Train Vehicle Research Articles

Vehicle's lightweight design vs. electrification from life cycle assessment perspective

Lightwiegh materials and vehicles' electrification are among the most viable and economic solutions to improve fuel ecocnmoy of vehicles and reduce environmental impacts in the operational phase of typical vehicle's life cycle span. This study aims to shed more light on the combined effect of lightweighing and electrification by assessing different lightweight designs and electric powetrians from the environmental perspective using a life cycle analysis coupled with an emphasis on energy expenditures and carbon dioxide emissions. This paper discusses the life cycle assessment for several advanced powertrains namely; plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV) and hybrid electric vehicles (HEV) relative to the conventional gasoline operated internal combustion engine based power train vehicles. The main focus will be on the energy greenhouse gas emissions (GHG) in the material extraction and resources phase, manufacturing phase and use phase (operation and maintenance). While most of the current studies focus on the use phase that does not reflect the correct environmental impacts associated with advanced powertrains, thus the presented text applies a holistic LCA approach that covers pre-manufacturing, manufacturing, operational and end-of-life phases, plus another indirect phase to account for fuel extraction, refining and transportation to the end-users or customers. Based on the LCA emissions results, one may infer that environmental policies that reduce emissions rates from the electricity sector can mitigate this effect without completely eliminating it. Interestingly, the analysis show that lightweight vehicles with internal combustion engines have less impacts on the environment as a direct result of upstream emissions associated with electricity generation in United States. This scenario can differ in other countries with higher renewable and sustainable energy generated electric powers.

Design of distributed cooperative observer for heavy‐haul train with unknown displacement

Acquiring the relative displacement of adjacent vehicles when designing a distributed controller for a heavy-haul train is a critical issue. As heavy-haul trains run in complex, varying environments, the relative displacement of adjacent vehicles may not be measured accurately. To address this issue, this study proposes a distributed cooperative observer to estimate the relative displacement among train vehicles. First, a mass-point elastic-coupled dynamic model is constructed to capture the relative displacement of a heavy-haul train, and the complex model is further decomposed into a series of reduced double integrators. Then, a distributed cooperative dynamic observer is designed for each reduced double integrator. State information is shared via communication among neighbouring observers to accurately estimate the relative displacements of the vehicles under system noise. The convergence of the cooperative observer error is analysed using a Riccati equation. Finally, the performance of the closed-loop heavy-haul train control system combined with the cooperative observer is rigorously evaluated using real parameter settings of Shuohuang Railway in China.

A study on the wire reduction design and effect analysis for the train vehicle line

A study on the wire reduction design and effect analysis for the train vehicle line

Experimental Validation Of An Innovative Procedure For The Rolling Noise Correction

Among the wide contest of the train vehicles rolling noise evaluation, the aim of the paper is the development, implementation and experimental testing of a new method for roughness calculation according to FprCEN/TR 16891:2015 and the successive evaluation of the correction parameters of the measured rolling noise due to the presence of not compliant rail roughness. It is, in-fact, a very often operative condition, the execution of rolling noise tests over standard in-operation rails that are characterized by roughness profiles very different from standard one as those prescribed within the ISO 3095 procedure. Very often, this difference lead to the presence of an exceeding noise that needs to be evaluated and revised for a correct definition of the phenomena. Within the paper, the procedure implementation is presented and later on verified in operative experimental contest; forecasted and measured data are compared and successively commented.

2.6 GHz Intra-Consist Channel Model for Train Control and Management Systems

This paper presents a full characterization of the communications channel inside a train vehicle, in both narrow and wideband configurations. The purpose of this characterization is to be one of the first steps to check the feasibility of a wireless implementation of a train-control management system, a service which has been always carried over a wired network. Many different train topologies and scenarios have been taken into account in this paper (continuous and non-continuous train; train inside a tunnel, open-air or depot) and different results have been obtained (path-loss, angle of arrival, power-delay profile, and delay spread). The results show significant differences between continuous and non-continuous trains, and also highlight the importance of having a proper channel model with one slope per train car, instead of having only one slope for the whole train.

A Train-Bridge Dynamic Interaction Analysis Method and Its Experimental Validation

Abstract The train-bridge dynamic interaction problem began with the development of railway technology, and requires an evaluation method for bridge design in order to ensure the safety and stability of the bridge and the running train. This problem is studied using theoretical analysis, numerical simulation, and experimental study. In the train-bridge dynamic interaction system proposed in this paper, the train vehicle model is established by the rigid-body dynamics method, the bridge model is established by the finite element method, and the wheel/rail vertical and lateral interaction are simulated by the corresponding assumption and the Kalker linear creep theory, respectively. Track irregularity, structure deformation, wind load, collision load, structural damage, foundation scouring, and earthquake action are regarded as the excitation for the system. The train-bridge dynamic interaction system is solved by inter-history iteration. A case study of the dynamic response of a CRH380BL high-speed train running through a standard-design bridge in China is discussed. The dynamic responses of the vehicle and of the bridge subsystems are obtained for speeds ranging from 200 km·h−1 to 400 km·h−1, and the vibration mechanism are analyzed.

Frontal collision of trains onto obliquely stuck road trucks at level crossings: Derailment mechanisms and simulation

Road trucks stuck obliquely across rail tracks in level crossings and collided by trains are common occurrences; such scenarios are used in the assessment of crashworthiness of locomotives. With the ongoing increase in mass of the road trucks, these incidents can lead to derailment without fully exhausting the crush zones of the locomotives, especially in light passenger trains. Understanding the derailment mechanism of trains due to frontal collisions on stuck road trucks is fundamental for the development of advanced devices and/or technologies that can prevent these derailments. This paper presents a study of the dynamic responses and derailment mechanisms of trains for this scenario using a multi-body dynamics simulation method. A fully nonlinear three-dimensional dynamic model to simulate the frontal collision of a passenger train onto an obliquely stuck road truck on a ballasted track is formulated. This nonlinear model is capable of predicting the dynamic response as well as the derailment mechanism of trains. It is shown that the large lateral shift and yaw motion of the longitudinally coupled train vehicle bodies caused by the frontal impact force is the root cause of the derailments.

Combining Design of Vibration Absorbing and Isolation for a Power Equipment Based on 2 Degrees of Freedom

When power equipments are suspended under the under-frame of a rail train vehicles, dynamic and vibration characteristics of the car body will be changed. In order to study suspended parameters of the car body dynamic system, the vertical dynamic coupling model of rigid car body and power equipment under different exciting force was established. Results showed: when the exciting force of suspended power equipment is zero, the elastic suspension stiffness and damping can be designed according to the principle of Dynamic Vibration Absorber (DVA); when the exciting force acting on the rigid car body is zero, the vibration isolation problem of equipment is consistent to the base isolation problem, a good vibration isolation effect can be obtained as; when the body and power equipment simultaneously be excited, vibration absorbing and isolation must be simultaneously designed: the DVA is meet on at first, when ,the suspension isolation system appeared two different frequency peaks, but only , a good vibration isolation can be obtained for suspension system.

Evaluation of coupled finite element/meshfree method for a robust full-scale crashworthiness simulation of railway vehicles

The crashworthiness of a railway vehicle relates to its passive safety performance. Due to mesh distortion and difficulty in controlling the hourglass energy, conventional finite element methods face great challenges in crashworthiness simulation of large-scale complex railway vehicle models. Meshfree methods such as element-free Galerkin method offer an alternative approach to overcome those limitations but have proved time-consuming. In this article, a coupled finite element/meshfree method is proposed to study the crashworthiness of railway vehicles. A representative scenario, in which the leading vehicle of a high-speed train impacts to a rigid wall, is simulated with the coupled finite element/element-free Galerkin method in LS-DYNA. We have compared the conventional finite element method and the coupled finite element/element-free Galerkin method with the simulation results of different levels of discretization. Our work showed that coupled finite element/element-free Galerkin method is a suitable alternative of finite element method to handle the nonlinear deformation in full-size railway vehicle crashworthiness simulation. The coupled method can reduce the hourglass energy in finite element simulation, to produce robust simulation.

Vehicle detection from highway satellite images via transfer learning

Coming with the era of highway satellites, nowadays there is a massive amount of remote sensing images captured. Therefore, it is now feasible to detect vehicles directly from these satellite images, which has attracted extensive research attentions for both academic and industrial applications. However, it is not an easy task at all, mainly due to the difficulty to obtain training data to train vehicle detectors. On the contrary, there has been sufficient amount of labeled information regarding vehicle regions in the domain of aerial images. In this paper, we study the problem of detecting vehicles on highway satellite images, without the time-consuming step of collecting sufficient training data in this domain. Our key idea is to adopt a novel transfer learning technology that transfers vehicle detectors trained in the aerial image domain to the satellite image domain. In doing so, several cutting-edge vehicle detection algorithms can be directly applied. More specifically, our transfer learning scheme is based on a supervised super-resolution algorithm, which learns mutually correlative sparse coefficients between high and low resolution image patches. Then, a linear SVM based detector is trained, the loss function of which is integrated into the sparse coding operation above. Experimental results have shown that the proposed framework can achieve significant improvement over several alternative and state-of-the-art schemes, with high precision and low false alarms.

Multi-Point Co-Ordination Scheme for Traffic Control Systems

Traffic management is one of the severe setbacks in metropolitan life style and is acutely realized in all major cities due to different factors such as overpopulation, exploitation, ecological contamination and so on. This is mainly due to the fact that the rate at which the change in infrastructure observed is drastically slower than that of the increase in the number of vehicles owing to constraints related to the space and cost. Certain research works conducted on management of traffic using Traffic Classification Approach (TCA) improved the classification performance by including the correlated information to the classification process. But using correlated information though classification performance was improved, the flow correlation analysis was not performed in an effective manner resulting in increase of the time taken to classify. With the increasing traffic patterns, high degree of flexibility and dynamic traffic Failure Independent Path Protecting (FIPP p-cycles) provided provisioning for dynamic protection but compromising the QoS. With the introduction of additional traffic management instruments, congestions arise whenever different measures of management of traffic are applied in the similar area. In this paper a multi-proxy co-ordination mechanism is designed for effective traffic management using fuzzy correlation analysis (MPFCA). A multi-proxy based traffic junction points is proposed to control the overall framework for intellectual transportation systems. Multi-proxy Co-ordination is formed by analyzing the nearest and adjacent traffic junction points to generate a coordinated traffic signal controlling across the region. A fuzzy correlation analysis is introduced in MPFCA in order to obtain the property of traffic intelligence to the system to minimize the time taken to classify. By representing different measures as intellectual proxies, the measures of the individual mechanisms are synchronized. By synchronizing the neighboring traffic junction points, the process performs superior as a whole to improve the QoS. Experimental evaluation is made with multiple image data scenes obtained from the traffic signals of specific region and also with the benchmark training vehicle image data extracted from the machine learning repositories. The performance of the proposed multi-proxy co-ordination using fuzzy correlation analysis (MPFCA) is measured in terms of execution time.

Dynamic behavior of a simply supported bridge with a switching crack subjected to seismic excitations and moving trains

This paper presents a numerical solution for the dynamic response of a simply supported bridge with a switching crack subjected to seismic excitations and moving trains. The train vehicle is represented by a four degrees-of-freedom model, and the seismic excitation is exerted using the acceleration input. While the crack state remains constant, the bridge vibration is evaluated through a modal analysis. When the crack is switching, the equilibrium position is taken into account to analyze the change of the displacement components. The proposed method is used to study the response characteristics of a numerical bridge, and the results show that under the independent action of seismic load, the equilibrium position changes suddenly at the switching instant and an added vibrational displacement appears. Finally the vibrational displacement is increased by the crack switching and the vibration amplitude becomes larger. Under the combined action of the seismic excitation and the train, the equilibrium position is shifted down, and the effect of the added displacement is reduced. So the vibration amplitude is smaller under the combined action than under the independent action. Meanwhile, the amplitude also is affected by the train weight and velocity.

Pedestrian Safety at Rail Grade Crossings: Focus Areas for Research and Intervention

Contrary to the declining number of fatalities due to train–vehicle collisions at highway-rail grade crossings, the number of pedestrian and bicycle fatalities at highway- and pathway-rail grade crossings has increased in the last dozen years. While engineering solutions and education and enforcements initiatives have been proposed and implemented, little is known as to their effectiveness to mitigate such incidents. This paper reports on findings from the literature and discussions with professionals in the public and private sectors involved in safety at rail grade crossings. Major areas found in need for improvement include (a) advancing consistent standards for warning devices and treatments; (b) advancing consistent approaches for managing non-motorist risk; and (c) continuing commitment to education, engineering, enforcement, and evaluation efforts by enabling stakeholders to provide adequate resources. The paper highlights the multitude of factors related to pedestrian safety in this context, and provides an informed discussion for researchers and practitioners involved in advancing safety initiatives.

Distribution of Longitudinal Forces in the Body of Passenger Trains

The distribution and the size of longitudinal dynamic forces that develop in the train body found in braking system are influenced by the length of the train. To determine these forces, it is used a mechanical model consisting of rigid bodies, representing the train vehicles, connected by elastic and damping elements with the nonlinear characteristic that shapes the buffer and draw-gear. The results based on numerical simulations highlight the emergence of dynamic longitudinal forces during braking, their evolution over time and the distribution of maximum compression and stretching forces that develop in buffer and draw-gear devices, for different lengths of the passenger train.

열차하중, 속도변화에 따른 토공상 콘크리트 슬래브궤도의 거동특성연구

In recent high speed rail way, the operating speed of train is enhanced and the introduction of EMU train vehicles is increased. In addition, as expected the demand of the concrete slab track and the trend of design cross-section reduction, the clear behavior of evaluation of internal slab layer is demanded about the variation of design load and speed. The purpose of this study is to evaluate and identify the mechanical behavior pattern of concrete slab track and track-road bed with the variation of axle load and train speed. To this end, the behavior of TCL and HSB was evaluated in according to the variation of axle load and speed. And the analysis results and the data measured TCL strain sensor, which was embedded in TCL slab under installation on Honam high speed railway, was analyzed. The analysis result shows that the strain are increasing in according to the speed-up of train, and line regression was obtained from measured data. Analysis data of the state of bonding condition of slab layer and measured data was analyzed. It is conducted that the TCL layer stress of HEMU 430X, which of axle load, is lighter was similar to the stress of KTX-Honam, the standard deviation of measured stress is dramatically increased.

Failure Analysis of Train Vehicles Engagement Arm

This paper studies the failure reasons of train vehicles engagement arm. The arm ends with screw. From the statistical observation, it is found that the failure always happens in the screw region. The steel used in this engagement arm is carbon steel of 0.40C–0.26Si–0.68Mn–0.068Cr chemical composition in wt.%. The non-metallic inclusions were followed and studied in the screw profile (root, flank, and matrix) using optical and SEM microscope. The tensile testing was carried out to compare with the standard values. Optical microstructure reveals ferrite-pearlite bands. EDS-SEM revealed that the segregation of Mg in the non-metallic inclusions creates micro-shrinkage porosity around the non-metallic working as stress concentrators during the service leading to catastrophic cracks.

Genetic Counseling Supervisors' Self-Efficacy for Select Clinical Supervision Competencies.

Supervision is a primary instructional vehicle for genetic counseling student clinical training. Approximately two-thirds of genetic counselors report teaching and education roles, which include supervisory roles. Recently, Eubanks Higgins and colleagues published the first comprehensive list of empirically-derived genetic counseling supervisor competencies. Studies have yet to evaluate whether supervisors possess these competencies and whether their competencies differ as a function of experience. This study investigated three research questions: (1) What are genetic counselor supervisors' perceptions of their capabilities (self-efficacy) for a select group of supervisor competencies?, (2) Are there differences in self-efficacy as a function of their supervision experience or their genetic counseling experience, and 3) What training methods do they use and prefer to develop supervision skills? One-hundred thirty-one genetic counselor supervisors completed an anonymous online survey assessing demographics, self-efficacy (self-perceived capability) for 12 goal setting and 16 feedback competencies (Scale: 0-100), competencies that are personally challenging, and supervision training experiences and preferences (open-ended). A MANOVA revealed significant positive effects of supervision experience but not genetic counseling experience on participants' self-efficacy. Although mean self-efficacy ratings were high (>83.7), participant comments revealed several challenging competencies (e.g., incorporating student's report of feedback from previous supervisors into goal setting, and providing feedback about student behavior rather than personal traits). Commonly preferred supervision training methods included consultation with colleagues, peer discussion, and workshops/seminars.

Trajectory tracking for uncertainty time delayed-state self-balancing train vehicles using observer-based adaptive fuzzy control

Complex systems, such as the interconnected self-balancing vehicles system, are known to be highly nonlinear, under-actuated, and challenging to control. Their complexity is further increased by the presence of time delays and external disturbances. Therefore, all attempts to control the interconnected self-balancing vehicles system were based on accurate determination of its states. However, it is well known that modelling of interconnected self-balancing vehicles systems is not an easy task. In this paper, trajectory tracking of a series of two-wheeled self-balancing vehicles, named B2-train system, is addressed. The highly nonlinear under-actuated system is analyzed and a nonlinear dynamic model of the B2-train system is derived using the Lagrangian method. The adaptive fuzzy controller is designed to approximate the unknown system parameters under the constraint that only the system output is available for measurement. To address this the constraint, a nonlinear state observer is employed to estimate the states including time delays. The aim is to design a state observer-based adaptive fuzzy controller using variable structure (VS) technique and a time delayed compensator which ensures the robust asymptotic stability of the closed-loop system and guarantees an H∞ norm bound constraint on disturbance attenuation for all admissible uncertainties based on Lyapunov criterion. Finally, a time-delayed B2-train system with 2 vehicles is used to demonstrate the performance and robustness of the proposed control scheme.

Domain adaption of vehicle detector based on convolutional neural networks

Generally the performance of a vehicle detector will decrease rapidly, when it is trained on a fixed training set but applied to a specific scene with view changes. The reason is that in the training set only a few samples are helpful for vehicle detection in the specific scene while other samples disturb the accurate detections. To solve this problem, we propose a novel transfer learning method to adapt the trained vehicle detector based on convolutional neural networks (ConvNets) to a specific scene with several new labeled samples. At first we reserve the share-filters and update the non-shared filters to improve the sensitivity of the vehicles in the specific scene. Then we combine the similar feature maps to accelerate the detection speed. At last for making the vehicle detector stable, we fine-tune it several times with the updated training set. Our contributions are an original research on transferring the vehicle detector based on ConvNets and an optimization approach about removing the redundant connections in the ConvNet vehicle detector. The extensive comparative experiments on three different datasets demonstrate that the transferred detectors achieve the improvements on both of the accuracy and speed.

ABOUT THE EVALUATION OF THE LONGITUDINAL FORCES LEVEL EFFECTING THE TRACK DISPLACEMENT AT TRANSIENT MODES OF TRAIN MOVEMENT

Purpose. Study the transient modes effect of movement on the track displacement for the freight train safety control is supposed in this paper. For this it is necessary to investigate the longitudinal dynamics of a train on the track displacement. Simultaneously to assess the longitudinal forces level of a track and rolling stock interaction. Methodology. The level of the longitudinal forces, effecting the track displacement, was evaluated using mathematical modeling of longitudinal vibrations of the trains at transient modes of motion caused by braking. It was considered that each train vehicle consists of a body (solid) and the wheel sets, connected with the body by friction bearings (inelastic link). It was believed that during the movement of each train vehicle the vertical plane of its symmetry coincident with the vertical plane of symmetry of the assembled rails and sleepers. At simulation it was also supposed that in the process of translational motion of the vehicle body wheels make pure rolling along the rail without slipping on it. Findings. In the results of calculations the values of the longitudinal forces at different types of braking were obtained (it is regenerative braking and pneumatic one) under quasi-static and shock transients. For this various initial state of clearances in the inter-car connections up to beginning of transient was considered. The level of dynamic additives to longitudinal forces of interaction between wheel and rail that are substantially depending on vehicle accelerations was assessed. Originality. The transient regimes effect of trains movement caused by braking on the level of the longitudinal forces of track and rolling stock interaction was investigated. The longitudinal load of freight trains with regenerative and pneumatic braking was researched. The effect of the initial state of the train and different modes of braking on a dynamic additive to the longitudinal forces of the interaction between the track and rolling stock, which may effect the displacement of assembled rails and sleepers, was estimated. Practical value. The obtained results can be used to select rational modes of braking of freight trains, especially on lengthy down grade, from the positions prevent possible track displacement.