During humping operations, before an employee performs maintenance on a bowl track, what must be done?

In humping operations, providing protection against cars being released is critical before any maintenance is performed on a bowl track. This safety measure ensures that no unintended movement of cars can occur while work is underway, which could lead to dangerous situations, including potential injuries to workers or damage to equipment.

By implementing protection measures, such as setting up derails or using other physical barriers, workers can maintain a safe work environment. This protection is essential because humping involves moving cars by gravity, and even minor shifts could result in a cascade of cars rolling unexpectedly.

The other actions, while important aspects of safety and maintenance practices in general, do not directly address the immediate hazards involved in humping operations. Notifying the control operator or closing adjacent tracks might be necessary in different contexts, but they don't specifically mitigate the risk of cars being released during the maintenance procedure. Conducting a visual inspection of the track is also a good practice, though it does not serve as the primary line of defense against the danger posed by potential car movement during maintenance activities.