What aspect indicates that a train can proceed but must be prepared to pass the next signal at restricted speed?

The aspect that indicates a train can proceed but must be prepared to pass the next signal at restricted speed is known as "Approach Restricting." This signal aspect provides critical information to train crews reminding them that while they are allowed to move forward, they need to be cautious and prepared for any conditions that may require them to stop or slow down significantly upon reaching the next signal.

"Approach Restricting" often means that the following signal might be set at "stop" or another restrictive aspect. By instructing the train crew to operate at restricted speed, it ensures they can safely control their train’s speed to react appropriately to the upcoming signal or any potential hazards ahead. This is essential for maintaining safety and preventing accidents on the railroad.

In contrast, the other choices signal different conditions. "Diverging Clear" signals that the train can proceed through a diverging route without any restrictions; "Clear" allows the train to proceed at normal speed; while "Stop and Proceed" requires the train to come to a complete stop before proceeding cautiously. Each of these signals communicates different operational requirements that do not prepare the crew for potential restrictions at the next signal like "Approach Restricting" does.