This project will examine the concept of introducing coded, differential RF pulses into the rail at grade crossings and, using Time Domain Reflectometry (TDR) techniques, determine the distance to reflections of these pulses caused by approaching trains. Measurements of this train distance information and how it changes over time will be used to predict train arrival time for the activation of grade crossing warning systems. The investigative approach includes the development and bench and field testing of a prototype system. These bench and field tests will be designed to address a number of issues identified in a previous HSR-IDEA project that explored this technology (HSR-38). These included performance of the system near turnouts, bolted and insulated joints, rail welds, the effects of various ballast conditions and concrete ties, and possible interference or damage to or from lightening protection circuits, coded track circuits, EMI, etc. The work plan calls for bench testing at the laboratories of two manufacturers of conventional grade crossing warning systems to confirm compatibility with existing track circuit controllers, and field testing at the Transportation Technology Center at Pueblo, Colorado.
The final report for this IDEA project can be found at:
http://onlinepubs.trb.org/onlinepubs/IDEA/FinalReports/HighSpeedRail/HSR-50Final_Report.pdf
