What action is required when passing a solid yellow over a solid yellow aspect?

Answer: C — Proceed prepared to advance on diverging route at next signal at prescribed speed through turnout

The action required when passing a solid yellow over a solid yellow aspect indicates that the train must be prepared to advance on a diverging route at the next signal. This means that the signal indicates a cautionary status, advising the crew to be alert for upcoming changes in track direction or conditions. In this context, proceeding prepared to advance on a diverging route implies that the train will likely transition to a track that is configured differently than the main route, and the crew should be aware of the posted speed limits for that turnout to ensure safety while navigating the change in direction. It's crucial for conductors to understand that a solid yellow signal needs particular attention to prevent accidents or derailments resulting from unexpected turns or speed changes. The other options give different directives that do not align with the meaning of the solid yellow signal configuration. For instance, certain choices suggest specific speed reductions or stopping conditions that are not applicable when the signal indicates readiness to diverge. It's essential for train conductors to receive proper signals to maintain safety and efficient operations on the railway.