This project developed a system of acoustic transducers to detect broken rail. Nodes of these acoustic transducers would be installed on the rail at spacings approaching one mile. Each transducer would excite the rail at specific frequencies as well as sense the presence of acoustic energy in the rail. These acoustic nodes would be networked such that each node would relay the data it receives to the next node up the rail to deliver the information to a central control location. Each node could detect reflections from rail discontinuities (breaks) and time the reflections to determine the distance from the node. This information would be transmitted through the rail via the network of acoustic transducer nodes to a control location such as a dispatch center (Figure 1).
The San Francisco Bay Area Rapid Transit District (BART) spent $600,000 on a proof-ofconcept study of this approach under a Cooperative Research and Development Agreement (CRADA) between BART and Sandia National Laboratories. The study is part of the development of an Advanced Automatic Train Control (AATC) system at BART under a $20 million DARPA grant administered by the Federal Transit Agency. Research under the CRADA has discovered a mode of vibration and specific frequencies of excitation that enable acoustic energy to travel distances of more than 2 miles in (continuous welded) rail. The scope of the HSR-IDEA project included recording acoustic signal profiles from various rail discontinuities, including complete and partial breaks, and cracks and flaws, and the development and testing of an algorithm for detecting time of arrival of reflected signals. A prototype system would then be developed and field-tested on BART’s 2.5-mile test track in Hayward, California.
The final report for this IDEA project can be found at:
