What role do visual signals play in train operations?

Visual signals are critical in train operations as they provide essential information about required stops, track conditions, and other important operational directives. These signals help locomotive engineers and train crews understand the safe course of action at any given moment during a journey. For example, visual signals can indicate whether a train must stop, proceed with caution, or continue at full speed. They also relay information regarding track conditions, such as whether a track is clear or if there are any restrictions or hazards ahead. This information is vital for ensuring the safety of the train, crew, passengers, and the surrounding environment.

The other options do not accurately capture the primary function of visual signals in train operations. While maximum speed limits are important, they are typically communicated through other means such as speed signs and not solely through visual signals. Passenger entertainment is not a function of operational signals; they are focused solely on safety and operational directives. Additionally, determining the weight capacity of a train involves other safety and engineering considerations and is not a role played by visual signals.