Locomotive Model Research Articles

Train energy simulation with locomotive adhesion model

Railway train energy simulation is an important and popular research topic. Locomotive traction force simulations are a fundamental part of such research. Conventional energy calculation models are not able to consider locomotive wheel–rail adhesions, traction adhesion control, and locomotive dynamics. This paper has developed two models to fill this research gap. The first model uses a 2D locomotive model with 27 degrees of freedom and a simplified wheel–rail contact model. The second model uses a 3D locomotive model with 54 degrees of freedom and a fully detailed wheel–rail contact model. Both models were integrated into a longitudinal train dynamics model with the consideration of locomotive adhesion control. Energy consumption simulations using a conventional model (1D model) and the two new models (2D and 3D models) were conducted and compared. The results show that, due to the consideration of wheel–rail adhesion model and traction control in the 3D model, it reports less energy consumption than the 1D model. The maximum difference in energy consumption rate between the 3D model and the 1D model was 12.5%. Due to the consideration of multiple wheel–rail contact points in the 3D model, it reports higher energy consumption than the 2D model. An 8.6% maximum difference in energy consumption rate between the 3D model and the 1D model was reported during curve negotiation.

Simulation Model of a Direct-Current Electric Locomotive with Commutator Traction Motors

A dc electric locomotive simulation model is considered that makes it possible to study transient and steady processes and may serve as a basis for the notion of a “digital locomotive” being implemented within the “Digital Railway” project. One of the most popular electric locomotives is selected, which is designed for pulling freight trains along long-distance railways electrified with direct current with a voltage of 3000 V. The electric locomotive model is based on a mathematical model of a collector traction engine. The model takes into account the nonlinearity of the main pole’s magnetic characteristic, as well as the effect of eddy currents in solid magnetic circuit sections on the magnetic flux variation. The model provides a mechanism for regulating motors in the course of investigations in accordance with operating conditions. The processes of resistor starting and voltage regulation by connection to resistors by means of transposition, as well as motor regulation by changing the magnetic flux, are taken into account. The possibility of using the developed model to study the traction substation–traction network–electric rolling stock system, which is determined by different operating modes of the traction network in the process of converting electrical energy into mechanical, is shown. Calculations of various locomotive operating modes in the event of failure in the contact network are carried out.

Prospective model of the hybrid shunting diesel locomotive

In the article, the studies are performed which confirm dependence of fuel consumption of the shunting locomotive on the train driving mode. Using a hybrid power plant in the shunting diesel locomotive is proposed, which can help significantly reduce fuel consumption, since shunting will mostly be powered by an alternative power source, and provide high environmental cleanliness of the locomotive both with the basic DC motor and the proposed new traction motor type – switched reluctance motor.

Restoration of Live steam locomotive model and Study on thermal efficiency

Restoration of Live steam locomotive model and Study on thermal efficiency

Parallel computing of wheel-rail contact

Railway wheel–rail contact simulations are the most important and time-consuming tasks when simulating the system dynamics of vehicles. Parallel computing is a good approach for improving the numerical computing speed. This paper reports the advances in parallel computing of the wheel–rail contact simulations. The proposed method uses OpenMP to parallelise the multiple contact points of all the wheel–rail interfaces of a locomotive model. The method has been implemented in the vehicle system dynamics simulation package GENSYS. Simulations were conducted using two numerical solvers (4th Runge-Kutta and HeunC) and a maximum of four computer cores. Simulation cases have shown exactly the same numerical results using serial computing and parallel computing, which prove the effectiveness of the parallel computing method. The HeunC solver achieved the same simulation results and is 3.5 times faster than the 4th Runge-Kutta method. Simulation results obtained from both numerical solvers show that parallel computing using 2, 3 and 4 computer cores can improve the simulation speeds by roughly 29, 39 and 41%, respectively. There is an apparent diminishing of the rate of improvement due to the increase of the communication resource overhead when more computer cores are used. Using up to four computer cores does not require revision of the GENSYS code, and simulations can be executed using personal computers.

Friction measurement and creep force modelling methodology for locomotive track damage studies

To understand the effect of locomotive dynamic behaviour on track damage, a great number of train operational parameters should be considered in the analysis. Two of the critical parameters are based on the introduction of friction-creep curves and in-train forces in the locomotive models. Due to the high costs of locomotive field-testing programs, this paper proposes a methodology that focuses on the introduction of friction measurements, performed with an experimental tribometer, and estimates in-train forces from locomotive/track multibody simulations. Two implementation cases, dry and lubricated friction conditions, are presented in this paper.

Locomotive wheel wear simulation in complex environment of wheel-rail interface

Affected by the traction/braking, creep control and wheel-rail interface environment, wheel wear of locomotives is more complicated than that of other rolling stock. A locomotive wheel wear simulation model is developed, which includes a 3D locomotive track coupling dynamics model, a rolling contact model for rail traction vehicles based on Kalker's simplified theory, a PI-based creep control model and a wheel material wear model based on frictional power. The advantages of the dynamics model built in this paper are evaluated through two typical simulation cases. The effects of traction/braking and creep control on wheel wear are comprehensively investigated. The results indicate that the natural vibration characteristics of the locomotive/track system can be well reflected, and their influence on wheel wear can be taken into account. Traction and braking have a great influence on wheel wear, which should be considered for locomotive wheel wear simulation. It is a better way to control creep by using a control mode with variable creep threshold value.

Locomotive Assignment Graph Model for Freight Traffic on Linear Section of Railway. The Problem of Finding a Maximal Independent Schedule Coverage

The paper is devoted to the formal statement and solution of a problem arising when assigning the locomotives for freight transportation realization in accordance with preset schedule. The goal is to determine whether the number of locomotives is sufficient at a specified initial allocation of them to perform all transport operations. The solution is presented in the form of an algorithm that builds the coverage of the schedule: the complete one, if it exists, or else the partial one being the maximal independent. The theorem is proved on one-to-one correspondence between the existence of the complete coverage and the sufficiency of the number of locomotives.

Assessment of battery-hybrid diesel-electric locomotive fuel savings and emission reduction potentials based on a realistic mountainous rail route

This paper presents a hypothetical conversion of a conventional heavy haul diesel-electric locomotive to its hybrid counterpart by incorporating a battery energy storage system. Starting from the basic parameters of a 1.6 MW diesel-electric locomotive currently found in the national railway company locomotive fleet, the quasi-static model of the locomotive is derived and validated. The conventional locomotive model is then converted to its hybrid counterpart by adding a battery energy storage system in parallel to the generator and equipping it with an adequate optimized energy management control strategy. The hybrid locomotive powertrain components are also appropriately re-sized in order to meet comparable traction force and power performance. Both the conventional and hybridized locomotive models are then used for the purpose of comparative analysis of main vehicle characteristics for the mountainous railway route driving scenario, which includes realistic slope and speed limitations. The obtained simulation results are used to gain insights about the possible advantages of the proposed conversion/drivetrain hybridization in terms of feasible reduction of fuel consumption and related CO2 emissions, while also considering additional hybridization costs and return-of-investment period.

A spatial dynamics model for heavy-haul electric locomotives considering the dynamic coupling effect of gear transmissions

A locomotive is usually powered by the electromagnetic torque which is transmitted from the traction motor to the wheelset by gear transmission. In order to investigate the dynamic coupling effects from the gear transmission subsystems on the entire locomotive dynamics system, a comprehensive spatial locomotive dynamics model that considers the dynamic coupling effect of the gear transmissions is developed based on the multibody dynamics theory. In this model, the moved Marker technique is employed to calculate the dynamic mesh force of the gear pairs through which more accurate time-varying gear mesh stiffness excitations could be imported, which is the core of this dynamic model. Then, the established locomotive dynamics model is validated by comparing with the experimental test results. Finally, the dynamic effects of the gear transmissions are revealed by comparing with the results from the traditional locomotive dynamics model without considering the dynamic excitations from the gear transmissions. The results indicate that the gear transmissions have negligible effects on the vibrations of the carbody and the bogie frame, and on the lateral vibrations of the motor and the wheelset. However, the gear transmissions have significant effects on the vertical and, in particular, the longitudinal vibrations of the motor and the wheelset. Thus, it is suggested that the dynamic effects of the gear transmissions are considered in the locomotive dynamics modeling, especially when the vibrations of the motors and the wheelsets are taken into account.

Proposal of Education Teaching Material Using a Steam Locomotive Model for Acquiring Manufacturing Technologies

In this study, a new education teaching material using a steam locomotive model to acquire technical skills of high accuracy and high-density assembly is proposed. The proposed teaching material is processed by hand finishing, a turning process, and welding. In this teaching material, the machining and assembling accuracy are evaluated by pressure values, which are required for running, as well as the travel distance of the steam locomotive model. Thus, this teaching material can be used for introductory education for acquiring manufacturing technologies, because the importance of the machining and assembling accuracy can be understood.

Sustainable development in Ho Chi Minh City: Current status and policy implication

HCMC has confirmed its role as an economic locomotive and effective development model for Vietnam and the Southern Key Economic Zone as well. In integrating actively into the world economy, HCMC’s biggest challenge in the coming decade is to secure a sustainable development. Examining sustainability of its economic development is also a challenge to researchers and policy-makers in Vietnam. Based on theories of development economics and data about HCMC economic development in 2011-2015, this research uses statistical description of data to estimate the development process in HCMC. We find that HCMC is yet not to secure a sustainable development but on the road to achieve this goal.

Effect of the drive system on locomotive dynamic characteristics using different dynamics models

Based on the theory of vehicle-track coupled dynamics and gear system dynamics, a locomotive-track coupled spatial dynamics model is established by considering the dynamic effects of the gear transmission system. The vibration responses of a locomotive’s major components are then simulated using three locomotive-track models, namely the proposed dynamics model with the gear transmissions, a locomotive-track coupled dynamics model that considers the traction motor, and the classical Zhai’s model. The locomotive dynamic responses of the three models are extracted and compared to reveal discrepancies between them so as to explore the dynamic effects of the power transmission system and clarify potential applications of these models. The results indicate that the dynamic effects of the gear transmissions have a negligible influence on the lateral vibrations of the locomotive components. However, they have obvious effects on the vertical and longitudinal vibrations of the wheelset and the traction motor. Another advantage of the locomotive dynamics model that considers the dynamic effects of the gear transmissions is that the dynamic performance of the drive system can be assessed in the vehicle vibration environment. This study provides theoretical references that can assist researchers in choosing the most appropriate locomotive dynamics model according to their specific research purpose.

Traction modelling in train dynamics

This paper presents five locomotive traction models for the purpose of train dynamics simulations, such as longitudinal train dynamics simulations. Model 1 is a look-up table model with a constant force limit to represent the adhesion limit without modelling the wheel–rail contact. Model 2 is improved from Model 1 by empirically simulating locomotive sanding systems, variable track conditions and traction force reduction due to curving. Model 3 and Model 4 have included modelling of the wheel–rail contact and traction control. Model 3 uses a two-dimensional locomotive model while Model 4 uses a three-dimensional locomotive. Model 5 is based on Model 2 and developed to simulate hybrid locomotives. Demonstrative simulations are presented for the case of longitudinal train dynamics. The results show that the consideration of locomotive sanding systems, variable track conditions and traction force reduction have evident implications on the simulated traction forces. There can be up to 30% difference in the simulated traction forces. Simulated traction forces by models that consider the wheel–rail contact are about 10–15% lower than those simulated by models without consideration of the wheel–rail contact. This is mainly due to the variable friction in the wheel–rail contact and conservative traction control schemes.

An Analytical Comparison of Locally-Connected Reconfigurable Neural Network Architectures Using a C. elegans Locomotive Model

The scale of modern neural networks is growing rapidly, with direct hardware implementations providing significant speed and energy improvements over their software counterparts. However, these hardware implementations frequently assume global connectivity between neurons and thus suffer from communication bottlenecks. Such issues are not found in biological neural networks. It should therefore be possible to develop new architectures to reduce the dependence on global communications by considering the connectivity of biological networks. This paper introduces two reconfigurable locally-connected architectures for implementing biologically inspired neural networks in real time. Both proposed architectures are validated using the segmented locomotive model of the C. elegans, performing a demonstration of forwards, backwards serpentine motion and coiling behaviours. Local connectivity is discovered to offer up to a 17.5× speed improvement over hybrid systems that use combinations of local and global infrastructure. Furthermore, the concept of locality of connections is considered in more detail, highlighting the importance of dimensionality when designing neuromorphic architectures. Convolutional Neural Networks are shown to map poorly to locally connected architectures despite their apparent local structure, and both the locality and dimensionality of new neural processing systems is demonstrated as a critical component for matching the function and efficiency seen in biological networks.

Deep Sparse Autoencoder for Feature Extraction and Diagnosis of Locomotive Adhesion Status

The model is difficult to establish because the principle of the locomotive adhesion process is complex. This paper presents a data-driven adhesion status fault diagnosis method based on deep learning theory. The adhesion coefficient and creep speed of a locomotive constitute the characteristic vector. The sparse autoencoder unsupervised learning network studies the input vector, and the single-layer network is superimposed to form a deep neural network. Finally, a small amount of labeled data is used to fine-tune training the entire deep neural network, and the locomotive adhesion state fault diagnosis model is established. Experimental results show that the proposed method can achieve a 99.3% locomotive adhesion state diagnosis accuracy and satisfy actual engineering monitoring requirements.

Dynamic Responses of 87-Type Railway Steel Beam for Rush-repair under Heavy Load Trains

87-type railway steel beam for rush-repair were established by the finite element analysis software ANSYS and five different spans of beams were taken into consideration in the research of dynamic responses. DF4 locomotive hauling C70 freight heavy load marshalling trains model was established by dynamics software UM, in which specific wheel and rail relationship was used to found a combined simulation vibration system. After modeling, process of train running through the bridge was simulated to study several indexes including mid-span vertical deflection, mid-span lateral amplitude, derailment coefficient, rate of wheel load reduction and lateral force of wheel. These indexes made it possible to find out the changing pattern and the conclusion of maximum recommended speed.

Study of Power Quality on the Interaction of Wind Farm and Electric Railway

Based on a real engineering project, by means of electro-magnetic transient simulation software EMTP-RV, a detailed simulation of the largest wind farm in Hubei Province (Xianghe Wind Farm) has been modeled, and an electric railway Huji traction station with locomotive load model is connected to the wind farm on the same 110kV bus. Multiple operating conditions such as the grid independently carrying load, wind farm connecting to the grid separately, electric railway load connecting to the grid separately, wind farm with different wind speed and different electric railway load simultaneously connecting to the same substation 110kV bus, are simulated and analyzed. A power quality calculation template was developed, and the corresponding power quality indexes were calculated. The simulation results show that the wind farm and electric railway load connected to the same bus will deteriorate the operating conditions of the grid PCC, and cause extremely voltage fluctuation and harmonic injection. Combining with field conditions, a number of improvement advises are put forward from the voltage fluctuation and the power oscillation phenomenon revealed by the simulation, such as: a reasonable scheduling of wind farm active reactive power output, adding harmonic compensation device at electric traction station, set up SVG reactive power compensation automatic control system at 110kV substation. After that, the improved PCC power quality will fulfill the national standards.

Locomotive Wheel Slip Control Method Based on an Unscented Kalman Filter

Railway traction vehicles transfer forces between wheels and rails through an adhesion coefficient. The adhesion coefficient value can decrease abruptly during the train run. Therefore, the wheels can simply gain high value of the wheels slip velocity. Thus, the vehicles are equipped with slip controllers for this case. During the past decades, many types of slip control strategies were developed, and the new methods are also developed today. Some perspective methods are based on an estimation of the adhesion coefficient or an adhesion force. However, correct operation of these methods is not guaranteed in all cases. Moreover, these methods have some weakness that can decrease their efficiency. Therefore, a novel method based on the adhesion condition estimation is presented in this paper. The adhesion condition is estimated by an unscented Kalman filter. When the method is connected to a controller, it is possible to eliminate the rising wheel slip velocity at its beginning and limit it to the appropriate value. The output of the method is directly used as an input of the controller without any additional calculation as it is used in traditional methods. The input signal does not need any additional filtration, and the method does not require information about the actual train velocity for its proper work. The verification of the method is done with the measured data that were measured on a freight train hauled by an electric locomotive. This paper also presents simulation results of the method with a controller based on the locomotive mathematical model.

Damage Degree Detection of Cracks in a Locomotive Gear Transmission System

The gear transmission system is a vital component of the locomotive bogie. During locomotive operation, the damage to the gear transmission system spreads rapidly and affects the locomotive’s operational safety. In this paper, a method is proposed to detect the degree of tooth root crack damage. First, a dynamic locomotive model with a gear transmission is built, and the vertical acceleration of the locomotive subsystem (car body, bogie frame, wheelset, and motor) vibrations is obtained under various degrees of tooth root crack damage on the gear transmission system. By comparing the characteristics of those signals, the subsystem that is more sensitive to the effect of the tooth root crack is found. The characteristic parameters of the sensitive subsystem are calculated, and a multidimensional characteristic parameter matrix is established. The multidimensional characteristic parameter matrix is optimized and reduced by principal component analysis (PCA). Using the Grey relational analysis method, the degree of tooth root crack damage is detected. The proposed method demonstrates the ability to recognize the degree of tooth root crack damage.