If you see an imperfectly displayed signal showing yellow over red over dark, how should you operate?

When encountering an imperfectly displayed signal that shows yellow over red over dark, it is important to understand the meaning of the signal's aspects. The yellow over red indicates that the train must prepare to stop, with the expectation that the subsequent signal may be more favorable.

Operating according to the approach signal means that the train must be prepared to reduce speed and be ready to stop at the next signal. This action aligns with typical procedures in rail operations, which prioritize safety and the need to be prepared for potential obstructions.

Understanding that the combined aspects indicate a risk factor, operating based on the approach signal allows the train crew to maintain vigilance and readiness to react to the following signal's indication. Considering the context of rail operations, this choice ensures that the train can safely navigate the track ahead while adhering to protocol for imperfect signals.