Which fixed signal indicates the limit of the block, with use governed by manual block signal system rules?

• A. Block Signal
• B. Distant Signal
• C. Fixed Signal
• D. Block-Limit Signal

Answer: (D)

In manual block signaling, trains are governed by fixed signals that define the boundaries of each block. The signal that marks the end of the current block and the start of the next one is the block-limit signal. It serves as the boundary indicator, letting crews and dispatchers know where the authority of the current block ends and the next block begins. This distinction is crucial for safety because movement into the next block must follow the appropriate authority and protect that block as required by manual block rules.

This is different from a block signal, which tells you whether the block ahead is clear or not; a distant signal alerts you to the approach and the aspect of the next block signal; and a fixed signal is simply any signal anchored to a fixed location, not specifically indicating block boundaries. The block-limit signal is the one that specifically marks the block’s limit under manual block rules.