During normal conditions, what does a lit door closed light on the master controller console indicate?

A lit door closed light on the master controller console indicates that all doors on the train are indeed closed. This is a crucial feature for ensuring the safety of passengers and proper train operations. When this light is illuminated, it signifies that the train is ready for operation, with no doors left open that could pose a safety risk when the train begins to move.

The functionality of this indicator is designed to help crew members quickly verify the status of the doors, thereby preventing accidents or delays associated with doors being inadvertently left open. A clear understanding of this indicator's meaning is essential for maintaining safety protocols in train operations.