When delivering a Form D to a train at an interlocking, what is the Dispatcher's responsibility regarding blocking devices?

The correct answer emphasizes the Dispatcher’s duty to ensure that blocking devices are applied at the interlocking when delivering a Form D to a train. This is crucial for maintaining safety and control over train movements. Blocking devices serve as physical indications that prevent a train from proceeding under certain conditions.

When a Dispatcher is responsible for delivering a Form D, they must prioritize the safety of all train operations in that area. Maintaining the application of blocking devices helps mitigate the risk of accidents, ensuring that no train can inadvertently leave the interlocking area while the Dispatcher is conducting their operation, such as delivering a Form D.

This precaution is particularly important as it allows for the proper execution of train movements, ensuring that only authorized movements occur based on the information conveyed by the Form D. By keeping blocking devices in place, the Dispatcher is fulfilling their obligation to regulate train movement safely and effectively until it is clearly appropriate to allow a train to proceed.