The constant movement of trains over tens of thousands of miles has an unrelenting effect on many car components. One of the components most susceptible to catastrophic failure due to this constant rolling friction are the wheel bearings. Over time, these carefully machined roller bearings may crack, spall, and even seize with resulting effects on fuel economy and, most important, on train safety. Seized bearings are associated with locked wheels that cause the wheel to drag on the rail. This can result in fires, damaged rail and wheels, and even train derailment.
The most common approach to monitoring wheel bearing is through use of “hot box detectors” placed at regular intervals along the rail. These simple devices detect when a bearing is too hot and notify the train operator. Because the time between detection and catastrophic failure is short (perhaps only a few miles of travel), these hot box alerts require that the train be stopped immediately, affecting schedules not only for the subject train, but also any other trains needing the same track.
Unfortunately, hot box detectors are notorious for false alarms. The cost of stopping a train and evaluating the condition of the bearings can reach into tens of thousands of dollars per false alarm.
IEM has developed a range of products aimed at addressing this problem of false alarms.
