To assess rail car operational performance and to identify poorly performing rail cars early, the Washington Metropolitan Area Transit Authority (WMATA) has acquired and installed a Wayside Wheel/Rail Load Detector (WRLD) and measuring system at one of its yards. The WRLD determines truck performance by measuring lateral loads, vertical loads, and angles of attack (and corresponding derived values such as lateral to vertical (L/V) ratios, speed, average car weight, and total train weight) as vehicles and trains pass the detector. The Association of American Railroads (AAR) introduced this technology in one of its research projects in the 1990s. However, this is the first successful attempt to implement WRLD technology for a transit application. A team of WMATA, Booz Allen Hamilton, and TTCI engineers is working to adapt this technology to be effective in the transit environment. Prior to installing the WRLD, the team performed a VAMPIRE® simulation to predict the range of key parameters that was anticipated at the measurement site and on a representative mainline curve. Real-time data collection and information processing allowed immediate access to the curving performance of individual rail cars. The data was used to assess vehicle dynamic behavior during acceptance testing. Data was stored in a database at the WRLD site, and could be accessed via an Internet link. This data was evaluated for generating performance alarms of poorly performing rail cars — an important project milestone, since gaining maintenance personnel’s confidence in the WRLD’s abilities was one of the major objectives. As an early warning device, the WRLD is a very effective tool to identify and select potential “troublemakers” for inspection and preventive maintenance. In addition, the system is also useful for evaluating selected vehicle series and overall fleet performance, by using median and mean single-wheel L/V ratios.

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