Key Findings

• A survey of leak detection methods used in fluid transport systems revealed three categories that have some potential applicability to train BP leakage and/or freight car brake systems: hardware-based, software-based, and tracer gas methods.
• Hardware-based leak detection methods, such as acoustic sensors, require advanced signal processing techniques to correlate sensor data to pinpointed leak locations. Until onboard sensors that monitor brake pipe flow and/or pressure are prevalent on freight cars, wayside sensors likely hold the most promise for leak detection at the train level.
• Software-based leak detection methods require a detailed understanding and modeling of the brake system components being assessed and can also require additional monitoring in the brake system. This method is likely to require more research than the other methods reviewed.
• Tracer gas is currently being used on truck air brake systems and could have the potential to improve leak detection at the car level, however, its long-term effects on both brake system components and workers need to be considered further.