Which types of signals can display an aspect of advance approach?

The correct answer is that both position light and color light signals can display an aspect of advance approach. An advance approach signal informs train crews of the upcoming signal that will likely indicate a restriction or stop. This is crucial for proper train operation, allowing engineers sufficient time to react appropriately.

Position light signals use distinct configurations and illumination patterns to convey routing information, including advance approaches, especially where traditional colored aspects may not be feasible. Color light signals, on the other hand, utilize specific colors to indicate the same aspects, including cautionary signals for an upcoming stop. The versatility of both types of signals to convey advance approach aspects is essential for maintaining safety and efficiency on the railway.

This functionality in both signal types ensures that train crews receive timely warnings about the conditions ahead, which is vital for safe operation and decision-making.