TTC OPERATED BY ENSCO
AUTOMATED ROLLING STOCK
INSPECTION WITH WAYSIDE AND ONBOARD TECHNOLOGY olling stock inspection and monitoring are essential to safe and efficient railway operations for both freight and passenger trains. Today, a variety of wayside and onboard inspection technologies are used to automatically assess components such as bearings, wheels, and trucks, as well as systems that monitor the overall condition of a railcar. The East Palestine derailment highlighted the importance of automated rolling stock inspection in ensuring public safety. In the years ahead, wayside and onboard technologies will remain a central focus of the railway industry. This article explores current inspection technologies and emerging needs. BEARING INSPECTION TECHNOLOGIES Railcar bearings can experience various types of defects which can result in increased temperature. In some instances, a defective bearing can rise in temperature to the level of causing a bearing burn off, where the bearing and journal melt causing the railcar to be compromised and increasing the risk of derailment. Common root causes of defective bearing conditions include spalling on 38 Railway Age // June 2025
the raceways of the bearing, fretting between the bearing components and journal causing loose conditions of press fit components, and cracking steel roller cages caused by repeated wheel impacts from a slid flat wheel. High temperatures in defective bearings can be detected by Hot Bearing Detectors (HBD), also known as Hot Box Detectors, which use infrared sensors to measure bearing temperature as a train passes. If a bearing exceeds a set temperature threshold, the detector issues a warning to the train crew via radio and sends data to a central operations center for further analysis and potential intervention. Potential defects in a railcar’s roller bearings can also cause the bearings to generate abnormal sounds that can be detected by Acoustic Bearing Detectors (ABD). An ABD uses specialized microphones mounted in or near the track to detect and categorize the sounds generated by defective bearings such as spalling in a bearing’s cup, cones, or rollers. A third method, onboard monitoring, involves mounting small sensors directly onto the bearing adapter. These devices typically measure temperature and acceleration, providing continuous real-time data as the train operates.
WHEEL INSPECTION TECHNOLOGIES Train wheels can develop several types of defects, including flat spots, out-of-round wear, spalling, shelling, and built-up tread. These irregularities can cause repeated impact forces when the wheels turn, increasing the risk of damage or failure. Wheel Impact Load Detectors (WILD) use strain gauges or similar sensors attached to the rails to measure the force of these impacts as the train passes. Wheel profiles can also wear down in ways that increase derailment risk, such as thin flanges, thin rims, or hollow treads. Wheel Profile Detectors (WPD) use lasers and cameras to capture the shape of each wheel, providing valuable data to ensure they remain within safe limits. This data also supports predictive maintenance by showing how wheel wear evolves over time. TRUCK, BRAKE, AND DRAFT SILL INSPECTION TECHNOLOGIES Various conditions can cause truck hunting, such as hollow worn wheels, worn friction wedges, and out-of-tolerance side bearings in combination with empty railcars operating on tangent track at higher speeds. This form of suspension motion results in a railcar’s truck railwayage.com
TTC Operated by ENSCO
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BY TRAVIS GORHUM, SENIOR RAILWAY RESEARCH ENGINEER, ENSCO, INC.