What should not be displayed for other reasons during commission hours?

The correct answer emphasizes that holding lights should not be displayed for other reasons during commission hours. Holding lights are generally used to indicate that a train should stop and wait at a signal. They serve a specific purpose in controlling train movements and safety operations on the railway.

Displaying holding lights at times not required for their intended purpose can lead to confusion for train operators and other personnel. If these lights are shown unnecessarily, it may create uncertainty about the actual state of the track and what is expected of the train crews, potentially compromising safety protocols.

Without the proper context for using holding lights, their presence could disrupt the overall signaling system’s integrity and effectiveness, as each signal color carries significance that guides train operations. Thus, maintaining clarity during operational hours is crucial for the safety and efficiency of railway operations.