Safety Enhancement of Railway Traffic by Modern Supervision Systems F. BELMONTE, K. BERKANI, J.L. BOULANGER, W. SCHÖN Université de Technologie de Compiègne (UTC), Laboratoire HEUDIASYC, B.P. 20529 F-60205 Compiègne, France. Abstract New generation of supervision systems in industry can achieve operation from display process variables to all automated control where human is just monitoring automaton. In railway specific industry, supervision is organised in switching zones and aims to be centralised in an Integrated Control Centre. Such centres implements integrated and computer based systems that perform train protection, train operation and supervision. Thus railway dispatchers using supervision have their tasks considerably simplified. Although considered today as not safety critical, railway supervision systems can contribute to safety in some scenarios where an appropriate decision of a supervision operator could notably reduce the severity of accidents. That is in particular the case for residual scenarios (intervention of maintenance teams on the tracks, manual operation of trains not protected by train protection system, coupling / uncoupling, emergency requiring the stop and the evacuation of a train…) only covered by procedure, thus requiring a human intervention by a person supposed correctly informed on the state of the system, thanks to the data provided by the supervision system 1. Introduction Whatever the degree of human presence aboard trains, all railway lines have however a system which centralizes for operators of a central room, as well the operations of traffic control (signalization, traced routes etc.) as operations of traffic regulation. Formerly analogical, today technology is becoming numerical. Thus, it is now possible to generalize the centralization of many functionalities formerly carried out locally by operators on-site (signals and switching devices handling, traction energy management, disturbance management, public places monitoring). Train Control Centres have evolved over time to include many other functions than the initial ones of tactical and strategic control over the traffic network. In keeping with technological developments, customer requirements on Train Control Centres have become ever more sophisticated, requiring increasing numbers of functions in order to extract the best from their existing assets. In the same way, low cost systems are now requested, offering increased functionality for a given cost. Facing the need for cost reduction, instead of purchasing a Control System for each type of application (traffic, energy, auxiliaries, telecommunications etc.), customers now request just one control system able to offer a fully integrated feature set. This technological development improvement must be accompanied by an evolution of operator’s culture. On the one hand, the increasingly frequent use of numerical technology in safety functions requires rigorous process development. On the other hand, the activity of human operators changed much: operators on-site (drivers, pointsmen) are becoming more and more supervisors of automats. They must apprehend, analyze the remote situation and as far as possible often act with the help of remote controls. This paper first presents a state of the art of modern industrial supervision systems, including the widest possible panel of activities (urban and intercity railway, civil and military nuclear applications, chemistry, air traffic...). As an illustration of consequences of inappropriate actions or decisions, accidental scenarios where supervisors decision could have play a role on the severity of consequence are analyzed. In particular the accident that occurred in Suburban Station “Gare de Lyon” in Paris in 1988: June 27, 1988 will be analyzed. The paper will then present experimental results performed using a modern railway supervision platform similar to a real one (ALSTOM Transport’s supervision product: ICONIS™), installed in Compiègne research centre. Using this platform, it is possible to re-create in laboratory real accidental scenarios, and to be able to confront human operators with these situations, in order to analyze their comportment and their decisions. 2. State of the art of modern industrial supervision systems Industrial process supervision covers a wide range of applications, from simple control to complex and heterogeneous system control. Industrial process could be defined by whole actions animating the system to achieve a task. For example railway transportation process is defined by all sub-systems operations (tracks, trains, energy, driver …) that transport passenger or freight in time and safely from one place to another. Usually processes are classified by the nature of the set of their representation variable. A representation variable evaluates or measures an action in the process. For example in railway traffic process the set of representation variables includes all variables that describe the traffic as the number of trains on tracks, occupancy of each track section, late or advance in daily program , etc. If each representative variable has a countable definition domain, the process is called discrete, else if it is uncountable the process is called continuous, finally if the set of representative variable contains discrete and continuous variable the process is known to be hybrid. The aim of this section is present the industrial survey on supervision of each representative class of process including of course railway applications. 2.1. Industrial survey A general industrial supervision survey was performed from March 2005 to January 2006 (see Table 1). Company Places visited Domain What to supervise CEA LIL (Laser line integration) High technology, defence and Sequential actions to perform prototype experiment one shot LMJ (Laser Mega Joules) High technology, defence and Sequential actions to perform experiment one shot CFF Computer-controlled all-relay Mainline railway transport Route control interlocking Lausanne’s station Regional operation process Mainline railway transport Traffic flow control CRNA-Nord North French air traffic control Aerial transport Route control EDF (CIPN) Nuclear power plant engineering Energy production Power plant RATP Centralized Traffic Control CTC Metro transport Route control & Traffic flow (Bourdon) control CTC RER A Urban railway transport Route control & Traffic flow control CTC 14th line (METEOR) Automatic metro transport Route control & Traffic flow control Company Places visited Domain What to supervise CTC 4th line Metro transport Route control & Traffic flow control SANOFI- Vitry (94) production unit Pharmaceutical, chemical industry Discrete or continuous AVENTIS chemical processes SNCF Computer-controlled all-relay Mainline railway transport Route control interlocking Paris Montparnasse station Centralised traffic control of French’s High-speed railway transport Route co ntrol & Traffic flow South-West high-speed line control Transpole CTC Lille Automatic metro transport Route control & Traffic flow control Table 1: Industrial supervision survey The visit of the engineering centre of nuclear production has revealed that everything is controlled from a single control room. In this room, the operators vary the electrical power emitted according to the consumers needs and the reactor behaviour is managed regardless the operating mode. The computerized supervision is a specific post of this room. It is not related to the reactor behaviour. Although non critical for safety, this system is very appreciated by the operators because it provides information allowing the checking of the analysis carried out starting from the conventional instruments without the data processing assistance. Being unable to prove the reliability of the information provided by the computer based supervision, the use of this one in a situation of preservation of nuclear safety or safety of the auxiliary systems and people is formally prohibited. The use of such a system of supervision is a help which makes it possible to the operator to release a little bit his cognitive resources. The continuous formation of the operators and the regular carrying out of crisis simulations on simulator is very significant in order to guarantee the training and the effectiveness of the operator facing a real degraded situation where the assistance systems are no more used. Within the framework of the medicine (drugs) product ion, the SANOFI-AVENTIS company implements supervision activities of its workshops of production or of management of general flows (water-nitrogen- oxygen). The manufacturing unit is made up of heterogeneous workshops. On the one hand, the treatment processes can be continuous or discrete and on the other hand the supervision systems of each workshop are supplied by different industrialists. The monitoring and the control of a workshop are integrated in the same system. This system is always centralized in a supervision room but can be locally redundant for a particular tool. The workshops are reconfigurable and thus the supervision systems too. The safety requirements evolve according to the products to manufacture. A safet y constraint can be transformed to an operation rule according to the preparation in progress. The reconfiguration campaigns are long and heavy tasks to validate. All the wiring of the relay cards guarantee safety and the alarms treatment is completely redone. The Laser Mega Joules (French Atomic Energy Commission, LMJ is still in construction) will be a single