What action must a Dispatcher take until it is confirmed that there is no obstruction on adjacent tracks?

The correct action a Dispatcher must take is to notify all trains entering the block on adjacent tracks before they enter the block. This is crucial for maintaining safety and preventing potential collisions or accidents while there is uncertainty regarding obstructions. Notifying incoming trains allows them to be aware of the situation and take appropriate precautions, such as slowing down or preparing to stop, which is essential when conditions on adjacent tracks are unclear.

The practice of informing trains about potential hazards is a fundamental safety protocol within rail operations, helping to ensure that all crew members are aware of the current conditions. This proactive communication minimizes risks and helps in managing any emergencies effectively.

In contrast, allowing trains to proceed without notification could lead to dangerous situations, especially if there's an obstruction present. Altering the train schedule or consulting the crew could be necessary steps under certain circumstances, but they do not address the immediate need for awareness and caution in the face of potential obstructions on adjacent tracks.