When all three amber lights above the platform are illuminated at a gap station, what does this indicate?

When all three amber lights above the platform are illuminated at a gap station, this signals that the conductor must keep the doors of the train open. This indication is crucial for ensuring safe boarding and alighting of passengers, especially in situations where there may be a gap between the train and the platform. The illumination of these lights serves as a direct instruction to the train crew regarding door operations, enabling smooth passenger flow and avoiding unsafe situations.

The correct interpretation of this signal is essential for maintaining operational safety and efficiency at gap stations, where the risk of accidents can be higher if passengers attempt to board or alight through closed doors or without appropriate guidance.