum circuit breaker mounted on the roof of Electric Traction Units

The new design of the vacuum circuit breaker mounted on the roof of Electric Traction Units

Simultaneous Drilling, Completions Concept Hopes To Extend Drilling Distances to 30 km

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 178859, “Long-Reach Well Concept,” by Sigmund Stokka, SPE, Eric Cayeux, SPE, David Gardner, SPE, Steinar Kragset, Hans Petter Lohne, SPE, Erlend Randeberg, Hans Joakim Skadsem, and Bjarne Aas, IRIS; Henrik Kyllingstad, Hole in One Producer; Torgeir Larsen, Wintershall; and Arild Saasen, SPE, Det Norske Oljeselskap and University of Stavanger, prepared for the 2016 IADC/SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 1–3 March. The paper has not been peer reviewed. Current extended-reach-drilling (ERD) well technology limits the well lengths to approximately 12 km, with a horizontal departure of approximately 10 km. This paper presents a concept that enables simultaneous drilling and completion, with an aim to extend well reach substantially and with an ultimate objective of constructing 30-km-long production wells. Longer-reach wells can be used to drain remote reserves using existing production facilities and to provide a means to access reservoirs located beneath environmentally sensitive areas. Concept Description The concept introduces a new way of constructing production wells. During drilling, the annulus is closed by packers and the well is drilled to the final target with one hole diameter. A steerable drilling module performs the drilling operation. A dual-wall casing replaces the drillstring and enables the drill cuttings to be transported to surface inside the inner casing. The string does not rotate during drilling but is pulled forward by a multiple-traction system com-posed of traction modules tentatively spaced at 120-m intervals along the drillstring. Tools for well completion, such as sand screens, sensors, and control systems, are integrated into the dual-wall casing. Fig. 1 shows an illustration of the tool string with two dual-traction units spaced with an intermediate-casing section. Dual-traction units are required to maintain zonal isolation at all times and to enable the string to move smoothly and continuously into the ground as drilling progresses. System Description This project investigated two versions of the concept: a casing-drilling system sized for 12¼-in. hole and a liner-drilling version deployed on drillpipe for an 8½-in. hole size. Recently, the project has focused primarily on the liner version. The developed solutions, however, are applicable to both versions. The liner concept provides a liner-drilling solution able to extend the well from a pre-existing production-casing-shoe depth. The liner assembly that can be deployed will be limited by the depth of the production-casing shoe and, thus, can enable the construction of wells up to perhaps 20 km in length. The liner is deployed using standard drillpipe; therefore, conventional rig equipment can be used for the drilling/completion operations. In contrast, the full production-casing-drilling concept can drill deeper wells but will require considerable modifications to topside facilities. The main components of the liner system are a pipe-in-pipe circulation system and multiple hydraulically powered traction units to overcome mechanical friction and provide weight on bit. The liner system is deployed on drillpipe using a running tool that channels the mud supply and cuttings returns in addition to connecting data communication between the surface and bottomhole assemblies (BHAs).

Novel analysis methods of dynamic properties for vehicle pantographs

Transmission of electrical energy from a catenary system to traction units must be safe and reliable especially for high speed trains. Modern pantographs have to meet these requirements. Pantographs are subjected to several forces acting on their structural elements. These forces come from pantograph drive, inertia forces, aerodynamic effects, vibration of traction units etc. Modern approach to static and dynamic analysis should take into account: mass distribution of particular parts, physical properties of used materials, kinematic joints character at mechanical nodes, nonlinear parameters of kinematic joints, defining different parametric waveforms of forces and torques, and numerical dynamic simulation coupled with FEM calculations. In this work methods for the formulation of the governing equations of motion are presented. Some of these methods are more suitable for automated computer implementation. The novel computer methods recommended for static and dynamic analysis of pantographs are presented. Possibilities of dynamic analysis using CAD and CAE computer software are described. Original results are also presented. Conclusions related to dynamic properties of pantographs are included. Chapter 2 presents the methods used for formulation of the equation of pantograph motion. Chapter 3 is devoted to modelling of forces in multibody systems. In chapter 4 the selected computer tools for dynamic analysis are described. Chapter 5 shows the possibility of FEM analysis coupled with dynamic simulation. In chapter 6 the summary of this work is presented.

Reliability analysis of the traction unit of a shearer mechanism with response surface method

The paper presents a High order stochastic response surface method (HOSRSM) for reliability and reliability-based sensitivity analyses of transmission mechanism of a shearer in heavy and impulsive environments. Dynamic analysis is affected by several sources of uncertainty, and it is important to quantify their combined effect on performance of the mechanism in order to aid risk assessment, risk mitigation, and decision-making. A dynamic transmission model of the traction unit is established under the condition of low speed and impulsive load. A performance function is proposed to evaluate the system transmission accuracy. The effects of basic variables in HOSRSM are investigated on calculation efficiency and computation cost of system precision reliability. The results indicate that structure parameters of a sun gear are more sensitive than others. The tooth width is a more sensitive geometric parameter than the diameter of the center hole. The targets are proposed to manufacture and inspect the sun gear in traction unit for safety.

Influence of uneven distribution of coupling mass on locomotive wheel pairs, its tractive power, straight and curved sections of industrial rail tracks.

This article deals with the problems of unloading the axes of wheel sets of locomotives of industrial railway transport by the example of exploitation in conditions of open chasing works. Studies have established that the displacement of the center of mass of an open-pit locomotive depends primarily on the height of the center of gravity, the height of the location of the hook of the locomotive coupling over the rails and the slope of the track. Therefore, to increase the coefficient of utilization of the adhesive weight and to ensure rational operating conditions, it is necessary to provide an adjustable displacement of the locomotive’s center of mass taking into account the actual operating conditions, including when driving on rectilinear and curvilinear sections of the track. Analysis of calculation results showed that for the traction unit OPE1 when driving in traction mode in close to the extreme operating conditions, it is necessary to provide a constructive solution for displacement of the center of mass of the locomotive up to 0.5 m in the course of movement of the locomotive’s center of mass.

SELECTION OF RATIONAL PARAMETERS OF THE NOMINAL MODE OF ELECTRIC LOCOMOTIVES

Purpose. The railways of Ukraine have been operated the locomotives, which are both morally and physically obsolete. Therefore, to ensure the competitiveness of rail transport it is necessary to update the locomotive fleet, and first of all the fleet of electric locomotives, because electrified railways provide the greater part of passenger and freight traffic. In this connection it is of special importance to determine the optimum parameters of the nominal mode of electric rolling stock. The purpose of the work is to examine the features of solution of these problems with respect to electric locomotives. Methodology . Assuming that the limit values of traction force are determined by the conditions of wheel-rail grip, then the power of the nominal mode can be represented as the product of rated speed, estimated friction coefficient, train weight and the coefficients that represent the ratio of the estimated (starting) value of traction force to value of traction force the nominal mode and the ratio of the mass of the locomotive to the train weight. Since the mass of the train is not a constant value, there is always a surplus power of the locomotive fleet required for the mastering of a predetermined volume of transportations. Reduced overcapacity of the locomotive fleet can be achieved by introduction of the locomotives of different power, designed for driving trains of different weight that will result in increased completeness of the power use but also in difficulty in selecting of locomotives for trains in operation. The paper shows the method of calculating the optimum values of power, speed and traction force of the nominal mode. It presents the mathematical model of the relationship of traction rate, excessive capacity and power of the traction unit. Findings. It is proved that the power of the traction unit, the total fleet power requirement and the excess of power in absolute units are proportional to the speed of the nominal mode. To reduce the total power of the fleet when selecting the optimum power of the traction unit it is necessary to take into consideration the speed of the nominal mode, defined by the condition of minimization of power consumption for traction, i.e. the smallest value that enables the implementation of the given running speed and the power redundancy level required for operation. Originality. It consists in the development of a unified algorithm for determining the optimal parameter values of the nominal mode of passenger, freight and freight-passenger electric locomotives. Practical value. The authors determined the minimization costs during production, acquisition and maintenance of electric locomotives, whose nominal mode parameters are designed according to the above procedure.

Draft Deployment of Traction Units with Active Tilting System for Regional and Long-distance Transport on Non-modernized Railway Tracks

The paper presents the perspectives of suburban traction units with tilting system particularly in regional transport to decrease the travel times and increase the competitiveness of railway transport. It aims to outline the importance of its use in this mode of transport, especially in the case when the condition of infrastructure is unable to provide higher efficiency possibilities for railway enterprises and investments for tracks optimization are not available or insufficient, i.e. enterprises cannot be more efficient in utilization of classic traction units of conventional design. The paper is focused especially on using traction units with tilting system within a selected regional transport section when analyzing the operational and technical characteristics and comparison of time savings after these units deployment.

Лубрикация рельсов тяговым локомотивом в составе поезда

Interaction of rolling stock and track is a fundamental physical process while running cars, locomotives and trains on the railway. The Research, Design and Technological Institute of the rolling stock (JSC VNIKTI) for more than twenty years conducting research to reduce cost of energy for traction.The Institute has developed rail lubrication technology performed by locomotive leading the train, but with the improvement: the lubrication of the internal rolling surface of the rail in curve performed by leading locomotive and on sections where lubrication made on side surface of the head of the outer rail - by lubricating cars. This technology can reduce the side impact of the rolling stock on the railway track in curved sections, to reduce resistance to motion while maintaining the length of the braking distance. The effect of reducing the side impact to the track is achieved by reducing the coefficient of friction on the rolling surface of the inner rail and the side surface of the outer rail, which leads to a proportional reduction of transverse forces of creep. Such reduction of transverse forces in creep decreases the normal reaction at the flange of the oncoming wheel and, consequently, reduces motion resistance (reduction in energy consumption for traction), reduce wear, both wheel flanges of rolling stock and rails in curves.Lubrication of rail by traction unit in the train has a broad perspective of application on the railway network of JSC Russian Railways. The minimum cost of additional equipping locomotives with devices automatically applying friction modifiers and manufacture of friction modifiers will payback considerable profit by savings of traction resources and by savings associated with a reduction in regrinding of wheelsets and replacement of rails in curves.

Development of dynamic base model of a bogie suspended forwarder

A forwarder is an off-road working machine that is used to transport logs from logging sites to a landing area that is accessible by trucks. Soil damage and operator comfort, especially whole-body vibrations when operating on hard and rough terrain, are crucial issues when developing novel forest machines. Most forwarders on the market are heavy machines with articulated steering and they are equipped with pairs of wheels mounted on bogies. For such bogie machines, only the flexibility and the dynamic dissipation in the tyres contribute to the “chassis damping”. The roll and lateral motions are the most severe components of the whole-body vibrations. So, developing new traction units, chassis suspensions and/or cabin suspension are in focus. Model-based design relies on focused models that are as simple as possible, but not too simple. This paper presents a 12 degrees-of-freedom multi-body dynamics simulation model of a standard eight-wheeled bogie type of medium-sized forwarder. The presented model is targeted for assessing and comparing different design solutions. It is shown that a configuration of seven rigid subsystems and eight flexible tyres represented with the simple and computer efficient Fiala tyre model enables the forwarder dynamic simulation model to be used to predict the roll and lateral motions of a forwarder operating on hard and rough terrain.

Dynamic reliability analysis for planetary gear system in shearer mechanisms

The paper considers the reliability and reliability-based sensitivity analyses of planetary gear systems in shearer mechanisms. It is important to quantify the dynamic performance of planetary gear system to aid in risk assessment and risk mitigation of the shearer mechanism. Failure of the system is defined as the dynamic contact stress exceeding the material strength within a time period. It is necessary to evaluate the cumulative failure event, which is defined as the combination of failure events at each time point. The method of saddle-point approximation (SPA) is introduced to evaluate the probability distribution of the equivalent maximum contract stress for the planetary gearbox. Additionally, reliability-based sensitivity indices are derived to investigate the parametric significance of random input variables. The gear transmission system of traction unit is used to demonstrate the engineering applications of the proposed method for dynamic reliability and reliability-based sensitivity analyses. A crude Monte Carlo simulation is performed to provide benchmark results. The results indicate that the structural parameters of the sun gear have more of an influence on system reliability than other parts of the mechanism.

Impact of the vibrations on the environment caused by passages of trains at variable speed

The paper deals with negative environmental impact caused by the passages of different kinds of trains at variable speed. The study is based on the measurement results which took place in Poland in 2013 on the railway line no. 4. The effect of the traction unit – Pendolino (EMU 250) on the vibration climate was analysed. The impact of passages of new trains was compared to currently operated rolling stock. The speed of trains was varying between 40 and 250 km/h. Vibration measurements were conducted by stuff of an accredited Laboratory of Structural Mechanics at Cracow University of Technology (Accreditation No. AB 826). The influence of the indicated vibrations due to passages of the trains on the building in the neighbourhood of the line was investigated. The vibration assessment was done for horizontal components of vibrations according to Polish standard code. Assessment of environmental impact was presented by indicator of perceptibility of vibration through construction (WODB), which refers to the Scales of Dynamic Influences (SDI scales). The limits specified by standards in any of the passages have not been exceeded. The change of speed or rolling stock resulted in a change in the characteristic of the vibration spectrum.

Motor Integrated Permanent Magnet Gear in a Battery Electrical Vehicle

This paper presents the physical construction and test results of two new demonstrators of a motor integrated permanent magnet gear (MIPMG), which is a second version of an already tested demonstrator. The demonstrators will be used as traction units for a battery electrical vehicle and the background for the specifications are elaborated. Simulated and measured results of rotational losses of the first and second versions are compared. The efficiency of the new design is investigated and compared with three direct-drive motors in a few operating points, and the MIPMG v.2 seems superior when used as a traction unit in urban traffic.