How are flags displayed to protect speed restrictions or men and equipment in a current of traffic?

Flags are an essential safety measure used to alert train crews to speed restrictions or the presence of men and equipment on or near the tracks. The correct answer emphasizes the importance of displaying flags in both directions on main tracks and sidings to ensure maximum visibility and safety.

When flags are displayed in both directions, it provides clear and unambiguous warning to approaching trains from either side. This approach is critical because it accounts for the possibility of trains coming from either direction, thus reducing the risk of accidents. Additionally, main tracks and sidings are integral parts of the railway system, and ensuring that all areas where trains may operate are marked appropriately enhances safety protocols.

Furthermore, restricting the display of flags to only one direction or only on sidings would create gaps in communication and safety, as it could leave some trains unaware of hazards, thus creating dangerous situations. The requirement for flags to be visible in both directions helps maintain a safe working environment for both the railway personnel and train operators.