Which term describes a switch that is controlled within interlocking limits?

• A. Block Station
• B. Bulletin Notice (BN)
• C. Interlocking Switch
• D. Passenger Station

Answer: (C)

Interlocking governs how switches and signals work together to keep trains from conflicting routes. If a switch can only be moved under the control of the interlocking system and is locked or permitted to move only when a safe route is set, that switch is an interlocking switch. The interlocking checks that the signals display a proper aspect before allowing the switch to move, and it locks the switch in place once a route is established. This ensures movements stay within safe, approved limits. The other options don’t describe a switch under interlocking control: a block station is a location in the block system, a bulletin notice is an informational notice, and a passenger station is a station building.