High-speed Railway System Research Articles

Real-Time Hierarchical Neural Network Based Fault Detection and Isolation for High-Speed Railway System Under Hybrid AC/DC Grid

Real-Time Hierarchical Neural Network Based Fault Detection and Isolation for High-Speed Railway System Under Hybrid AC/DC Grid

Design of Cyber-Physical Systems Architecture for Prognostics and Health Management of High-speed Railway Transportation Systems

The high-speed railway (HSR) transportation system in China has been growing rapidly during the past decade. In 2016, the total length of HSR in China has reached to 22,000 kilometers, and there are over 2,000 pairs of high speed trains operating daily. With the advancement of design and manufacturing technologies, the reliability and construction costs have been improved significantly. However, there is still great need for reduction of their operation and maintenance costs. With such incentive, a pilot project has been launched to develop a prognostics and health management system for rolling stock to transform the maintenance paradigm from preventive to predictive maintenance. Considering the high task variety and big data environment in HSR real-time monitoring system, a cyberphysical system (CPS) architecture is proposed as the framework for its PHM system. This paper reviews the needs of predictive maintenance for the HSR system, and then present a concept design of the CPS-enabled smart operation and maintenance system.

Real-time optimization strategy for single-track high-speed train rescheduling with disturbance uncertainties: A scenario-based chance-constrained model predictive control approach

To improve the operational efficiency of high-speed railway system with disturbance uncertainties, a real-time optimization rescheduling strategy is designed based on the updated information for single-track high-speed railway system in this paper. Based on the characteristics of high-speed railway lines, a mixed-integer linear optimization model is constructed, where the decision variables involve the arrival times, departure times, arrival orders, departure orders and dwelling plans. Furthermore, to satisfy real-time requirements and to enhance the robustness of solutions, a scenario-based chance-constrained model predictive control (SC-MPC) algorithm is designed for solving the train rescheduling problem. Under the designed algorithm, the original linear model is converted to a non-linear mixed-integer model. To reduce the computational burden, the nonlinear model is converted to a linear mixed-integer model by a linearization method. The proposed strategy is compared with several typical benchmark strategies via a case study on the Beijing-Shanghai high-speed railway line. The simulation results show that the train delays can be effectively reduced by the proposed strategy and the rescheduling timetable has a good robustness.

Wear Problems of High-Speed Wheel/Rail Systems: Observations, Causes, and Countermeasures in China

Abstract Wear problems of wheel/rail systems occurring on the Chinese high-speed railway network in the last decade are summarized and explained together with the corresponding experience of treating them. Focus is placed on uneven wear because even wear is not an urgent issue due to its very low wear rate for the Chinese high-speed railway systems. Two typical problems of longitudinal uneven wear, namely, wheel polygonization and rail corrugation, are introduced in terms of their characteristics, consequences, causes and initiation mechanisms. Next, wheel hollow wear and flange/gauge side wear, as typical problems of lateral uneven wear, are similarly discussed. Validated countermeasures against all these problems are presented at the end of this paper together with further proposals under testing or consideration. This work is principally based on first-hand data collected from field observations, monitoring tests and dynamic measurements, but typical numerical approaches and results are also presented to help explain the observed phenomena.

Mitigating the vulnerability of an air-high-speed railway transportation network: From the perspective of predisruption response

Both the high-speed railway and air transportation network are the backbone of the interregional transport network and cover important cities in a country. Taking cities as nodes, a comprehensive interregional transportation network consisting of high-speed railways and civil aviation can be constructed. This network undertakes a huge passenger transportation task, so the failure of this network will cause serious economic losses and even casualties. In the Air-High-Speed Railway Transportation Network (A-HSRTN), the two transport modes can operate independently and can be alternatives. The analysis of the A-HSRTN helps planners to have a more comprehensive understanding of the vulnerability of the interregional passenger transport system. Mechanical failure, extreme weather and even man-made sabotage can threaten the operation of airports and stations. Optimizing the deployment of prevention resources can avoid or reduce the loss caused by those failure events in the A-HSRTN. This paper establishes a tri-level model to optimize the deployment of prevention resource from the perspective of predisruption response. This model takes the high-speed railway and air transportation system as an integrated transportation network to assign the limited prevention resources. The model aims to minimize the travel demand that cannot be satisfied in the worst failure scenario. Taking the A-HSRTN in mainland China as an example, this paper analyzes the model performance and the defense strategy obtained by this model. These case studies demonstrate that the method and model proposed in this paper can mitigate the vulnerability of the A-HSRTN.

How does spatial proximity to the high-speed railway system affect inter-city market segmentation in China: a spatial panel analysis

ABSTRACT The construction of the high-speed railway (HSR) system in China has improved cities’ interconnectedness. We contend that the improved interconnectedness will likely strengthen economic interaction among cities, particularly cross-border trade integration. Employing a spatial panel fixed effect error model with prefecture-level city data from 2008 to 2013, this paper evaluates how cities’ proximity to the HSR system affects urban market integration in China. We find that cities’ proximity to the HSR system exerts a positive influence on reducing market segmentation, ceteris paribus. This study for the first time assesses the impacts of cities’ proximity to HSR on inter-city market integration in China. The study will facilitate proactive regional policy decisions related to the future development of HSR and other critical infrastructure investment and development. Results obtained from the study could be of broader impact on policies of marketization reform and development for Eurasian countries.

OpenDSS를 이용한 국내 전기철도 급전계통 모델링

Commercial Electomagnetic Transient Programs show accurate transient results by solving differential equations with respect to the circuit, but are not suitable for fast, data-based analysis. The open source distribution simulator is an open program developed for planning and analysis of the distribution system, and provides a strong linkage function with external programs and fast processing speed. In this paper, a process of modeling through an open source distribution simulator was proposed by considering the double-track parallel feeding system applied to the domestic high-speed railway system as a representative. The proposed modeling method was verified by simulating the target system under the equal conditions with a transients program and comparing the results. Modeling and utilizing the railway system through flexible and simple text-based open software can contribute to future artificial intelligent-based analysis, or energy efficiency in terms of operational aspects.

A multi-criteria decision-making framework for site selection of distributed PV power stations along high-speed railway

The construction of distributed photovoltaic power stations (DPVPS) along high-speed railway can supply power for the traction power supply system (TPSS) of high-speed railway. The DPVPS site selection is a natural call from the practice with the consideration of full use of solar PV. This paper addresses a multi-criteria decision-making (MCDM) framework for DPVPS site selection along high-speed railway for the first time. In this framework, an evaluation criteria system is established. Considering the particularity of DPVPS site selection problem along high-speed railway, two new criteria namely power consumption capacity of high-speed railway TPSS and impact on high-speed railway TPSS are presented innovatively. In view of the strong grey correlations among criteria, the fuzzy grey relational projection (FGRP) method is applied to select the optimal site which is greatly suitable to deal with the grey correlations. A case in Hebei Province with sensitivity analysis also illustrates the robustness and effectiveness of the framework. The calculation results of the case indicate that the sub-criteria of impact on high-speed railway TPSS (C26) has the largest comprehensive weight, which is 0.129. Among the four candidate sites, G1 gets the highest final score of 0.653. This paper puts forward an effective tool for railway companies to choose the most suitable site to build DPVPS along high-speed railway, which has the certain practical significance.

Applicability analysis of high-speed railway system under the action of near-fault ground motion

Studying the applicability of existing bridge and track systems of high-speed railway in near-fault areas is crucial and urgent, because the current seismic design methods seldom consider the characteristics of the near-fault ground motion. By comprehensively considering the uncertainties in ground motion and structural parameters, a large-sample analysis method for near-faults area was proposed. In addition, an integrated finite element model for beam bridge-track system of high-speed railway was used to calculate the seismic response of the structure under the action of near-fault ground motion. The over-limit state and applicability of seismic response of key components and systems were predicted and evaluated. The analysis results indicate that the statistical characteristics of structural seismic response and over-limit state tend to be stable with increasing number of samples. Under the near-fault ground motion: (i) the piers of high-speed railway are hard to yield (ii) bearings are damaged severely, and (iii) the piers have insufficient shear capacity and the characteristics of structural seismic damage are not in accordance with the concept of ductility design. The sliding layer of the track structure is severely damaged by the transverse and longitudinal ground motions, while the CA mortar layer and fastener are mainly damaged by the transverse ground motion. The applicability of bearings, the anti-shearing behavior of piers, and the inter-layer structure of tracks make it difficult to achieve the goal of the near-fault fortification against ground motion.

A partial compensation scheme for MMC-based railway cophase power supply

Abstract This paper presents a partial compensation scheme for V/v transformer cophase traction power supply in high-speed railway systems. The scheme compensates variable traction load current, and controls the current phase at the secondary side of the V/v transformer for power factor correction and negative sequence current reduction. To achieve this, the grid side current phase angles are optimized while satisfying the grid code on the power factor and voltage unbalance limits. The optimized phase angles are then used to design control references under varying load conditions. The compensation control action is updated regularly based on real-time measurements of the traction load, and the required currents are controlled by a 25-level single-phase back-to-back MMC power conditioner to achieve the compensation target. Static and dynamic load compensation performances are verified based on the simulation studies.

Network analysis and spatial agglomeration of China’s high-speed rail: A dual network approach* *Project supported by the National Key Research and Development Program of China (Grant No. 2019YFF0301400) and the National Natural Science Foundation of China (Grant Nos. 61671031, 61722102, 41722103, and 61961146005).

China has the largest high-speed railway (HSR) system in the world, and it has gradually reshaped the urban network. The HSR system can be represented as different types of networks in terms of the nodes and various relationships (i.e., linkages) between them. In this paper, we first introduce a general dual network model, including a physical network (PN) and a logical network (LN) to provide a comparative analysis for China’s high-speed rail network via complex network theory. The PN represents a layout of stations and rail tracks, and forms the basis for operating all trains. The LN is a network composed of the origin and destination stations of each high-speed train and the train flows between them. China’s high-speed railway (CHSR) has different topological structures and link strengths for PN in comparison with the LN. In the study, the community detection is used to analyze China’s high-speed rail networks and several communities are found to be similar to the layout of planned urban agglomerations in China. Furthermore, the hierarchies of urban agglomerations are different from each other according to the strength of inter-regional interaction and intra-regional interaction, which are respectively related to location and spatial development strategies. Moreover, a case study of the Yangtze River Delta shows that the hub stations have different resource divisions and are major contributors to the gap between train departure and arrival flows.

Joint Power Allocation Scheme for Distributed Secure Spatial Modulation in High-Speed Railway

In this article, a distributed secure spatial modulation (DSSM) is proposed to improve the secrecy performance of transmission system in high-speed railway (HSR) scenario. N-remote antenna units are connected with central processing unit to build a cooperative DSSM system. Considering the influences of correlated shadow fading, spatial-temporal correlated fading and Doppler shift, the expressions of secrecy capacity (SC) and bit error rate (BER) are derived. Based on the design of artificial noise, two power allocation algorithms are jointly proposed as security schemes in HSR scenario. At first, a joint optimal secrecy capacity algorithm (JOSCA) is proposed to maximize SC. Another Lagrange constraint extreme algorithm (LCEA) is proposed to maximize inhibition of eavesdropper's BER performance. The numerical results show that compared to conventional spatial modulation, the proposed DSSM with JOSCA brings higher SC and keeps a high value of cooperative SC as the advance of train. Moreover, the proposed LCEA brings better BER performance of legitimate receiver while greatly limiting that of eavesdropper. In terms of the tradeoff between SC and BER, the DSSM gets better balance at the viaduct of high-speed railway scenario.

Seismic response of high-speed railway bridge-track system considering unequal-height pier configurations

The unequal-height pier configurations commonly exist in bridge engineering for the adaptation of the varying topography. However, this makes the stiffness of unequal-height piers fluctuating due to the pier's height difference. As piers are the main seismic-resisting components under earthquakes, the irregular stiffness distribution induced by unequal-height pier configurations are unfavorable to the seismic performance of bridge structures. Especially, the high-speed railway (HSR) bridges, which are designed to satisfy strict requirements of structural stability, integrity and smoothness allowing for high velocity, high comfort, high security, are more likely to be adversely affected by the unequal-height pier configuration. Additionally, previous study showed that the track structure that built on the HSR bridge girders is prone to be seismically damaged. Based on this, this paper studies the influence of the unequal-height pier configurations on the seismic displacement responses of HSR bridge-track system, and investigates the damage mechanism. The seismic performance of HSR bridges with different pier configurations are also evaluated from the perspective of probability. Piers with 8 m, 16 m and 24 m are utilized to constitute the symmetric and asymmetric layouts of equal-height and unequal-height pier configurations. Six numerical models of bridge-track system (BTS) are established based on the test data and previous researches. The analysis on seismic responses of six BTS models shows that seismic displacement responses of moveable bearings, sliding layer and shear alveolar rises with the increase of adjacent pier's height difference; It is found that unequal-height piers are more likely to produce large nonuniform displacement responses, which further causes larger displacement responses of components above piers. The moveable bearings are the least fragile in the equal-height pier configuration. However, the sliding layer and the shear alveolar are the most vulnerable with considerable displacement responses in the layout of 8 m and 24 m piers, and become less fragile in the unequal-height pier configuration of 8 m and 16 m piers. In terms of structural safety, the equal-height pier configuration has the least adverse influence on the seismic performance of HSR bridges.

High-Speed Maglev Train Battery Design Considering of the Position of Assist Stop Areas

With the increase of the operation speed in the high-speed maglev railway system, the distance between the assist stop areas can be increased. To ensure the safe operation between the two assist stop areas, the capacity of the onboard storage battery in maglev trains shall be redesigned. This paper derives the distance between the assist stop areas in different operation speed, which generate the speed curves for calculating the minimum battery capacity required for operation. We analysed the capacity requirements of the maglev battery at the different commercial operation and maintenance operation speed, as well as the impact of the battery capacity to the location design of the assist stop area, which can provide the guidance to the design of the onboard battery capacity in high-speed maglev train.

8 th Symposium on Mechanics of Slender Structures 2019 (MoSS2019)

8 th Symposium on Mechanics of Slender Structures 2019 (MoSS2019)

Optimal planning of distributed photovoltaic generation for the traction power supply system of high-speed railway

The ever-increasing electricity price and energy consumption in high-speed railway industry push railway companies to seek a promising way to realize their sustainable developments. Making full use of the solar resource along with high-speed railways can be a potential solution to cut the electricity bill, bring more profit to railway companies and realize the decarbonization of high-speed railway industry. This paper studies the optimal planning of distributed photovoltaic generation (DPVG) and energy storage system (ESS) for the traction power supply system (TPSS) of high-speed railway. A quantitative method is proposed to study the time and space characteristics of photovoltaic generation and electricity demand of high-speed trains. An integrated cost-benefit analysis framework is developed to evaluate the effect of DPVG and ESS on the economy of TPSS. To derive the optimal planning scheme and energy management strategy of DPVG and ESS, a mathematical programming model with the objective of minimizing the total cost is proposed to seek the most economical solution. A hybrid global optimal solution approach is developed to solve the model. A real-world case of Beijing-Baoding high-speed railway in China is used to illustrate the capability and characteristics of the proposed model. The computational results show that DPVG is able to supply 32.5% electricity demand of high-speed trains. The integration of DPVG and ESS can help railway company save 4.2 million CNY each year in Beijing-Baoding high-speed railway. This paper demonstrates the potential and applicability of DPVG and ESS in high-speed railway industry.

LiDAR Point Cloud Recognition of Overhead Catenary System with Deep Learning.

High-speed railways have been one of the most popular means of transportation all over the world. As an important part of the high-speed railway power supply system, the overhead catenary system (OCS) directly influences the stable operation of the railway, so regular inspection and maintenance are essential. Now manual inspection is too inefficient and high-cost to fit the requirements for high-speed railway operation, and automatic inspection becomes a trend. The 3D information in the point cloud is useful for geometric parameter measurement in the catenary inspection. Thus it is significant to recognize the components of OCS from the point cloud data collected by the inspection equipment, which promotes the automation of parameter measurement. In this paper, we present a novel method based on deep learning to recognize point clouds of OCS components. The method identifies the context of each single frame point cloud by a convolutional neural network (CNN) and combines some single frame data based on classification results, then inputs them into a segmentation network to identify OCS components. To verify the method, we build a point cloud dataset of OCS components that contains eight categories. The experimental results demonstrate that the proposed method can detect OCS components with high accuracy. Our work can be applied to the real OCS components detection and has great practical significance for OCS automatic inspection.

Wideband Modeling of Power SiC mosfet Module and Conducted EMI Prediction of MVDC Railway Electrification System

The SiC mosfet in the medium-voltage direct-current (MVdc) transportation electrification system features faster switching performance, while simultaneously binging more significant electromagnetic interference (EMI) issues within the rolling stocks, substations, and radiated disturbance into space along the catenaries and tracks. Due to the necessity to involve both the transient characteristics of power semiconductor devices and the stray parameters of all the equipment in the analysis of EMI, it is considerably challenging to perform wideband device-level simulation on traditional commercial software for such a complex system with numerous trains and stations. A computationally efficient method for wideband modeling and simulation of the MVdc high-speed railway system for the assessment of conducted EMI during the project design stage is proposed in this article. Physical characteristics of the semiconductor devices, parasitic parameters of the mosfet package, and converter topology are all taken into consideration to provide not only accurate system-level performance of the system but also an insight into high-frequency characteristics under different operation conditions. The calculation burden is alleviated by a hierarchical circuit partitioning architecture based on the frequency-dependent time-domain transmission line model and the Norton equivalent parameter extraction of each mosfet module to split the whole system into several smaller subcircuits in terms of matrix size, and a fully parallel implementation of the MVdc system is carried out on the graphics processor. The developed program is used to study the case of Jing–Zhang high-speed railway system topology, which is compatible to be modified to the MVdc project. Simulation results show that it is essential to estimate the EMI level comprehensively considering the alternative of speed and dc voltage.

Analysis of the Vibration Characteristics of Ballastless Track on Bridges Using an Energy Method

Although the high-speed railway (HSR) system has been widely agreed to be a sustainable and convenient means of transportation, the vibration induced has already been deemed an urgent environmental problem. For the sake of investigating the vibration characteristics of the ballastless track on bridges in the HSR system from the point of view of energy, a numerical model of the vehicle–track–bridge coupled system is developed herein and the energy method based on power flow theory is employed. In addition, a corresponding evaluation method of the power flow theory is developed to evaluate the vibration characteristics of the track–bridge system. The conclusions indicate that (1) the vibration energy gradually attenuates from top to bottom of the track–bridge system in its transfer process. Moreover, the attenuation effects are mainly the result of the elasticity and damping effects of the fasteners and the slab mat layer. (2) With increasing slab mat layer stiffness, the vibration energy of the rail slightly decreases; on the contrary, that of the slab track and the bridge obviously increases. (3) With increasing fastener stiffness, the vibration energy of the entire track–bridge system increases. (4) With increasing running speed, the vibration energy of the entire track–bridge system rises obviously. The results reveal that the reasonable stiffness levels of the fasteners and the slab mat layer are 40 to 60 kN/mm and 40 to 60 MPa/m, respectively, under the investigated condition in this work. This work also presents a novel way to study the vibration characteristics of the ballastless track on bridges of HSRs in terms of energy.

Experiment, Optimization, and Design of Electromagnetic Track Brake for High-Speed Railways System

To enhance braking force and control convenience of high-speed railway systems, this paper proposes a new electromagnetic track brake, and the corresponding design, optimization, and experimental test are implemented. The proposed track brake is longitudinal-axis magnetic circuits excited by multiple coils electromagnets, and the pole shoes are extending outward. A preliminary design of an electromagnetic track brake is developed, including iron core height, iron core width, iron core gap, excitation ampere-turn, coil arrangement form, coil thickness, and preliminary height of single-layer coil. The electromagnet number and pole shoe gap are optimized through three-dimensional electromagnetic simulation comparisons. The final design of the electromagnetic track brake is determined, including iron core length, copper wire diameter, coil turn, and final height of single-layer coil. Experimental verification of electromagnetic attractive force is performed through prototype tests, and the newly developed electromagnetic track brake can enhance electromagnetic braking deceleration by 39%.