What does a top green and bottom red signal indicate in NSW RVDS double colour light territory?

A top green and bottom red signal in NSW RVDS double colour light territory indicates caution, specifically that the next signal will show stop. This configuration signals to the train driver that while their current signal is clear for a short distance, they should be prepared to slow down and stop at the next signal. It's essential for train operators to be aware of this indication, as it helps them to anticipate the conditions ahead and respond appropriately, ensuring safe operations along the track.

Other potential signals could point toward different scenarios, such as a complete clear to proceed with no restrictions, reduced speed, or a stop condition that would imply a more immediate need to halt. However, the unique combination of this signal allows for a clear warning that the following signal will not permit further movement, emphasizing the importance of vigilance and readiness to decelerate.