Which term describes an arrangement of signals and signal appliances interconnected with interlocking rules?

• A. Interlocking (Int)
• B. Pilot
• C. Aspect
• D. Fixed Signal

Answer: (A)

Interlocking is the coordinated system that ties signals, switches (points), and other related devices together under interlocking rules so that you can’t clear conflicting routes. This arrangement ensures a safe sequence: the route must be locked and verified clear before a signal can show proceed, preventing maneuvers that could lead to collisions. The term you’re looking for describes the whole interconnected setup, not just what a signal displays or what a single device is called. The visible indication on a signal (the aspect) is separate from how signals and appliances are connected; the type of signal (fixed vs movable) is about the physical form, not the interlocking arrangement. The word pilot is not the term for this interconnected system.