Abstract
In the railroad industry, it was estimated by the Federal Railroad Administration’s (FRA) Office of Safety Analysis that over 1,000 train derailments occur every year in the United States, with a significant amount being caused by mechanical failures such as defects within the wheels and tracks. The use of wireless onboard health monitoring technologies as opposed to wayside detection systems has been receiving a lot of attention considering recent catastrophic derailments. Through research, development, and implementation of onboard condition monitoring systems by the University Transportation Center for Railway Safety (UTCRS) and HUM Industrial Technology, Inc., a promising method to detect wheel and track defects has been field tested in freight revenue service. HUM’s onboard condition monitoring system, which includes the Boomerang (the onboard module with a suite of sensors), and the Gateway (the wireless communication module), has improved the visibility of data pertaining to the operating conditions of railcars by measuring vibration data generated by the bearings, wheels, and wheel-track interactions. By correlating these data to measured vehicle speed and GPS locations, the data pertinent to wheel and track aberrations can be parsed and verified against known defect signatures of each component or track. After conducting field tests, the technology was able to detect and locate surface defects on the railroad track at key locations as identified by GPS positioning. By utilizing the Gateway’s real-time GPS tracking, a track defect was identified within 10 feet of the GPS timestamped location of the anomalous impact data. Additionally, the wheel impact data indicated that two wheels had wheel impact load readings at low speeds that correlated with prior data generated on a 2-inch wheel flat from a previous field study. After removing and inspecting the two wheelsets, one wheel was identified with multiple distributed defects, and another wheel was found to contain a wheel flat, characteristic of a skidded wheel. This study highlights the capabilities of onboard condition monitoring systems for determining not only in-situ wheel defects, but extrapolations to track defects and low-speed defect monitoring as well.
