What does the term "ghost circuit" refer to in this operational context?

In the context of tower operations and signaling, the term "ghost circuit" refers to an illuminated light with signals. This phenomenon occurs when a signal programmed to indicate one state (such as "clear" or "stop") unexpectedly shows another state due to interference, faults, or misinterpretation. The appearance of a ghost circuit can confuse operators, as it may convey an erroneous message that could lead to operational misjudgments.

The ghost circuit typically manifests when there are issues in the electrical or control systems that result in signals showing incorrectly, thereby illuminating lights that do not correspond to the actual conditions on the tracks. Understanding this concept is crucial for tower operators to recognize potential signaling issues promptly and take corrective actions to ensure safety in train operations.