When must track and time be released?

The correct answer emphasizes the importance of adhering to a specific timeframe in railway operations. Track and time must be released before the granted time expires to ensure safety and operational efficiency. This practice is vital as it prevents delays in train movements and allows dispatchers to manage the track effectively, keeping the railway system coordinated and minimizing risks of accidents or incidents associated with unauthorized access to sections of track.

Releasing track and time before it expires helps maintain a disciplined approach to train operations. It allows other trains or maintenance activities to access the track as soon as it is no longer being utilized, thereby facilitating smooth and continuous operations across the network.

In contrast, the other options suggest less structured approaches. Discretion of the crew can lead to delays or miscommunication. Waiting for paperwork to be completed before releasing track and time can slow down operations unnecessarily. Releasing track immediately when the last car leaves might not account for any safety protocols that need to be followed, making it potentially risky. Thus, timely release of track and time is essential for both safety and efficiency in train dispatching operations.