wheelset condition monitoring based on pass-by vibration signals

apart from regular wheel wear such as decreasing wheel diameters and reduced flange thicknesses and heights, wheel flats (wf) and oval wheels (or oor, out-of-roundness) are the most common wheelset problems for railway vehicles. within the fp7 research project “saferail”, apt has developed an innovative wheelset monitoring system so-called “wheel flat and out of roundness monitoring (worm) system”. the monitoring system is installed on the track and is based on the vibration signals measured during the passage of trains. the main advantages of vibration signals are the short measurement time of just a few seconds, and the very limited number of sensors to be installed. as a consequence, the track space required for the installation of the equipment is very limited and thus the associated installation cost is significantly reduced. early detection of wheel flats combined with appropriate corrective action not only contributes to lower track stresses and wear, but also results in a longer wheel life. the worm system reports all measured vehicles via a web interface so no user software installations are necessary. a historical overview of measurements and alarms can easily be retrieved from the proposed system. immediate alerts can be programmed to be sent by email or text message. these advantages make the apt-worm system as a strong device to increase the service life of the wheel and decrease the maintenance cost by optimizing the maintenance intervals.