Automatic Train Control Research Articles

Prospects of autonomous railway transport development

The implementation of unmanned train control systems offers a number of advantages, such as increasing the capacity of railway lines and traffi c volumes, reducing the ‘human factor’, as well as reducing operating costs. The paper considers the challenges arising from the use of automatic train control systems, and presents the prospects for the implementation of automatic technologies in railway transport for various railway systems. The social and economic aspects of changing professional activities in railway transport are described. Grades of automation applicable to surface urban railwaytransport are presented. The issues of proving the functional safety of machine vision systems as part of the train traffic control system and determining their level of safety completeness are discussed. Examples of railway transport automation in Russia and other countries are given. Basic scenarios of automatic control system operation describing normal and abnormal situations are formulated. In conclusion, the levels of technological readiness of the reviewed solutions in the fi eld of train traffic automation are defi ned. The tasks faced by railway companies in implementing these technologies are outlined, and possible ways of overcoming obstacles to the introduction of automatic systems are proposed, taking into account the current political situation.

Automated train driving: risk analysis validation

Aim. The paper is dedicated to describing the validation of risk analysis as part of an automated train control research project. Methods. Validation was performed using several different methods. The obtained results were compared with those obtained from other sources. Additionally, an independent risk analysis was performed using the alternative MEM (minimum endogenous mortality) method. Results. The validation showed that the project’s findings are reliable. Safety Integrity Levels (SIL) 1 or 2 were confirmed for train driver substitution systems. Conclusions. It was shown that various methods should be used for the purpose of risk analysis validation. It must be taken into account that comparable, but not identical results will be obtained.

Прогноз случайных процессов, при наличии единичных возмущений в интеллектуальных транспортных системах

Forecasting random perturbations allows improving the control quality in intelligent transport systems and ensuring the efficient operation of diagnostic systems. Several works are known where extrapolator models based on Chebyshev polynomials orthogonal on equidistant points are presented. These models use a predictive polynomial whose coefficients are computed using the least squares criterion. Additionally, an analysis of forecast errors for random stationary input signals has been conducted. At the same time, in the case of non-stationary input signals, singular perturbations may occur, the influence of which on the extrapolator leads to significant forecast errors.
 This article presents an example of the occurrence of additive perturbations that arise in automatic train control systems. An analytical expression has been derived, and calculations of forecast error magnitudes in the presence of singular perturbations have been conducted. The analysis of the calculation results allows determining the influence of extrapolator parameters on the forecast error magnitude, highlighting the necessity of detecting singular perturbations, and excluding their influence on the forecast error magnitude.
 The article discusses an algorithm for detecting singular perturbations and their exclusion during the forecasting process. The conclusion is drawn about the effectiveness of using extrapolators for random perturbations with the exclusion of singular perturbations in intelligent systems for automatic train control in subway transportation.

An adaptive safety control approach for virtual coupling system with model parametric uncertainties

Virtual coupling attracts extensive attention from the railway communities due to its promising capacity increase and flexibility improvement. Accurate control that guarantees system safety and performance remains a problem that needs to be further studied. This paper investigates the virtual coupling train system (VCTS) safety control problem with model parameter uncertainties using an adaptive nonlinear control strategy based on urban rail transit systems. A safe automatic train control model is introduced, and a novel control framework consisting of two levels is designed to give an overall virtual coupling train control architecture. For the leading train, we deploy an automatic train control system based on dynamic programming. Then, considering parameter uncertainties, we design an adaptive nonlinear controller that ensures safety and control efficiency for the following trains. The proposed control strategy can ensure that a virtually coupled train set tracks the given speed curve and keeps inner distance while guaranteeing the string stability and safety of the platoon, considering parameter uncertainties. The simulation results show that the proposed approach leads to great performance improvement in virtual coupling train operations.

Research on Tracking Control of Urban Rail Trains Based on Improved Disturbance Observer

Urban rail transit trains operate in a complex and changing environment susceptible to uncertainties such as unknown disturbances or actuator faults. In order to ensure that the automatic train control (ATC) system can operate safely and control accurately even when the train is affected by uncertainties, the train is first subjected to force analysis, and a multiple point-mass model for the urban rail trains (URTs) is established. Secondly, an improved disturbance observer is proposed to estimate and attenuate the unknown disturbance online. The stability of the URTs system under the improved disturbance observer-based control (IDOBC) is demonstrated based on the linear matrix inequality and Lyapunov theorem. Finally, the Simulink platform is used to verify the target curves obtained after data optimization of the certain Nanchang Metro line for case verification. Compared to the traditional disturbance observer-based control (TDOBC) method, the train tracking error converges to near the zero region faster after being subjected to an external disturbance, and the mean absolute error (MAE) metric is smaller throughout the whole operation. The control strategy proposed in this paper has a more desirable control effect and can ensure the safer and more stable operation of the URTs.

Next-Generation Connectivity in A Heterogenous Railway World

Global System for Mobile communication - Railway (GSM-R) is widely used for operational communications between train and signaler. However, there is a need to define a successor that addresses: obsolescence, radio spectrum demand and the enabling of a range of emerging digital applications such as radio-based signaling and Automatic Train Control (ATC). Therefore, the International Union of Railways (UIC) started the initiative to develop the Future Railway Mobile Communication System (FRMCS). This article describes an Adaptable Communication System (ACS) that is being developed jointly by industry and railway operators as a possible successor covering all types of railways and all aspects of the FRMCS. A pragmatic approach is suggested that considers diverse railway settings and makes use of various radio access technologies. Countries, geographical regions and infrastructure managers differ concerning available radio technologies, but use of a suitable ACS could pave the way towards innovation in the railway sector. For this adaptive concept we discuss several network models and enhancements including satellite communications (SatCom), Software-Defined Networking (SDN) integration and antenna systems that support multiple bearers in one. For SatCom a software defined radio (SDR) prototype using random access is presented that is able to fulfill the requirements of ETCS. We found that SDN can be used for dynamically changing the access technology for critical and non-critical railway use cases. Furthermore, we present an antenna prototype that can be used for 5G, GSM, WLAN and LTE in parallel which saves limited mounting surface on the train.

Augmented digital twin for railway systems

The information that automated train control (ATO) systems use to improve safety and reduce power usage is limited by on-board and wayside monitoring applications and computing power. This paper presents an augmented digital twin for railway applications that enables real-time consideration of derailment risk in train operations. The augmented digital twin implements a surrogate model with the results of a massive multibody dynamics numerical program and machine learning models to predict the instantaneous wagon derailment risk. A case study for a heavy haul iron ore wagon with three-piece bogies was conducted to test the augmented digital twin. A multibody simulation numerical program comprising 2100 simulation cases was completed. The surrogate model was developed using linear, polynomial, decision tree and ensemble forest regression models on the results of the numerical program. A longitudinal train simulator was used to calculate the speed and lateral coupler force throughout a train trip. The surrogate model effectively predicted the derailment index for empty and loaded conditions accounting for lateral coupler forces, vehicle speeds and curve radius. The proposed augmented digital twin can be further developed to accomplish other train operational benefits such as the reduction of rail damage.

Haberleşme Tabanlı Tren Kontrolünün (CBTC) Otomatik Tren Korumasına (ATP) İlişkin Dağıtılmış-Hiyerarşik Kontrol Yaklaşımı

Kentleşme ile birlikte metropollerde yaşayan insan sayısı artmaktadır, nüfus artışına paralel olarak şehir içi ulaşımda çok önemli bir yer tutan raylı ulaşım sistemlerine olan talep, kalabalık şehirlerde her geçen gün daha da artmaktadır.Artan talebe paralel olarak raylarda artacak trafik yoğunluğu, sinyalizasyon sistemlerini güvenlik, kapasite ve rayların verimine etkisi açısından oldukça önemli kılmaktadır. Günümüzde birçok raylı ulaşım sistemlerinde sinyalizasyon sistemi olarak Haberleşme Tabanlı Tren Kontrol (CBTC) tercih edilmektedir. CBTC, Otomatik Tren Koruması (ATP), Otomatik Tren Denetimi (ATS) ve Otomatik Tren İşletmesi (ATO) gibi bazı alt sistemlerden meydana gelmektedir. Alt sistemlerin kendine özgü tanımlanan bazı görevleri bulunmaktadır. Bu görevleri yerine getirirken, alt sistemlerden artan gereksinimlerden etkilenmeden, istenen emniyet fonksiyonlarını en üst düzeyde güvenle uygulaması beklenmektedir. Ancak, bu sistemlerin genel tasarımının, ihtiyaç duyulan yeni gereksinimlere göre değiştirilmesi gerekebilir. Bu bağlamda çeşitli standartların sağlarken, alt sistemlerin kontrol edilmesi ve modellenmeleri büyük önem taşımaktadır. Bu çalışmada, CBTC’nin alt sistemi ATP, ayrık olay sistemi yaklaşımıyla sonlu durum otomatları ile modellenmiştir ve alt sistemlere ait denetimsel gözetleyicilerin tasarımı yapılarak, kontrol edilebilirlik ve kilitlenmesiz kontrol koşullarını karşıladığı gösterilerek, elde edilen sonuçlar yekpare yaklaşım modeli ile karşılaştırılmıştır.

Real Time Control System for Metro Railways Using PLC & SCADA

This paper proposes to adopt SCADA and PLC technology for the improvement of the performance of real time signaling & train control systems in metro railways. The main concern of this paper is to minimize the failure in automated metro railways system operator and integrate the information coming from Operational Control Centre (OCC), traction SCADA system, traction power control, and power supply system. This work presents a simulated prototype of an automated metro train system operator that uses PLC and SCADA for the real time monitoring and control of the metro railway systems. Here, SCADA is used for the visualization of an automated process operation and then the whole operation is regulated with the help of PLC. The PLC used in this process is OMRON (NX1P2-9024DT1) and OMRON’s Sysmac studio programming software is used for developing the ladder logic of PLC. The metro railways system has deployed infrastructure based on SCADA from the power supply system, and each station’s traction power control is connected to the OCC remotely which commands all of the stations and has the highest command priority. An alarm is triggered in the event of an emergency or system congestion. This proposed system overcomes the drawbacks of the current centralized automatic train control (CATC) system. This system provides prominent benefits like augmenting services which may enhance a network’s full load capacity and network flexibility, which help in easy modification in the existing program at any time.

A Comprehensive Resilient Control Strategy for CBTC Systems Through Train-to-Train Communications Under Malicious Attacks

In recent years, intelligent transportation systems and automatic train control technologies have been developed rapidly. The communication-based train control (CBTC) system through train-to-train communications is very important in the intelligent transportation system and it uses wireless communication links to transmit the train control commands. However, the CBTC system is sensitive to information security attacks. Therefore, a comprehensive resilient control strategy is proposed for the CBTC system under Denial of Service (DoS) attacks. As a cyber physical system, the CBTC system includes two layers. In the communication layer, a strongly robust train-to-train communication topology is proposed which adopts a bidirectional communication strategy and a three times communication protocol to achieve the goal of resisting multi-channel DoS attacks. In the physical layer, an observer-based distributed intrusion detection method is firstly proposed to detect the attack. Further, a resilient control method based on a distributed state observer of the leader train is proposed to avoid triggering the train safety protection mechanism frequently. Finally, simulation results prove that the proposed comprehensive resilient control algorithm is effective in the CBTC system.

Verified Train Controllers for the Federal Railroad Administration Train Kinematics Model: Balancing Competing Brake and Track Forces

Automated train control improves railroad operation by safeguarding the motion of trains while increasing efficiency by enabling motion within a safe envelope. Train controllers decide when to slow trains down to avoid collisions with other trains on the track, stay inside movement authorities, and navigate slopes, curves, and tunnels safely. These systems must base their decisions on detailed motion models to guarantee the absence of overshoot of the movement authority (safety) and limit undershoot (efficiency). This article is the first to formally verify the safety of the Federal Railroad Administration freight train kinematics model with all its relevant forces and parameters, including track slope and curvature, air brake propagation, and resistive forces as computed by the Davis equation. Due to the significant competing influence of these parameters on train stopping distances, even designing train controllers is a nontrivial control challenge, which we solve using formal verification. For increased generality at reduced verification effort, we verify symbolic mathematical generalizations of the train control models and subsequently apply efficient uniform substitutions to obtain verification results for physical train control models.

Energy-efficient automatic train operation for high-speed railways: Considering discrete notches and neutral sections

The energy-efficient driving of automatic train operation (ATO) system in high-speed railway systems has attracted more and more attention. Different from the energy-efficient automatic train control problem for metro trains, the traction/braking forces given by high-speed ATO systems are currently not continuous but discrete values corresponding to traction/braking notches due to the limited communication interface between ATO systems and rolling stocks. In addition, since high-speed trains are powered by single-phase alternating current, there is no power supply for train traction in neutral sections, which is introduced to separate two catenaries powered by currents with different phases. In this paper, we propose a discrete-space based mathematical formulation for the energy-efficient automatic train control problem for high-speed trains, where binary variables are introduced to indicate the traction/braking notch selections and to indicate whether a discrete space interval is a neutral section or not. The mathematical formulation is then transformed into a mixed integer linear programming (MILP) model, which can be solved by existing solvers. However, due to the discretization of the space the discrete traction/braking notches, the resulting MILP problem could be infeasible and the optimal driving strategy cannot be obtained. Hence, we present a novel relaxation method, i.e., the final braking notch relaxation method, to relax a few constraints in the final braking phase and to generate a feasible speed profile. Comprehensive experiments are investigated based on Beijing–Harbin high-speed railway line, where the energy consumption of the speed profiles with discrete (i.e., notch-based) traction/braking forces is slightly higher than that with continuous traction/braking forces. Moreover, the impacts of the neutral section locations and the effects of different numbers of traction/braking notches are deeply analyzed.

Communication-Based Train Control with Dynamic Headway Based on Trajectory Prediction

Rail transit plays a significant role in the operation of an efficient and effective urban public transportation system. Safety and capacity are some of the most crucial objectives in railway operations. The communication-based train control (CBTC) system is a continuous and automatic train control system that realizes constant and high-capacity train ground two-way communication. In this study, a dynamic headway model of the ‘softwall’ moving-block approach is proposed for CBTC to increase the track capacity and improve dispatching efficiency based on the train trajectory prediction. For this precise trajectory prediction task, we introduce a hybrid trajectory prediction model to combine Long Short-term memory (LSTM) and Kalman Filter (KF) to extract the train’s local data features and learn the long-term dependencies, respectively. Then we present a dynamic headway model to maximize the train headway and reduce the track distance. The leading trains’ information is used to construct the iterative learning control strategy, and the predicted trajectory is input into the algorithm of the headway model. We use a simulation model of the rail network in Chengdu to demonstrate the effectiveness of our proposed approach. The results show the Mean Absolute Error (MAE) of the predicted trajectory retreated to 93.97 cm and reductions in operation headway of at least 64.33% under the dynamic headway model versus the traditional moving-block model.

Dynamic speed trajectory generation and tracking control for autonomous driving of intelligent high-speed trains combining with deep learning and backstepping control methods

The development of autonomous transportation systems has received increasing attention over the last decades. Different from existing automatic train control systems, the decision-making capability in the autonomous driving system enables a train to adapt to the complicated and dynamic circumstances. This paper in particular focuses on the decision-making problem for the autonomous driving of intelligent high-speed trains, and proposes a novel decision-making framework by combining the deep learning and backstepping control methods. By exploiting the deep learning methods, a speed trajectory generator is trained with the actual driving data, and dynamically calculates the reference speed trajectory according to the real-time driving condition. Then, a backstepping controller is designed to track the reference speed trajectory such that the separation, cohesion and alignment requirements for the autonomous driving of high-speed trains are achieved. Simulation experiments are implemented to illustrate the effectiveness of our methods.

Constrained Spatial Adaptive Iterative Learning Control for Trajectory Tracking of High Speed Train

This paper proposes a constrain spatial adaptive iterative learning controller (CSAILC) for the displacement-speed trajectory tracking of automatic train control system with unknown parametric/nonparametric uncertainties and speed constraints. First, the nonlinear dynamic model of train operation is transformed from temporal domain into spatial domain utilizing a spatial state differentiator. Besides, the displacement-related parametric/nonparametric uncertainties are updated in the iteration axis. Furthermore, a barrier function is involved to satisfy the speed constraint, and the corresponding convergence analysis of the proposed CSAILC for automatic train control (ATC) is derived based on the spatial composite energy function. In addition, numerical simulations of train tracking control are carried out, and simulation results indicate that the proposed CSAILC achieves good effectiveness in a high-speed train (HST) control system.

INFORMATION ANALYSIS OF THE EXPERT SYSTEM OF AUTOMATIC TRAIN CONTROL

The expert system for automatic control of train traffic belongs to the class of information systems of automation and tele mechanics. The model, which reflects the informational links between the main goal and the characteristics of the automatic train control system, is informational. It can be used to conduct a qualitative analysis and synthesis of the system.

РЕШЕНИЯ ЗАДАЧ ИНТЕРВАЛЬНОГО РАЗГРАНИЧЕНИЯ ПОЕЗДОВ

The article substantiates technological and technical solutions that expand the application of design standards for railway automation and remote control systems, regulating the development and opera- tion of systems for interval control of train traffic. Based on the analysis of the methods for arranging automatic block signal system and signal signs of automatic train control, used as an independent signaling and communication device during train movement, it has been proved that determining the lengths of block sections at specified train-to-train and intervals reduces the carrying capacity of the hauls. It has been established that a significant increase in the working capacity of the hauls is achieved when determining the lengths of “fixed” block sections by calculating the maximum stopping distances of trains on each haul, and the lengths of the “running” blocks - on the basis of the operatively calcu- lated stopping distances of each ride, passing along the given section. Particular attention is paid to the application of the cognitive (research) method of using the knowledge and experience of interacting railway transport specialists in the field of creation, design and operation of the systems for interval control of train traffic. The directions of development of software for existing and created information systems that serve graphists-technologists, field dispatchers and machinists have been determined. It is shown that the use of the method of simulation modeling of train movement links the times of arrival and departure of trains with the beginning and end of station technological operations, which expands the possibilities of taking into account the influence of technical and organizational factors on the assessment of the working capacity and processing capacity of train stations. It is proposed to supplement the software of the method with a set of algorithms that determine the required working capacity of railway lines, stations, sections, lines and directions for a given number of trains of various high-speed categories, taking into account the prospect of providing possessions for repair work, de- pending on the planned volumes transportation.

Contributions of vehicle dynamics to the energy efficient operation of road and rail vehicles

This review addresses efforts made within the field of vehicle dynamics to contribute to the energy efficient operation of road and rail vehicles. Selected investigations of the research community to develop technology solutions to reduce energy consumption are presented. The study explores the impact and potential of relatively mature technologies such as regenerative braking, but also recent research directions that are seeking to develop solutions such as regenerative suspensions, a concept common to both transport modes. Specifically for road vehicles, the study includes rear wheel steering, camber control and torque vectoring, and for rail vehicles active steering and light-weighting. Operationally, there would appear to be great potential for rail vehicles in the wider adoption of connected driver advisory systems, and automatic train control systems, including the application of machine learning techniques to optimise train speed trajectories across a route. Similarly, for road vehicles, predictive and cooperative eco-driving strategies show potential for significant energy savings for connected autonomous vehicles.

Safe Operations at Roadway Junctions - Design Principles from Automated Guideway Transit

<div class="section abstract"><div class="htmlview paragraph">This paper describes a system-level view of a fully automated transit system comprising a fleet of automated vehicles (AVs) in driverless operation, each with an SAE level 4 Automated Driving System, along with its related safety infrastructure and other system equipment. This AV system-level control is compared to the automatic train control system used in automated guideway transit technology, particularly that of communications-based train control (CBTC). Drawing from the safety principles, analysis methods, and risk assessments of CBTC systems, comparable functional subsystem definitions are proposed for AV fleets in driverless operation. With the prospect of multiple AV fleets operating within a single automated mobility district, the criticality of protecting roadway junctions requires an approach like that of automated fixed-guideway transit systems, in which a guideway switch zone “interlocking” at each junction location deconflicts railway traffic, affirming safe passage. The analogous AV protection safety subsystem is defined as fail-safe equipment that monitors roadway intersections and junctions, communicates traffic signal status, perceives and communicates alerts and signals to AV connected vehicles concerning potential unsafe conditions, and performs related primary safety functions. Conclusions are drawn that the AV protection roadway intersection functions must be performed by local roadside equipment dedicated to protecting each roadway intersection and junction. Further, it is concluded that the communications technology connecting the infrastructure with the vehicle to perform this vital, fail-safe protection should meet specific functional and performance criteria.</div></div>

Research on Real-time and Reliability of Wireless Transmission of High-speed Train Control Data Based on Data Mining Technology

The informationization of high-speed railway is of great significance to the operation and maintenance of high-speed trains. Through the operation and maintenance data communication based on wireless public network, the ground monitoring system can know the real-time status of trains in time, which can facilitate the daily arrangement of inbound inspection and maintenance of trains and improve the operation and maintenance efficiency of high-speed trains. The reliability of data transmission in wireless sensor networks is low under the influence of resource constraints and environmental factors. However, the reliability of data transmission is an important index to evaluate the network performance in application fields such as national defense, military affairs and industrial control. Based on data mining technology, this paper analyzes the real-time, reliability and security of data transmission according to the characteristics of digital mobile communication used for data transmission in railway running and train automatic control. Combined with the characteristics of wireless channel in the environment of intelligent railway transportation system, this paper puts forward concrete measures to improve the performance of wireless link and concrete methods to judge whether wireless transmission can meet the requirements of IRTS environment.