What must all movements within yard limits be made at unless under favorable block signal indication?

All movements within yard limits must be made at restricted speed unless there is a favorable block signal indication. This requirement is essential for ensuring safety within yard operations, where the presence of workers, equipment, and other trains can create unpredictable hazards.

Restricted speed allows trains to proceed at a speed that enables them to stop short of any obstruction. This precaution is crucial in yard environments, where visibility can be limited due to various factors such as the layout of tracks, conditions of the yard, and the potential for unexpected obstacles or personnel. By adhering to restricted speed, operators maintain the ability to react swiftly and safely to any situation that may arise.

In contrast, other speeds—such as normal speed, high speed, or approach speed—do not offer the same level of safety assurance within the complex environment of yard limits. They can increase the risk of accidents, as they may not allow sufficient time for a train to stop if an obstruction or hazard is encountered suddenly. Thus, the requirement for restricted speed is a fundamental safety protocol in railroad operations, ensuring that movements are performed with the necessary caution and preparedness for unexpected situations.