When can an extra train operate without Form L authority in single track territory?

The reasoning behind this choice being correct lies in the operational standards established for extra trains in single track territories. In railway operations, yard limits are designated areas where specific operating rules apply, allowing for increased flexibility in train movements. When operations occur within yard limits, proper signal indication communicates to train crews that they may proceed without needing separate Form L authority, which is typically required for extra trains to ensure that all movements are properly authorized.

This allowance recognizes the unique conditions of yard limits, where trains may be frequently entering and exiting, and where operational fluidity is paramount. Crews must still adhere to all signal indications, ensuring safety and coordination among trains operating in these zones. This reduces the administrative burden for crews and dispatchers while maintaining safety and efficiency.

Other choices do not align with the established guidelines. For instance, operating an extra train only in emergencies or during night operations would not provide the consistent framework needed for regular train schedules and movements, failing to address safety protocols effectively. Similarly, instruction from the dispatcher, while certainly important, does not negate the requirement for Form L authority outside of specific indications, such as those found in yard limits.