What does signal clearance mean and when is it granted?

• A. A permission to bypass a signal.
• B. Permission for a train to occupy a block or proceed past a signal; granted when the route and safety checks are complete.
• C. A signal indicating to stop.
• D. A maintenance instruction.

Answer: (B)

Signal clearance is the authorization for a train to proceed into the next block or past a signal, after the route ahead has been prepared and all safety checks are complete. It represents that traffic routing and interlocking have verified the path is safe, with the route set, signals aligned, and any points properly locked, ensuring no conflicting movements. Only when these conditions are satisfied is clearance granted, allowing the train to enter the block or pass the signal.

This description matches the idea of a go-ahead that depends on a fully prepared and verified route. It is not permission to bypass a signal, not a signal that tells a train to stop, and not a maintenance instruction, all of which would indicate different, unsafe or unrelated actions.