Establishing the Performance Requirements of Rail Vehicle Glazed Bodyside Units: A Suppliers Perspective

Abstract

In the last 7 significant accidents on the railways in GB there have been 60 passenger fatalities. 14 of these have been caused by ejection (passengers being thrown from the train during the course of the collision). One additional fatality was attributed to an object entering the carriage through the train window. In total there have been 26 ejections with over 50% resulting in fatality. The trend has been towards higher speed incidents involving vehicles overturning. The authority responsible for setting Safety Standards and, conducting research on behalf of the Train Operators and Stakeholders in GB’s railways is the Rail Safety and Standards Board (RSSB). They initiated a multi faceted stream of research to investigate the performance of glazed systems in train incidents. The aim of the research was to identify and establish measures which replicate the conditions to which glazed systems may be subject to in collision conditions and to formulate corresponding performance requirements designed to prevent passenger ejection. The research was phased and entailed the following: • Accident investigation and analysis, detailed vehicle examination. • Review of 600 passenger witness statements, obtained by British Transport Police. • Generation of computer models using the MADYMO code and Side Impact Dummy (SID) to model the overturning event in a variety of conditions. • Postulation of events and measures based on analysis. • Proposed test programme. • Construction of new test apparatus. • Construction of existing glazed units — benchmarking process. • Construction of glazed units of improved design utilising different glass specifications and laminations but capable of being fitted into existing frames. • Testing, reporting, stakeholder reviews and the production of a new equipment standard for glass in railway vehicles. The research team was keen to include a glazing company capable of providing the highest level of technical support. Independent Glass, a Scottish company had been making significant strides in improving the penetration performance of glazed units (especially at the extremes of ambient temperature conditions) was chosen to produce glass samples for the project. A significant amount of testing was undertaken at their premises in Glasgow. Additionally the new tests were undertaken which demonstrate improved penetration resistance by heavy objects and improved passenger containment. This research has been embedded in the proposed new RSSB standard “GM/RT 2100” [1] which has developed a new scenario based sequential testing regime for glazed laminated systems in railway vehicles. This paper will inform the audience of these new requirements and the research which led to its introduction. It will show the testing that has been undertaken from the perspective of the glazing manufacturer and will detail the equipment that is required to be able to perform these new tests. It will comment on the cost and mass implications of fitting these new glazing units to vehicles in GB and the safety benefit of doing so. Toughened windows are still being used by some train operators for emergency egress; however most operators are now converting their vehicles to having entirely laminated units in vehicles. This is not the subject of this paper.