Integrated Distributed Intelligent System for Rail Automation: Safety Issues
Total Page：16
File Type：pdf, Size：1020Kb
Journal of Traffic and Logistics Engineering, Vol, 1, No. 2 December 2013 IDISRA – Integrated Distributed Intelligent System for Rail Automation: Safety Issues Asim K. Pal Indian Institute of Management Calcutta, Kolkata, India Email: [email protected] Debabrata Nath Neotia Institute of Technology Management And Science, Kolkata, India Email: [email protected] Abstract—A novel Integrated multi-layered network and security backup. The communication system needs to cooperative computation based Distributed Intelligent System involve railway hardware and equipment of a great for Rail Automation, IDISRA, is proposed for safe, reliable, variety and a highly complex and vast network covering efficient and automatic train operations. The objectives are, several hundreds of railway stations with tracks running i) distributing the load from a central server located at a thousands of kilometers sometimes across nations or signal house to a neighbourhood of nodes to avoid bottleneck, ii) making the signals intelligent having to-and- continents, thousands of signals, operating staff in fro communication, storing and analyzing capability, iii) thousands, hundreds of trains running at variety of speeds integrating the communication mediums from rail to optical and carrying millions of passengers on daily basis. The fiber to wireless sensors to enable multi-layering of the computation is required for automatic control of the network, and iv) integrating the multi-layered network speed and direction of the train on a real time basis to based on p2p communication and nested addressing system maintain the schedule and smooth passage of the train, to enable cooperative computation for local and instant e.g. reducing the train speed due to bad condition of track decision making. The multi-layered network combines or weather, selecting the track or making last minute networks like signal network, station network and junction changes to the route due to temporary closure of some network. This system can monitor and control local incidents through intelligent signals and sensors to detect sections of the rail network. A smooth, safe, automatic, early and recover from any emergency situations like node reliable and efficient operation of train movement along failure, track hazards, fog, fire, collision, sabotage and with adequate provision of manual intervention helps in terrorist activities by providing alternative backup solutions. maximizing overall train speed and minimizing casualties. IDISRA is basically a founding block based on which an A NEtwork-based Signal Control System for overall train operations management system including Automatic Block Signals is discussed in [1] on the basis automatic train movement can be developed. The system of a signalling system that controls the field devices eliminates most existing external trackside equipments. The through an IP network [2]. These technologies use current work focuses on the safety related issues of IDISRA. centralized control system to operate the interlocking and Index Terms—Cooperative computation, fault tolerance, their corresponding signals. An application of assurance multi-layered network, p2p, sensor, signalling technologies that is necessary to coexist with the existent interlocking device over the period of construction and operation is described in [3]. It consists of a central I. INTRODUCTION control unit called LC (logic controller) and terminal devices called FC (field controller) that are distributed at There are wide ranging causes of train accidents which the trackside and operate signal devices. The Internet and include human failure, track damages, failure of the optical LAN technologies are used for communication engine, coach coupling, signal or interlocking unit, between a LC and corresponding FCs. Here the term communication network failures, information security ‘distributed’ is used to imply the scattered position of the breaches, natural calamities, sabotage and terrorist FCs. A recent work [4] describes a railway signalling actions. The systemic reason behind accidents is the poor system utilizing ip-based communication network and state of operation, maintenance, management, quality of autonomous technology being implemented in a Japan equipment and communication network or faulty design railway. The FC decodes the control data from the LC of the system. The central issue involved in designing a and electrically controls the signal device's behaviour. system for smooth operation of automatic train The FC then returns the result data back to LC. The FC movement is the communication network and the also monitors status of the signal device and sends a efficiency of the computation supported by proper monitoring data to a remote server. From the above it is seen that currently the railway Manuscript received December 30, 2012; accepted January 25, 2013; signalling systems are basically centralized systems revised February 28, 2013. ©2013 Engineering and Technology Publishing 179 doi: 10.12720/jtle.1.2.179-183 Journal of Traffic and Logistics Engineering, Vol, 1, No. 2 December 2013 which have some inherent weaknesses affecting overall full description particularly of the network and performance associated with centralized control and addressing mechanism is not within the current scope. operation. These are heavy load and bottleneck at the The structure of the paper is: Section II and III outline servers, frequent system crashes, and lack of flexibility in IDISRA and its communication infrastructure. Section IV designing systems. A distributed system on the other discusses how the safety issues are addressed in the hand has been found to be more efficient and reliable, existing systems, while V focuses on how the safety scalable, flexible (e.g. it can add or adapt to newer issues are resolved by IDISRA and also explains its fault networks or systems), allows point to point connectivity, tolerance mechanism and handling of emergency empowers locality of operation and more equitable situations. Section VI concludes with scopes of research. sharing of resources and thus enables cooperative and intelligent computation. Each of these features is suitable II. IDISRA for a big and mixed network like that of a railway system. We thus propose a distributed system as follows. The objective of IDISRA is to make the signalling A novel Integrated multi-layered network and system intelligent being reactive and responsive in real cooperative computation based Distributed Intelligent time to the immediate situation arising from incidents System for Rail Automation (IDISRA) where the occurring locally. This is achieved through a p2p based computations and communications are mostly local communication mechanism. Train movement monitoring (Locality here is defined according to the level of the and control and operation of interlocking units are network that the node belongs to.) is proposed. The accomplished by means of cooperation between the computation would be carried out by autonomous yet stations and signals. cooperating agents representing entities such as moving In this paper we focus mainly on the safety issues. Our trains, signals, track interlocking units, stations and even communication network has four levels (layers) and five human agents like drivers and station masters. types of nodes: junction, station, signal, trackside sensor Neighboring agents directly communicate with each other and train, all except the train have fixed location. At the like peers for a cooperative cooperation required, e.g. for highest level is the junction network with junctions as determining the speed of the train or directing the nodes, next station network with stations as nodes, then interlocking unit for allocation of a track to the signal network and lastly sensor network. Wireless sensor approaching train. The neighbourhood structure is devices are useful to monitor any incidents occurring dynamic because of continuously shifting locations of locally. WSN (wireless sensor network) is introduced to moving trains. We propose to use our own addressing reduce the occurrence of accidents and improve the mechanism unlike many recent systems which use ip- efficiency of maintenance activities [6]. Existing wireless based networks [1]-[4]. The problems mainly security techniques used for both communications and signalling with using ip-address for railways were mentioned as in the railway industry and low-cost, low-power WSN early as in 2003 [5]. architecture to monitor the health of railway wagons attached to a moving locomotive is described in [7]. A. Contribution In our system all communications occur between peers IDISRA uses a multi-layered network which integrates according to a defined neighbourhood structure. constituent networks as sensor network (at the lowest Neighbourhood of any node is in general a function of level), signal network (at the next level), station network, node type, incoming train location, train route, train type junction network, and so on. This is a p2p based (high/low speed), train requirement, and decisions taken distributed network. It uses a nested addressing system. by the approaching station. When a high speed train Each node has a well defined neighbourhood which either moves the neighbourhood defined till the next station spans the network at the same layer as the node belongs may not suffice as more planning may be required to or spans across other layers depending on the need. compared to low speed trains. For inter-level The neighbourhood