Dead-Man'' Device Installed on Trams
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by HAL-Ecole des Ponts ParisTech Questions raised on the design of the "dead-man" device installed on trams Robin Foot, Ghislaine Doniol-Shaw To cite this version: Robin Foot, Ghislaine Doniol-Shaw. Questions raised on the design of the "dead-man" de- vice installed on trams. Cognition Technology & Work, 2008, 10 (1), pp.41-51. <halshs- 00437501v3> HAL Id: halshs-00437501 https://halshs.archives-ouvertes.fr/halshs-00437501v3 Submitted on 8 Apr 2015 HAL is a multi-disciplinary open access L'archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destin´eeau d´ep^otet `ala diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publi´esou non, lished or not. The documents may come from ´emanant des ´etablissements d'enseignement et de teaching and research institutions in France or recherche fran¸caisou ´etrangers,des laboratoires abroad, or from public or private research centers. publics ou priv´es. Cogn Tech Work DOI 10.1007/s10111-007-0076-x ORIGINAL ARTICLE Questions raised on the design of the ‘‘dead-man’’ device installed on trams Robin Foot Æ Ghislaine Doniol-Shaw Received: 2 May 2006 / Accepted: 9 March 2007 Ó Springer-Verlag London Limited 2007 Abstract The reappearance of the tram in French cities When this occurs, the object loses its natural and imper- over the past 20 years has stimulated innovation. Ensuring ceptible character and can once again be targeted. This is the attractiveness of this transit mode has meant conveying the process that Chklovski refers to as ‘‘the estrangement a distinctly modern image of the system. Inherent in the of objects’’1 that is apparently capable of ‘‘providing an resurgence of this transit mode, a safety device, in the form effective antidote to a risk shared by all of us, namely of a monitoring system (the ‘‘dead-man device’’ in rail taking reality (even our own) as a certitude’’ (Ginzburg parlance) intended to mitigate risks related to driver 2001). Under such conditions, the evidence available may blackout, has been reconfigured. This new device, inspired be questioned. by subway systems, has been introduced without inciting We had to face this kind of situation when along came any real inquiry into either the benefits or consequences, in the invention of a new type of urban transit vehicle: the terms of the conductor’s role and transport safety, arising bus–tram hybrid, a streetcar running on tires, in other from such an alternative form of tramway monitoring. An words an intermediate vehicle (between bus and tram). analysis of the process by which the mode of monitoring Featuring a hybrid design with adjustable axles fitted with has been implemented serves to examine and reconsider, at tires and capable of being guided by a central rail or driven least in part, the certification and regulatory system that using a steering wheel, this vehicle resembles the bat in accompanies tramway renovation projects in France. Jean de La Fontaine’s fable that, depending on the cir- cumstances, can assume the form of either a mouse or a Keywords Tramway Á Safety Á Design Á bird. This bus–tram configuration not only carried with it Working conditions Á Dead-man control the innovation of breaking down the barriers that separate road and rail vehicles, but of calling into question the very notion of guidance. 1 Introduction Even if all bus–tram vehicles offer the same character- istic of dissociating guidance from rolling on a roadway, as Some objects seem so intertwined with a particular land- opposed to genuine tramways with rails that serve for both scape that doubting their pertinence or shape would be out guidance and rolling motion, all have not necessarily of context. Their presence is so plainly obvious that they adopted either the same technique for gripping this guid- simply blend into the scenery itself and can no longer be ance rail or the same strategy regarding the exchangeability distinguished. In order to make such objects stand out from between driving modes. the background, an event would have to arise that upsets Some have opted for a mechanical clamping to a central the scenery, that to a certain extent makes it look foreign. rail (e.g., the TVR system by Bombardier, Translohr by Lohr Industrie), which presupposes that the vehicle comes to a stop prior to proceeding with a driving mode change, & R. Foot ( ) Á G. Doniol-Shaw while others have chosen a type of rail grip without any LATTS, ENPC, 6-8 avenue Blaise Pascal, Cite´ Descartes, 77455 Marne-la-Valle´e Cedex 2, France e-mail: [email protected] 1 Quoted by Ginzburg 2001, p 16. 123 Cogn Tech Work mechanical friction (e.g., Siemens’ optical guidance, services has led to deleting all reference to rail, by magnetic control of a preprogrammed trajectory on the substituting the term ‘‘guided mode’’. From a practical Phileas tram produced by the Dutch company APTS). This perspective, this modification has resulted in the de facto latter option, inappropriately referred to as ‘‘immaterial’’, abrogation of the decree issued on 22 March, 1942 that authorizes an instantaneous mode change from a technical ‘‘applied public administration regulations to the policing, standpoint, even though this capability proves more com- safety and operations of rail services designed to benefit the plex from an actual driver’s perspective (Doniol-Shaw general and local population’’ and its replacement by the 9 et al. 2005). May, 2003 decree ‘‘relative to the safety of guided transit This new type of vehicle, capable of being driven using services’’. Since then, tramways are no longer associated two modes as different as a roadway and rail guidance, has with railways, but merely considered as ‘‘public transit however not been fitted with all the safety features man- vehicles constrained to permanently follow a predeter- dated for guided systems. It has been equipped with neither mined trajectory attached to one or several physical rails any kind of sweep guard, i.e., a passive safety device de- running along the roadway’’. In the process that substituted signed to avoid running over pedestrians or cyclists who guided vehicles for tramways, not only had the terminology may have been projected in front the moving vehicle, nor changed, but the philosophy and economics behind system the monitoring control still known under the name ‘‘dead- control as well. man device’’. Such a function is programmed to stop the The transition has thus been made from a management vehicle should the driver be incapacitated to a point of principle based on explicit standards, such as the obligation making him unable to perform system supervision duties, to equip vehicles with a sweep guard or a monitoring de- thereby activating the emergency brake. vice, to a management practice built upon procedures The absence of such safety features stems from the fact requiring system supervisors to ensure that: ‘‘Any new that the transit authority, assigned to oversee application of guided transit system or any modification to an existing vehicle certification and regulation, considered the capa- system must be designed and constructed such that the bility of being operated as a road vehicle sufficient to dictate overall level of safety with respect to users, operating staff this mode as the reference and only submitted them to road- and third parties is at least equivalent to the present level of based certification, thus eliminating the rail-guided mode safety or that of existing systems that provide comparable from the evaluation. This narrow view imposed the obli- services’’. This transition introduces the principle that goes gation that the steering wheel remain active at all times,2 by the acronym GAME (for globally at least the same), in whether the vehicle is being driven in road traffic or guided which standards are no longer explicit but instead pro- on a rail, even though when rail-guided the presence of an grammed into the technical components of situations active wheel compromises safety,3 without serving any adopted as references, which now places the emphasis on navigational purpose. It would take the disastrous startup of evaluating a new system’s overall performance by means of the Bombardier bus–tram, marked by a succession of comparison with a previous system taken as the standard. accidents and the subsequent shutdown of operations for a The complexity of this new procedure, coupled with whole year to improve system safety within the Nancy uncertainties relative to the modes for evaluating the level metropolitan area (eastern France) in January 2001, for the of safety reached, has incited Lohr Industrie to abandon its authority to become aware of the importance of the guided bimodal driving function on its Translohr vehicle, which mode and its unique set of problems. has become the first guided vehicle running on tires to be Revision to the regulatory code specific to urban rail compared with a conventional tramway. The reference transit safety, necessitated by the requirement to adapt situation chosen for this ‘‘tramway on tires’’ will in fact be French legislation to comply with European directives in a tram car rolling on a rail track, i.e., the Citadis produced the aim of creating a single European market, has provided by Alstom, which boasts a recent design and like the the opportunity for the French government to alter its po- Translohr model has a low floor throughout. sition so as to better manage such innovative contexts in Our role comes into play against this backdrop and which the boundaries between modes lack stability. This consists of conducting an expert evaluation of the Trans- process of rewriting the standards that shape urban transit lohr design and, more specifically, of its driver’s cab.