International Railway Journal - May 2008 - (Page 44)

Measuring & testing vehicle and tested under realistic operating and climatic conditions. This is the only way to detect potential design shortcomings or unexpected interactions between components and systems in specific weather conditions. Rail Tec Arsenal has developed standardised test procedures to identify typical problems encountered by different subsystems during service operation. Insufficient insulation and/or leaks in the vehicle body often have a negative impact on interior temperatures and may cause condensation in the passenger areas or driving cab. In turn, floor surface temperatures in the vestibules may fall below freezing point at low outside temperatures, leading to ice formation. Leaks can be located on the basis of smoke and wind simulation, while insulation problems in the vehicle body, doors, windows or corridor connections can be identified using a thermographic camera. Snow and ice accumulation on door steps can obstruct or prevent opening. The funtionality of these components is tested at freezing temperatures. Windscreens Inadequately-functioning windscreen heater or air inlets in the driving cab can cause the windscreen or side windows to mist up. Snow and ice accumulation impairs visibility and may lead to complete failure of the windscreen wiper, rendering the train unsuitable for service. These problems can usually be eliminated by adjusting the settings of the windscreen washer, wiper and heating systems, and the air-conditioning unit of the driving cab using the results of climatic wind tunnel tests. Bogie components such as dampers, sanding, tilting and brake systems are safety critical components, which are usually very exposed and therefore prone to the accumulation of snow and ice. The possible consequences may range from partial malfunction to complete failure, such ice build-up on the sanding system. All these environmental conditions acting on the underframe components can be realistically simulated on a dynamometer in a climatic wind tunnel. Measures designed to reduce these problems, such as heaters or housing for sanding equipment, can be subsequently tested for their effectiveness. Extremities of temperature, combined with high humidity, typically lead to problems with electric and electronic components such as the main switch, transformer, converter, battery and onboard electronics. Ice build-up usually causes additional mechanical problems with the pantograph. Climatic wind tunnel tests allow these problems to be identified and remedied in good time to ensure reliable functioning of the power supply system during regular service operation. Door and step tests Accumulations of ice and snow in the door area obstruct or even prevent opening, closing or automatic reversal of doors and may cause retractable steps to become stuck. Some targeted design modifications or improvements in the control system are often sufficient to eliminate these problems. In a climatic wind tunnel these measures can be investigated and tested efficiently under reproducible snow and ice conditions. A survey conducted by Rail Tec Arsenal revealed that door and step malfunctions are the most frequent problems reported by train operators. The test procedure for these two components are therefore described in more detail. These components are tested for proper opening, closing and obstacle detection under snow and ice conditions. Ice tests are carried out at ambient temperatures of -20oC. The passenger areas are cold and the air-conditioning unit is switched off. The vehicle doors and the steps are covered with a layer of ice about 2mm thick using a manual sprinkler. Once the last water film has been applied, the ice is allowed to harden for 10 minutes. This procedure is designed to simulate freezing rain. To simulate wet snow, the passenger area is set to regulated mode and a wet snow layer around 20mm deep is Testing coupling operation on two Bombardier Talent emus with 2mm of ice. 44 IRJ May 2008

Table of Contents Feed for the Digital Edition of International Railway Journal - May 2008

International Railway Journal - May 2008 Contents This Month News Transit News Market News Technology News News Analysis Italian Railways on the Road to Recovery High-Speed: On the Home Straight Korea Develops High-Speed Ambitions Setting New Standards for New Rolling Stock India Solves Traction Motor Conundrum Weathering the Storm with Climatic Testing Technology Drives US Train Inspections Rendezvous Full Contact List Advertisers Index The Last Word

International Railway Journal - May 2008

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