In interlocking terminology, fixed signals that protect the limits are also called what?

• A. Home signals
• B. Interlocking signals
• C. Fixed signals
• D. Stop signals

Answer: (B)

In interlocking terminology, the fixed devices that mark and protect the limits of a route are called interlocking signals. These signals are fixed in place and operate under the interlocking logic to prevent any conflicting movements from entering the protected area. They sit at the boundary of the interlocking’s protected route and only show a proceed aspect when the route is properly locked and the signals and points are safely aligned. While other signals in a block system have related roles, the term that describes these boundary-protecting fixed signals within the interlocking framework is interlocking signals.