What is the signal to indicate that a work zone is active on the tracks?

Flashing lights and safety cones are established indicators that a work zone is active on the tracks. This visibility-enhancing setup is crucial for ensuring the safety of both workers on the site and passing trains. The flashing lights alert oncoming trains and their operators to the presence of work and the potential need for caution or reduced speed. Safety cones further delineate the area where work is being conducted, providing a clear visual barrier and indicating that the area should be approached with caution.

In contrast, while a whistling sound from the locomotive can signal various messages, its function is not specifically designated for active work zones. Static train signals typically provide information on track status rather than providing notice of an active work area. Sound warnings from workers can assist in communication but are not formal indicators by themselves, lacking the standardized visibility and effectiveness of flashing lights and safety cones in ensuring a safe work environment.