If you are stopped by a hot box detector, what type of test should you perform after setting the car out?

When a train is stopped by a hot box detector, it indicates that there may be an overheating issue with one of the wheel bearings on the train cars. After setting the affected car out of the train for further inspection, it is essential to conduct a Class III test. This type of test involves a thorough examination of critical components, such as wheel bearings and axles, to ensure safety before the car can continue its journey.

A Class III test is specifically designed to closely scrutinize the areas that could be impacted by any potential overheating, thereby mitigating the risk of mechanical failure or accidents. This makes it the appropriate choice following a signal from a hot box detector, as the focus is on safety and maintaining operational integrity.

In contrast, the other test classifications focus on different levels of inspection that may not be as intensive or appropriate for the immediate concerns raised by overheating indicators.