What does the method of operation "Restricted Speed" require stopping within?

The method of operation known as "Restricted Speed" is a safety protocol that requires a train to operate at a speed where it must be able to stop within half the range of vision. This means that if a train is traveling under restricted speed, the engineer should be able to see any potential obstacles or signals that may affect the safe movement of the train within that distance.

This method is particularly essential in situations where visibility may be limited, or where there may be track maintenance or other hazards present. Therefore, having the obligation to stop within half the range of vision promotes a higher level of situational awareness and caution, allowing for safe operations in various environments.

In contrast, other options like stopping within one mile or requiring signal indication do not precisely align with the definition of restricted speed. The requirement to stop "under any condition" is too broad and does not realistically fit the restrictions placed on a train operating under restricted speed, since it focuses specifically on the train's ability to stop within its range of vision.