What is a requirement for the dispatcher when facilitating a reverse movement?

When facilitating a reverse movement, one of the key responsibilities of the dispatcher is to clear the previous line authority. This entails ensuring that any train that previously had authority to occupy the same track segment is no longer present or has been notified to clear the area. Clearing the line authority is crucial for safety since it prevents potential conflicts between trains moving in opposite directions, especially on tracks where trains could be re-entering or reversing.

This requirement underscores the importance of maintaining safe operational protocols and ensuring that all trains are accounted for before any reversed movement can take place. Without clearing the previous authority, there could be misunderstandings or miscommunications that may lead to unsafe conditions during the reverse movement.

The other options, while relevant to various components of train operation and dispatching, do not specifically address the critical need for ensuring that the previous line authority is cleared before a reverse movement is initiated.