What is the function of the "Aspect Display Unit (ADU)"?

The Aspect Display Unit (ADU) plays a vital role in locomotive operation by revealing the cab signal aspects directly in the controlling cab. This display provides critical information about the status of signals ahead, allowing the engineer to make informed operational decisions based on the indications shown. The ADU ensures that the engineer is always aware of the current signal aspects, which are essential for maintaining safety and adherence to speed restrictions and other operational protocols.

In a properly functioning railway system, clear communication of signal aspects is crucial for safe train operation. The ADU allows the engineer to visually see this information without needing to divert attention away from the primary focus of the track ahead. This contributes to enhanced situational awareness and safety as the engineer can quickly interpret the signals and adjust train movement accordingly.