Intelligent Systems

Wheel Impact Load Detector (WILD)

The original and still the best, Salient's Wheel Impact Load Detector (WILD) is the most widely used system in the world today to manage the wheel impact load spectrum for the targeted removal of defective wheels from service.

The first major step towards truly performance-based wheel management, the WILD continually monitors locomotive and rail car wheel health to ensure safe train operations. With proven accuracy and reliability, WILDs scan millions of wheels per day throughout the international rail industry.

The WILD is a strategic device for the protection of rail infrastructure. Although wheels with extremely high impacts are rare on a percentage basis, small percentages do not equate to small effects. High impacting wheels can dissipate on the order of twenty-five horsepower each, degrading track, ballast and bridge structures while reducing bearing and other vehicle component lives. Over time, the repetitive load cycle of these wheels causes rail fractures. It is not uncommon for system users to see three or four of potentially rail breaking wheels per day across their WILD networks.

Wheel defects with spalling, shelling, slid flat, or out-of-round characteristics impart excessive impact loads. Caught early, they can be trued. Undetected, these wheels can damage thousands of miles of track or cause derailments. Proactive railroads use networks of WILDs to control broken wheels, burnt-off journals, hot boxes, and brake rigging damage by removing high impact wheels, reducing derailments as a result. There is still room for improvement, however: nearly half of all equipment-related derailments could be avoided through greater WILD system coverage.

Complete wayside installation requires no radical modification of existing track structure. A series of strain gage load circuits, micro-welded directly to the neutral axis of a rail, create an instrumented zone for the measurement of vertical forces exerted by each wheel of a passing train. Signal processors, housed in a nearby bungalow, electronically analyse the data to isolate wheel tread irregularities. If any wheel generates a force that exceeds a tailored alarming threshold, a report identifies that wheel for action. Reporting criteria are flexible: for example, a low-level alarm identifies cars for service at the next available opportunity; a mid-level alarm limits a train's maximum speed until the car can be set out; and a high-level alarm directs a train to stop as quickly and safely as possible to avoid a potential derailment. These reports are usually distributed in real-time to such interested parties as rail traffic control centres and car shops.

Salient holds the exclusive, worldwide manufacturing and marketing license from Battelle Memorial Institute, where the original version of the WILD was co-invented by one of Salient's founders. USA and foreign WILD patents define fundamental aspects of the detection process that have proven to be the most useful and reliable. Over the years, substantial proprietary hardware and software developments beyond the basic patent have been incorporated into the existing system.

Our Purpose

Improve the design and supply of products and services required to enhance the performance of rail networks