In high-water conditions, when is it safe for a train to use the tracks?

The option stating that it is safe for a train to use the tracks when inspected and verified safe is correct because safety inspections are crucial in determining the integrity of the tracks and surrounding areas. High-water conditions can lead to various hazards, such as washed-out tracks, erosion, or underwater obstructions that are not immediately visible. An official inspection ensures that any risks are identified and adequately assessed before allowing train operations to resume.

The other choices do not provide a reliable basis for ensuring safety. For example, waiting only until the rains stop does not take into account the potential for continued hazards that may arise after the precipitation ends. Similarly, restricting train use only to daylight hours does not guarantee safety, as conditions can remain hazardous regardless of the time of day. Approval from a mechanical supervisor may be necessary for certain operational decisions, but without a thorough inspection, it may not adequately ensure track safety under high-water conditions. Thus, the emphasis on inspection is vital for safe rail operations.