Wheel Set Research Articles

Gauge widening of passenger coach wheel sets in Indian Railways: Observed statistics and failure analysis

Abstract Several hundreds of gauge widening cases have been reported in coaching stock wheel sets of Indian Railways over the last two years. This work investigates the effect of non-uniformity in braking, brake load, braking frequency, wheel profile, and braking cycles on wheel gauge evolution in coach wheel sets with an aim to identify root cause of the problem. A validated finite element model considering heat generation at brake-wheel interface, heat partitioning at wheel-brake block and wheel-rail interfaces, and convective, radiative heat loss to ambient air is used to estimate wheel temperatures, stresses, and gauge change. Residual stresses generated during wheel manufacturing and fitment of wheel onto axle are considered in the study. It is found that wheel gauge reduces during braking and increases as wheels subsequently cool down. Magnitude of temporary gauge reduction and permanent gauge widening increases with increasing heat input. Thus, higher non-uniformity in braking – leading to overheating of some wheels – can cause wheel gauge widening. Interestingly, reduction in brake load reduces permanent gauge widening but increases temporary gauge reduction during braking. Nature of gauge change and effect of wheel profile, seen from gauge widening statistics, correlate well with findings from simulations.

Estimation of vibration attenuation coefficient of wheel sets on electric locomotive underframe

The work objective is to describe the theoretical and experimental research of the vibration attenuation coefficient of the wage wheels on the electric locomotive underframe. Studying the vibro-acoustic characteristics at the workplaces of the locomotive crews shows that the excess of the octave sound-pressure levels over the maximum permissible values is largely determined by the noise structural component which is generated by vibrations of the body parts. The vibration velocity calculation is based on the energy methods traditionally used for the energy-closed circuits. The system of equations takes into account not only the geometric parameters of the elements, their physical and mechanical properties, but also the vibration power from the locomotive wheel pairs introduced into the base body under the speed conditions. For the engineering analysis of the vibration spectra of the body parts, and, respectively, of the sound-pressure levels when evaluating the introduced vibration power, it is expedient to use a frequency dependent value of the vibration reduction factor. This is especially important at the machine designing stage. Therefore, the results of the experimental study of the given value and the development of the regressional dependences for various motion speeds on this basis are presented.

Finite Element Analysis and Experimental Study on Failure Rolling Bearing

As the most important component of moving parts in the wheel set system, the rolling bearings’ performance is the key to the safety of locomotive running. In this paper, the finite element model of rolling bearing with fault of inner ring stripping was established in ABAQUS, the first twenty orders of natural frequency and mode characteristic was analyzed. The highest frequency was used as the center frequency of the band pass filtering in the process of resonance demodulation and this technique was validated with simulation. Then fault vibration signal of rolling bearing was collected using wheel set running-in test bench and was analyzed with this method, the comparison proved that the simulation and test results basically tallied.

State Inspection and Fault Diagnosis System of Train Axel Box Bearing Based on Virtual Instrument

Fault diagnosis of train bearing is an important method to ensure the security of railway. In the paper, four time domain statistical analysis methods and resonance demodulation method as a frequency domain analysis method are introduced. A state inspection and fault diagnosis system of train axel box bearing is constructed and its efficiency is also tested by wheel set experiment.

Vibration control of a semi-active railway vehicle suspension with magneto-rheological dampers

This article presents vibration control performances of a semi-active railway vehicle suspension system using a magneto-rheological damper tested on the roller rig. In order to evaluate control performances, a mathematical railway vehicle model with 15 degrees of freedom is first derived to represent the lateral, yaw and roll motions of the car body, bogie frame, and wheel set, respectively. Based on the formulated model, the design parameters of magneto-rheological damper are determined to undertake a compatible comparison with dynamic performances of conventional (existing) passive railway vehicle suspension system. The designed magneto-rheological damper is manufactured and its field-dependent damping force characteristics are experimentally evaluated. Subsequently, in order to enhance the ride quality of a railway vehicle suspension equipped with magneto-rheological damper, a skyhook controller associated with an extended Kalman filter is designed in a state space representation. The railway suspension system incorporated with the car body and two bogies is then experimentally set up on the roller rig in order to evaluate the ride quality. It is demonstrated from experimental realization of the controller that the ride quality of the suspension system with magneto-rheological damper can be significantly enhanced compared with the existing passive suspension system.

Finite element modeling for structural strength of quadcoptor type multi mode vehicle

Quadcoptor (QD) type multi mode vehicle is modeled for the structural strength using finite element method (FEM). Static as well as dynamic mass and stiffness matrix were developed for key component of such vehicle that includes base plate, mounting frame, arm, support frame, propeller and wheel set. The components, thus generated are preprocessed for meshing, material selection, constraining, loading. The boundary condition is set and mesh convergence is tested before solving the model. The results, such as deformation, von Misses stress are analyzed for each component as well as for the upper half of the multi mode vehicle. The results depict the critically stressed zone of various key components of QD.

Dynamic response of high-speed rails due to heavy braking

The dynamic response of a high-speed rail experiencing heavy braking is investigated using the moving element method. Possible sliding of train wheels over the rails as the train decelerates is accounted for. The train is modelled as a 14-DOF system comprising a car body, bogies and wheel sets interconnected by spring-damping units. The railway track is modelled as an infinite Euler–Bernoulli beam resting on a two-parameter elastic-damped foundation. A convected coordinate system attached to the moving train is employed in the formulation of the governing equations. The effects of braking torque, coefficient of static friction between wheels and rail, initial train speed and the severity of railhead roughness (track irregularity) on the dynamic response of the high-speed rail, including the occurrence of the ‘jumping wheel’ phenomenon, are examined. The phenomenon describes the momentary loss of contact between the wheel and track. A combination of high braking torque, large static friction coefficient, high initial train speed and severe track condition promotes larger dynamic effects.

Vision‐based fault inspection of small mechanical components for train safety

With the development of both hardware and software technologies in camera and computer, automated visual inspection system is being used more and more in intelligent transportation system for its high efficiency. For the safety operation, it is necessary to perform fault inspection for train mechanical components. As one of the most widely used small mechanical components in freight trains, bogie block key (BBK) is used to keep wheel sets from separating out of bogies, and its fault is likely to cause terrible accidents. This study proposes a vision-based system to inspect the missing of BBK automatically. To ensure accurate and rapid fault inspection, a hierarchical detection framework consisting of fault area extraction and object detection is proposed. The purpose of fault area extraction is to divide image regions which contain the inspected component from the complex background. Subsequently, a component detector based on the sparse histograms of oriented gradients and support vector machine is proposed to verify the candidate image regions to check whether the BBK is missing or not. The experiments show that the proposed system realises the status inspection of BBK with high accuracy and high speed and can meet the need of actual applications.

DYNAMIC FEATURES OF STANDARD TANK CARS ON CURVED TRACK SECTIONS

[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT Nature of interaction of wheel sets of four-axle and eight-axle tank cars with rails when driving in curves of railway track is considered, including specifics of longitudinal and transverse elastic ties of wheel sets with bogie’s side frames. The results of dynamic performance studies (coefficient of dynamic addition of vertical forces on sprung weight and transverse frame force) of tank cars in curves with radii of 350 and 650 m are provided. It follows that eight-axle tank car design under the terms of traffic safety from the point of view of dynamics is at the same level as a four-axle one, therefore, can be used without restriction on all railways under the same rules of maintenance for undercarriages of tank cars of both types. Keywords: railway, theoretical mechanics, tank car, wheel sets, rails in curves, dynamic performance, elastic and frictional bonds, unextinguished transverse acceleration, coefficient of dynamic addition of vertical forces, frame force, comparative analysis. REFERENCES 1.Verigo, M. F.Interaction of track and rolling stock in curves of small radius and the fight against side wear of rails and wheel flanges [Vzaimodejstvie puti i podvizhnogo sostava v krivyh malogo radiusa i bor’ba s bokovym iznosom rel’sov i grebnej koljos]. Moscow, PTKB CP MPS publ., 1997, 207 p. 2. Anisimov, P. S. Methods of Evaluation of the Impact of Freight cars on the Track. World of Transport and Transportation, Vol.12, 2014, Iss.1, pp.24-32. 3.Vershinskiy, S.V., Danilov, V.N., Khusidov, V. D. The dynamics of the car [Dinamika vagona]. Moscow, Transport publ., 1991, 360 p. 4.Anisimov, P.S., Zhelnin, G.G., Kulikovskiy, B. S. Permissible speed of eight-axle tanks dimensions TC [Dopuskaemye skorosti dvizhenija vos’miosnyh cistern gabarita Tc]. Trudy MIIT, 1986, Iss.780, pp.10-24. 5.Anisimov, P.S., Grachiova, L. O. Tests of eight-axle tanks for BAM [Ispytanija vos’miosnyh cistern dlja BAMa]. Zheleznodorozhnyj transport, 1986, Iss.5, pp.35-36.

MODELING OF DEVELOPMENT VERTICAL DEFORMATION OF RAILWAY TRACK

Purpose. State of railway track must meet the conditions of safety, comfort and smooth ride. The presence of irregularities deteriorates the dynamics of interaction of track and rolling stock, causes speed limiting, creates the possibility of movement safety violation. This brings up the question concerning the study of the factors leading to the possibility of track irregularities and the process of their development. The purpose of this paper is to analyse the processes of emergence and development of irregularities in the area of unequal vertical elasticity of railway track using mathematical modelling. Methodology. Railroad under the trains works as the system of elastic bodies, so the emergence and development of irregularities can be represented as the transition from elastic to permanent strain. Irregularity development will affect the dynamics of interaction between track and rolling stock not only at the wheel location directly in the area of irregularity, but also at a certain distance beyond. Therefore, to study the development of irregularities, including those along the track, it is necessary to model the process of wheel load movement along the area. The adopted model consists of a wheel set moving on inertia-free beam and resting on individual supports. It is described by Lagrange differential equations. The work introduced the hypothesis that the level of permanent strain is distributed in proportion to the dynamic deflection derivative. Findings. Location of vertical longwise irregularity does not necessarily reproduce the location of the problem area. While in operation the vertical irregularity extends not only in depth but also along the track, herewith the increase in length is accompanied by the displacement of local maxima and the emergence of new ones. This leads to the development of so-called «pits» when approaching unequal-elastic areas. Originality. The work provides further development of tasks for track and rolling stock interaction modelling, in particular aimed to take into account the unequal elasticity areas and their influence on the formation of the track irregularities. The paper proposes new approaches to modelling the transition from elastic to permanent strain that allows predicting the development of track irregularity sizes depending on the area characteristics. Practical value. The results obtained by the author can be used to determine the schedule for track equal elasticity renovation works, as well as to analyse the measures aimed at the prevention of irregularities in areas with variable elasticity of railway track.

Track Section Occupancy Detection Model Based on Infrared Ray Sensor and Time-Series Change Rate Matching

Track section occupancy detection is one of the key problems in the field of railway transportation and train dispatching, which has strong link with the safety of railway traffic. In order to reduce the cost and improve the accuracy of track section occupancy detection, this paper presents an algorithm based on infrared ray sensors and the time-series change rate matching. Once a train passes, the infrared ray sensors installed on both sides of the track collect the signal time-series of a wheel set where various noises exist. This paper makes use of the similarity between the change speed and the acceleration of the standard time-series and the time-series collected to realize the similarity matching and noise recognition, which can infer the direction of the running train and the number of its wheel sets by analyzing and judging the signal time-series and finally achieve the task of track section occupancy detection. The simulation data and field test results demonstrate that the proposed algorithm improves the accuracy, availability, and reliability of track section occupancy detection based on infrared ray sensors, with a correct rate up to 99.999%.

Numerical analysis of the dynamic interaction between wheel set and turnout crossing using the explicit finite element method

ABSTRACTA three-dimensional (3-D) explicit dynamic finite element (FE) model is developed to simulate the impact of the wheel on the crossing nose. The model consists of a wheel set moving over the turnout crossing. Realistic wheel, wing rail and crossing geometries have been used in the model. Using this model the dynamic responses of the system such as the contact forces between the wheel and the crossing, crossing nose displacements and accelerations, stresses in rail material as well as in sleepers and ballast can be obtained. Detailed analysis of the wheel set and crossing interaction using the local contact stress state in the rail is possible as well, which provides a good basis for prediction of the long-term behaviour of the crossing (fatigue analysis). In order to tune and validate the FE model field measurements conducted on several turnouts in the railway network in the Netherlands are used here. The parametric study including variations of the crossing nose geometries performed here demonstrates the capabilities of the developed model. The results of the validation and parametric study are presented and discussed.

Stress Ratio Effect on Ratcheting Behavior of AISI 4340 Steel

Ratcheting is known as accumulation of plastic strain during asymmetric cyclic loading of metallic materials under non-zero mean stress. This phenomenon reduces fatigue life of engineering materials and thus limits the life prediction capacity of Coffin-Manson relationship. This study intends to investigate the ratcheting behavior in AISI 4340 steel which is mainly used for designing of railway wheel sets, axles, shafts, aircraft components and other machinery parts. The effect of stress ratio on the ratcheting behaviour in both annealed and normalised conditions were investigated for investigated steel. Ratcheting tests were done at different stress ratios of -0.4, -0.6 and -0.8. The results showed that the material responds to hardening behavior and nature of strain accumulation is dependent on the magnitude of stress ratio. The post ratcheted samples showed increase in tensile strength and hardness which increases with increasing stress ratio and these variations in tensile properties are correlated with the induced cyclic hardening.

Automated Visual Inspection System for Bogie Block Key Under Complex Freight Train Environment

With the development of hardware and software in camera and computing units, visual inspection system (VIS) plays an increasing significant role in fault inspection task. This paper proposes a VIS to inspect the missing of bogie block key (BBK) used on freight trains. BBK is an important component to keep wheel sets from separating out of bogies. The missing of BBK is one of the most common faults threatening the running safety. VIS first acquires a bogie image by the image acquisition system, and then a hierarchical inspection framework containing bearing cap (BC) detection, fault region localization, and BBK classification is proposed. Specifically, a cascaded detector trained by the AdaBoost approach combined with the gradient coded co-occurrence matrix (GCCM) features is used to achieve fast and accurate BC detection. Then, a fault region is located on the basis of the relationship between the BC and BBK. Finally, a BBK classifier based on the GCCM features and a support vector machine is used to process the fault region to identify the missing of BBK. The proposed system has been applied on a long sequence of real images showing high inspection speed and accuracy.

Smart Telematics Enabling Efficient Rail Transport – Development of the ViWaS Research and Development Project

Single wagonload (SWL) transport is a major component in European rail transport systems and in the logistics of different industrial sectors such as steel, chemical and automotive. However, changing framework conditions and increasingly demanding market requirements have led to dramatic losses of market share and even to complete shutdown of SWL business in some countries. As this business segment has been evaluated as an important component of the European co-modal transport system also in the future, significant improvements are needed. The ViWaS project develops and proposes solutions which contribute to a raised competitiveness of SWL in Europe.Unlike in road transport, load tracking and tracing is still not widely used in SWL. ViWaS seeks to accelerate the introduction of communication technology in rail freight. With on-board communication technology freight operators improve the dispatching of wagons and the rescheduling processes in case of disturbances. Based on reliable on-line telematics data, the dispatchers will be able to inform their customers about changes in the transport schedule earlier than today, increasing the reliability and satisfying the stakeholders.Cost-efficient and intelligent telematics-based information services enable real-time wagon tracking and automatically depict wagon mileage information. The telematics data service will generate the required information which is necessary for a reliable quality recording. With this additional information, the current life cycle of freight wagons of six years will be optimised. Since the accident of Viareggio, the railway authorities are requesting documentation of wagon mileage. A small electronic mile-counter with a-radio link to the telematics device RodoTAG® overtakes the RU's responsibility of wheel-set individual mileage counting. Based on long term experiences with NavMaster telematics, Eureka defined a list of requirements for the system design “small, lightweight and cost reducing”, resulting in a completely new system concept: The ViWaS telematics PCB is very small sized and equipped with a low power multi-GNSS (GPS, GLONASS, Galileo, QZSS and SBAS) circuit. With the new GSM and GPS modules, a significant cost reduction could be achieved, interfaces for complementing sensors as e.g. shock detection, digital/analogue inputs/outputs, etc. are integrated. In addition, based on the analysis of user requirements the development of a reliable load sensing technology for freight cars has been launched. This request is a result of the fact that today most of the freight cars in railway operation do not use the full load capacity as there is no existing cost-effective possibility to measure the load especially during the filling-up process e.g. in the area of bulk freight. If the wagon would be overloaded and afterwards moved by a train, all wheel sets have to be exchanged for a costly inspection in a workshop. Thus, the freight car will not be filled to its maximum payload resulting in reduced capacity and higher costs. In order to optimise the dispatching processes wagons will transmit their load status, enabling the dispatchers to re-dispatch the wagon in short time after unloading leading to shorter standstill times and higher wagon efficiency.

Development of a Cutting Tool for High-performance Cutting of Railway Rolling Components

High performance cutting (HPC) is used in machining railway parts like wheel sets or axes with large depth of cut and high feeds). The process is accompanied by increased thermal loads causing high concentration of stresses in the contact areas with the tool. This paper presents a set of methods to reduce thermal stress in machining zone in HPC conditions through the use of a special tool system, consisting of carbide cutting inserts with nano-structured multilayer composite coatings and a special scheme for mounting such inserts on tool holder with the use of high heat-conducting ceramic-polymer pads. The study has revealed that the developed tool system can significantly accelerate heat transfer from the insert and increase efficiency. Production tests show that the tool and the new coating in machining rolling stock (of railway) components can improve performance by 80-100%.

輪軸の蛇行動に関する考察

In order to obtain insight about weave phenomenon of wheel set of rail vehicle, this paper starts with formulating its natural frequencies and damping ratios. Interpreting these formulas, this paper points out that larger ratio of creep coefficient normalized by wheel set mass reduces the weave at lower speed than a given speed and the smaller ratio does it at higher speed.

Design and Fabrication of a Ball Projecting Machine

To make a ball projecting machine which pitches various kinds of balls either soft, leather, baseball or tennis ball at desired line and length as required. It can throw the ball at predetermined speed with required spin/swing effect. Problem with the existing machines is that they are very expensive and because of very low competition they ask for extremely huge price. The project began from the research phase with the identification of basic components used in the making of bowling machine. A thorough review of the theory and operations involved in a bowling machine were studied. A basic design was plotted and after review final design was made. Fabrication was done which involved operations on lathe, milling, grinding, welding machines etc. First 2 motors were coupled with the wheels, and then it was installed on a cylindrical bar which was installed on a base plate. A drive is used which is connected with the motors. The first worm and worm wheel set is installed on the rotating shaft on top of the base plate. Second similar set is installed at bottom. A power screw is welded at bottom which allows which fits inside a circular disc which carries corresponding threads. Its rotation about those threads would provide vertical lift and fall, also rotation in horizontal plane providing height adjustment and line change respectively. Finally three hollow cylindrical bars are welded at periphery of the circular plate holding power screw to form a tripod stand. The result is an efficient working bowling machine which is relatively much cheap in manufacturing. It could project the ball at various speeds with desired spin/swing effect. It also provides the facility to project various kinds of balls.

English

English

Vertical Track Irregularity Influence on the Wheel High-Frequency Vibration in Wheel-Rail System

A three-dimensional deformable finite element model of wheel-rail system is established. The vertical vibration natural frequencies are calculated by modal analysis. The improved central difference method by ABAQUS explicit nonlinear dynamics module is chosen to calculate the vertical vibration of wheel axle. Through the vibration measurement experiment ofLMAwheel by China Academy of Railway Sciences, the contact parameter is optimized and the model is modified. According to the nonlinear simulation results, the important influence of vertical track irregularity on the wheel set high-frequency vibration is discovered. The advantage frequencies through spectrum are close to the vertical vibration natural frequencies of seventh, eighth, ninth, and tenth mode. When the velocity is 350 km/h, system’s nonlinear dynamic characteristic is higher than the results at 200 km/h. The critical wavelength of vertical track irregularity on the wheel vertical vibration is about 0.8 m. In addition, a particular attention should be paid to one situation that the main dominant frequency amplitude is more than 50% of the acceleration amplitude even if the peak acceleration is low.