What is meant by 'block protection' while granting foul time?

Block protection refers to a safety measure implemented on railway tracks to ensure that no trains are allowed to enter a specific section of track while maintenance or repairs are being conducted. This is vital for the safety of workers who may be on or near the tracks. When foul time is granted, it indicates that a section of track is occupied or restricted for maintenance purposes.

By preventing all trains from entering the area, block protection helps mitigate the risk of accidents, ensuring that employees can safely perform their tasks without the danger of oncoming trains. The other options, while related to safety or communication, do not directly address the vital function of ensuring that the specific track section remains clear of trains during maintenance activities.