HV is the code for which description?

• A. Home relay ( slotting )
• B. Caution signal light control
• C. Signal can clear relay light on interlocking machine
• D. Home signal clear stop relay

Answer: (D)

The key idea is understanding how signaling code abbreviations map to specific relay functions in interlocking. HV is the designation used for the relay that handles the relationship between the home signal and its stopping logic—i.e., the home signal clear stop relay. This relay is part of the interlocking that ensures a home signal, when cleared, is safely linked to the route and stopping functions, preventing unsafe movements if the route isn’t properly set or if the home signal isn’t actually clear.

So the best match is the home signal clear stop relay because it directly describes the function tied to the home signal’s clearance and the associated stop/control logic in the interlocking. The other options refer to different parts of signaling logic—slotting, caution-light control, or a relay related to lighting—rather than the specific home-signal clearance and stop relation that HV denotes.