When is a blue signal displayed, what must not happen with the rolling equipment?

The display of a blue signal is a critical safety measure within rail operations. When a blue signal is shown, it indicates that workmen are actively engaged in work around the rolling equipment. The primary purpose of this signal is to ensure the safety of those individuals by preventing any movement of the equipment.

Thus, rolling equipment must not be coupled or moved while a blue signal is displayed. This rule is designed to safeguard the workers by ensuring that they are not put in harm’s way due to sudden or unintended movements of the equipment. It reinforces the importance of communication and awareness among crew members when it comes to maintaining a safe working environment.