Preface to special issue on hybrid and hydrogen technologies for railway operations

These are exciting times for those working to develop and introduce zero emission technologies for the manufacture and operation of clean transport systems.The automotive industry in particular is taking rapid and significant steps to develop and implement clean and sustainable transport technologies.The railway industry is,relatively speaking,conservative in its progress in this field because it requires expensive long-term financial investment in rolling stock and railway infrastructure.However,the rail industry is also beginning to increase the pace of development.

Shunt-E 4.0—Autonomous Zero Emission Shunting Processes in Port and Hinterland Railway Operations

The port railway operation in Germany and Europe is not least due to its long history of technological and regulatory developments characterized by a high number of players and a lack of comprehensive planning and optimization of all relevant processes.Innovative technologies and business processes are therefore useful and needed to achieve key steps on the way to an overall optimization of rail transport within global supply chains.A substantial part of the European rail freight transport has its origin or its destination in an inland or sea port.Considering the railway system,ports play a more important role for urgently needed innovations than the pure interfaces between sea and land transport.Especially ports with their own railway system have an own responsibility in this matter.Insofar the goal of the Bremen Port Railway—which already now has a leading share of railway in modal split in Europe—is to exploit the opportunities offered by digitalization.Significant steps for this are the optimization and gradually automatization of rail operational processes on the last mile including modern and transparent IT systems and the designing of autonomous shunting processes.Together with research partners ISL(Institute of Shipping Economics and Logistics Bremen),BIBA(Bremen Institute for Production and Logistics)and IVE(Institute for Transport,Railway Construction and Operation in Brunswick)and in connection with associated business partners the project Rang-E has been applied for at the Ministry of Transport in the funding initiative IHATEC(Innovated HArbour TEChnologies)—and had won a grant to perform the proposed work.Basic thoughts are outlined in the following.

Experimental investigation on the invert stability of operating railway tunnels with different drainage systems using 3D printing technology

In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently,which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor to ensure the invert stability by regulating the external water pressure(EWP). By means of a threedimensional(3D) printing model, this paper experimentally investigates the deformation behavior of the invert for the tunnels with the traditional drainage system(TDS) widely used in China and its optimized drainage system(ODS) with bottom drainage function. Six test groups with a total of 110 test conditions were designed to consider the design factors and environmental factors in engineering practice,including layout of the drainage system, blockage of the drainage system and groundwater level fluctuation. It was found that there are significant differences in the water discharge, EWP and invert stability for the tunnels with the two drainage systems. Even with a dense arrangement of the external blind tubes, TDS was still difficult to eliminate the excessive EWP below the invert, which is the main cause for the invert instability. Blockage of drainage system further increased the invert uplift and aggravated the track irregularity, especially when the blockage degree is more than 50%. However, ODS can prevent these invert anomalies by reasonably controlling the EWP at tunnel bottom. Even when the groundwater level reached 60 m and the blind tubes were fully blocked, the invert stability can still be maintained and the railway track experienced a settlement of only 1.8 mm. Meanwhile, the on-site monitoring under several rainstorms further showed that the average EWP of the invert was controlled within 84 k Pa, while the maximum settlement of the track slab was only 0.92 mm, which also was in good agreement with the results of model test.

Research on Active Safety Methodologies for Intelligent Railway Systems

Safety is essential when building a strong transportation system.As a key development direction in the global railway system,the intelligent railway has safety at its core,making safety a top priority while pursuing the goals of efficiency,convenience,economy,and environmental friendliness.This paper describes the state of the art and proposes a system architecture for intelligent railway systems.It also focuses on the development of railway safety technology at home and abroad,and proposes the active safety method and technology system based on advanced theoretical methods such as the in-depth integration of cyber–physical systems(CPS),data-driven models,and intelligent computing.Finally,several typical applications are demonstrated to verify the advancement and feasibility of active safety technology in intelligent railway systems.

Energy Management of Networked Smart Railway Stations Considering Regenerative Braking, Energy Storage System, and Photovoltaic Units

The networking of microgrids has received significant attention in the form of a smart grid.In this paper,a set of smart railway stations,which is assumed as microgrids,is connected together.It has been tried to manage the energy exchanged between the networked microgrids to reduce received energy from the utility grid.Also,the operational costs of stations under various conditions decrease by applying the proposed method.The smart railway stations are studied in the presence of photovoltaic(PV)units,energy storage systems(ESSs),and regenerative braking strategies.Studying regenerative braking is one of the essential contributions.Moreover,the stochastic behaviors of the ESS’s initial state of energy and the uncertainty of PV power generation are taken into account through a scenario-based method.The networked microgrid scheme of railway stations(based on coordinated operation and scheduling)and independent operation of railway stations are studied.The proposed method is applied to realistic case studies,including three stations of Line 3 of Tehran Urban and Suburban Railway Operation Company(TUSROC).The rolling stock is simulated in the MATLAB environment.Thus,the coordinated operation of networked microgrids and independent operation of railway stations are optimized in the GAMS environment utilizing mixed-integer linear programming(MILP).

Development of rail technology for high speed railway in China

Purpose–The purpose of this paper is to summarize the status and characteristics of rail technology of high-speed railway in China,and point out the development direction of rail technology of high-speed railway.Design/methodology/approach–This study reviews the evolution of high-speed rail standards in China,comparing their chemical composition,mechanical attributes and geometric specifications with EN standards.It delves into the status of rail production technology,shifts in key performance indicators and the quality characteristics of rails.The analysis further examines the interplay between wheels and rails,the implementation of grinding technology and the techniques for inspecting rail service conditions.It encapsulates the salient features of rail operation and maintenance within the high-speed railway ecosystem.The paper concludes with an insightful prognosis of high-speed railway technology development in China.Findings–The rail standards of high-speed railway in China are scientific and advanced,highly operational and in line with international standards.The quality and performance of rail in China have reached the world’s advanced level.The 60N profile guarantees the operation quality of wheel–rail interaction effectively.The rail grinding technology system scientifically guarantees the long-term good service performance of the rail.The rail service state detection technology is scientific and efficient.The rail technology will take“more intelligent”and“higher speed”as the development direction to meet the future needs of high-speed railway in China.Originality/value–The development direction of rail technology for high-speed railway in China is defined,which will promote the continuous innovation and breakthrough of rail technology.

A train timetable rescheduling approach based on multi-train tracking optimization of high-speed railways

Purpose–This paper aims to propose a train timetable rescheduling(TTR)approach from the perspective of multi-train tracking optimization based on the mutual spatiotemporal information in the high-speed railway signaling system.Design/methodology/approach–Firstly,a single-train trajectory optimization(STTO)model is constructed based on train dynamics and operating conditions.The train kinematics parameters,including acceleration,speed and time at each position,are calculated to predict the arrival times in the train timetable.A STTO algorithm is developed to optimize a single-train time-efficient driving strategy.Then,a TTR approach based on multi-train tracking optimization(TTR-MTTO)is proposed with mutual information.The constraints of temporary speed restriction(TSR)and end of authority are decoupled to calculate the tracking trajectory of the backward tracking train.The multi-train trajectories at each position are optimized to generate a timeefficient train timetable.Findings–The numerical experiment is performed on the Beijing-Tianjin high-speed railway line and CR400AF.The STTO algorithm predicts the train’s planned arrival time to calculate the total train delay(TTD).As for the TSR scenario,the proposed TTR-MTTO can reduce TTD by 60.60%compared with the traditional TTR approach with dispatchers’experience.Moreover,TTR-MTTO can optimize a time-efficient train timetable to help dispatchers reschedule trains more reasonably.Originality/value–With the cooperative relationship and mutual information between train rescheduling and control,the proposed TTR-MTTO approach can automatically generate a time-efficient train timetable to reduce the total train delay and the work intensity of dispatchers.

Statistical delay distribution analysis on high-speed railway trains

The focus of this study is to explore the statis-tical distribution models of high-speed railway (HSR) train delays. Based on actual HSR operational data, the delay causes and their classification, delay frequency, number of affected trains, and space–time delay distributions are discussed. Eleven types of delay events are classified, and a detailed analysis of delay distribution for each classifica-tion is presented. Models of delay probability delay prob-ability distribution for each cause are proposed. Different distribution functions, including the lognormal, exponen-tial, gamma, uniform, logistic, and normal distribution, were selected to estimate and model delay patterns. The most appropriate distribution, which can approximate the delay duration corresponding to each cause, is derived. Subsequently, the Kolmogorov–Smirnov (K–S) test was used to test the goodness of fit of different train delay distribution models and the associated parameter values. The test results show that the distribution of the test data is consistent with that of the selected models. The fitting distribution models show the execution effect of the timetable and help in finding out the potential conflicts in real-time train operations.

EXPERIENCE THE RAILWAY FROM LHASA TO NYINGCHI

On June 25,2021,Tibet's first ectric railway,the Lhasa-Nyingchi Railway,was officially put into operation.This is the third railway to be opened in the Tibet Autonomous Region after the Qinghai-Tibet Railway and the Lhasa-Shigatse Railway.

Research progress on train operation safety in Xinjiang railway under wind environment

Railway lines in the Xinjiang wind area face severe wind disasters year-round,which seriously affects the safety and economy of the railway in China.Therefore,the wind characteristics and statistics of wind-induced accidents along the Xinjiang railway lines are presented and the basic research route for evaluating the train running safety under crosswinds and effective measures to improve the windproof performances of trains are proposed,which are meaningful to deal with wind-induced train accidents.Based on this research route,a series of numerical simulations are conducted to evaluate train safety and the corresponding measures are provided.The results show the following.The running safety of the train under crosswinds mainly depends on the aerodynamic loads acting on the train.The relationships between the safe speed limit and train type,the load weight,the embankment height,the road cutting depth,the railway line curve parameters,the yaw angle and other factors are obtained.The critical wind-vehicle speed relationship,as well as the engineering speed limit value under different running conditions,are determined.Large values of the aerodynamic and dynamic indices mainly appear in special locations,such as near earth-embankment-type windbreak walls,shallow cuttings and the transition sections between various types of windbreak walls.Measures such as increasing the height of the earth-embankment-type windbreak walls,adding wind barriers with reasonable heights in shallow cuttings and optimizing the design of different types of transition sections are proposed to significantly improve the safe speed limits of trains under crosswinds.

Research on emergency rescue technology and equipment for train operation accidents on a heavy-haul railway network

Bridges,tunnels,cuttings and high subgrade account for a relatively large proportion in China’s heavy-haul railway system,where 10000 t of unit trains and 20000 t of combined trains are in operation.When a train operation accident occurs,it can easily cause vehicle intrusions,slant-span lines,tipping and stacking.Based on the viewpoint of system engineering,rescue methods such as hoisting,lifting,pulling and overturning are integrated,according to the characteristics of heavy-haul transport and the construction practice of train accident rescue system.A scheme of technical research and equipment configuration relating to heavy-haul railway rescue in China is put forward based on the situation—embankment,bridge,tunnel(including cuttings),ramp and curve rescue,and so on—and three-dimensional finite-element modelling and calculation checks on the key components are carried out.

Natural disaster warning system for safe operation of a high-speed railway

In this paper,the least square support vector machine(LSSVM)is used to study the safety of a high-speed railway.According to the principle of LSSVM regression prediction,the parameters of the LSSVM are optimized to model the natural disaster early warning of safe operation of a high-speed railway,and the management measures and methods of high-speed railway safety operation under natural disasters are given.The relevant statistical data of China’s high-speed railway are used for training and verification.The experimental results show that the LSSVM can well reflect the nonlinear relationship between the accident rate and the influencing factors,with high simulation accuracy and strong generalization ability,and can effectively predict the natural disasters in the safe operation of a high-speed railway.Moreover,the early warning system can improve the ability of safety operation evaluation and early warning of high-speed railway under natural disasters,realize the development goals of high-speed railway(safety,speed,economic,low-carbon and environmental protection)and provide a theoretical basis and technical support for improving the safety of a high-speed railway.

Progress in high-speed train technology around the world

This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum operating speed. Emphasis is given to the newly developed high-speed train in China, CRH380. The theoretical foundations and future development of CRH380 are briefly discussed.

The Hum on Reforming China′s Railway Operating Cost Management System

This article introduces the historical evolution and the realities of china′s railway operating cost management system, then analyzes the various problems in it under current management system. And on the basis of the first two parts, the author gives proper design and advice, trying to be helpful to the great reform of the railway operating cost control system.

China's Communications Satellites and Their Benefits

Since 1984 China has launched 2 experimental and 4 operational communications satellites which have played an important role in the national e-conomic construction. TV transmission, TV education, long distance telephone and telegraph, data transfer in finance and railway traffic, etc.. This paper describes the status and features of these satellites in detail. Now, a new communications satellite with medium capacity , designated Dong-fanghong-3 (DFH-3), is under development and scheduled to be launched later 1993. It is also the first satellite that will be under commercial management in China.

A Hybrid Circuit Breaker Based on Current Commutation Approach for Multi-feeder DC Railway Substations

The paper presents an economic hybrid circuit breaker for limiting and interrupting the faults in DC railways substations. For fast fault current interruption, the hybrid breaker incorporates high speed mechanical contacts actuated by power semiconductor devices. Additionally, to avoid formation of electric arc, a commutation circuit is used to inject a counter current during fault interruption. In a real railway substation, each feeder is connected to the main DC bus through an expensive air magnetic DC circuit breaker and to an auxiliary DC bus through another expensive breaker. This leads to high cost especially in railway substation with multi feeders which are used to energize the vehicle transmission lines. In this paper, all DC breakers in DC railway substations are replaced by the suggested circuit breaker, which consists of a high speed mechanical contact with two semiconductor devices in each feeder and only one commutation circuit for injecting the counter current in all faulted feeders. The fault diagnosis is designed to detect the abnormal condition (current or voltage) in all feeders and direct the injected current from the commutation circuit to the faulted feeder only when the abnormal reaches a predetermine level. The suggested breaker is able to detect and interrupt any cascading of faults.

Reliability guarantee framework for the Sichuan-Tibet Railway

The Sichuan-Tibet Railway is facing extraordinary challenges in terms of construction,operation,and maintenance because of its extremely complicated natural environment and geological conditions.Consequently,countermeasures are necessary and urgent to ensure its safety and reliability in the whole life cycle.This study proposes a novel reliability framework to guarantee the ideal operation state of the Sichuan-Tibet Railway.Reliability application in many fields are summarized,including military equipment,rail locomotive,and railway engineering.Given the fact that the Sichuan-Tibet Railway is a complex giant system,Nine-Connotation was summarized(i.e.,safety,inherent reliability,testability,maintainability,supportability,environmental adaptability,predictability,resilience,and durability)under the goal of optimizing the operational efficiency.On the basis of the concept of the Nine-Connotation and the understanding of reliability transmission mechanism,the framework of reliability for the Sichuan-Tibet Railway was established,which can facilitate a comprehensive and real-time evaluation of all situations with a clear hierarchy.The proposed framework is composed of a resilience management system,an integrated technology system,and a dynamic reliability assessment system.The pathway for its application on railway construction was developed in this study.The proposed framework can assist in well-informed decisions for the construction,as well as the operation of the Sichuan-Tibet Railway.On the basis of a top-down design concept for the first time,this study emphasizes the railway's availability and validity to complete the assigned tasks as a whole,that is,operational efficiency.It also shows the reliability transmission and control mechanism of the railway's giant complex system,innovating and establishing the management principle of great safety and great reliability over the life cycle.

Train delay analysis and prediction based on big data fusion

Despite the fact that punctuality is an advantage of rail travel compared with other long-distance transport,train delays often occur.For this study,a three-month dataset of weather,train delay and train schedule records was collected and analysed in order to understand the patterns of train delays and to predict train delay time.We found that in severe weather train delays are determined mainly by the type of bad weather,while in ordinary weather the delays are determined mainly by the historical delay time and delay frequency of trains.Identifying the factors closely correlated with train delays,we developed a machine-learning model to predict the delay time of each train at each station.The prediction model is useful not only for passengers wishing to plan their journeys more reliably,but also for railway operators developing more efficient train schedules and more reasonable pricing plans.

Robust train speed trajectory optimization: A stochastic constrained shortest path approach

Train speed trajectory optimization is a significant issue in railway traffic systems, and it plays a key role in determining energy consumption and travel time of trains. Due to the complexity of real-world operational environments, a variety of factors can lead to the uncertainty in energy-consumption. To appropriately characterize the uncertainties and generate a robust speed trajectory, this study specifically proposes distance-speed networks over the inter-station and treats the uncertainty with respect to energy consumption as discrete samplebased random variables with correlation. The problem of interest is formulated as a stochastic constrained shortest path problem with travel time threshold constraints in which the expected total energy consumption is treated as the evaluation index. To generate an approximate optimal solution, a Lagrangian relaxation algorithm combined with dynamic programming algorithm is proposed to solve the optimal solutions. Numerical examples are implemented and analyzed to demonstrate the performance of proposed approaches.

京沪高铁舞动两大经济圈

6月30日15时,CRH380新一代高速列车G1次启动首秀之旅,从北京南站驶往上海虹桥站。世界最长、标准最高的高铁——京沪高速铁路通车运营。同一时刻,CRH380新一代高速列车G2次从上海虹桥站首发对开,中国环渤海和长江三角洲两个世界级经济圈结成"一日生活圈"。