Which code denotes Signal light control?

• A. G
• B. CX
• C. C24
• D. GD

Answer: (A)

In signal maintenance coding, the letters used in orders and tests map directly to the broad type of equipment or control a task involves. The letter G is the designation used for Signal light control, which covers work on the actual lighting and related control circuits of signal lights. This makes it the best fit for a question asking about signal light control, because it identifies the exact category of work focused on the lights themselves.

The other codes point to different systems or components (for example, CX would be tied to crossing-related equipment, C24 to a particular circuit or component, and GD to another function such as grounding or detectors), so they don’t match the task of controlling signal lights.