What condition must be met for block authority when proceeding from a station?

For block authority when proceeding from a station, obtaining a K-card from the block operator is essential. The K-card serves as a tangible authorization that confirms the train's permission to enter a specific block of track safely, indicating that the block is clear and that it is safe to proceed. This process is designed to enhance safety protocols by ensuring that all trains are properly tracked and managed, preventing collisions or unauthorized entries into occupied blocks.

While operational signals and clearance from the dispatcher are important components of train operation overall, they do not specifically fulfill the requirement for block authority in this instance. The K-card acts as definitive proof of authorization from the block operator, making it critical for the safe handling of train movements. Verbal instructions also may not provide the same level of formality and accountability as the official K-card, which is a documented form of authority necessary for managing train movements effectively.