What does a Block Limit Signal indicate?

A Block Limit Signal is used to indicate the boundaries of a block within a railroad signaling system, particularly under Manual Block System rules. It plays a critical role in ensuring safe train operations by defining the segment of track that a train may occupy or be restricted from entering.

When this signal is displayed, it serves as a clear indication to a train crew that they have reached the end of one block and the start of another. This boundary is important for the management of train movements, allowing for proper spacing and preventing collisions. By understanding the limitations set by Block Limit Signals, train operators can make informed decisions about stopping, proceeding, or holding at a signal, reflecting the need for safety and coordination in train operations.

The other choices pertain to different aspects of railroad signaling and operations but do not accurately reflect the specific function of a Block Limit Signal in indicating the limits of a block.