What is required when a switch is undergoing repairs in CTC or manual interlocking limits?

When a switch is undergoing repairs within Centralized Traffic Control (CTC) or manual interlocking limits, it is essential to prioritize safety and communication. Notifying the control operator and displaying stop signals is crucial because it ensures that all train movements are halted in that area, preventing potential accidents. By informing the control operator, you allow them to take necessary measures to reroute or stop trains in the vicinity of the repair work.

Displaying stop signals is a vital safety protocol. It visually informs train crews that they must stop before the switch, eliminating any ambiguity regarding the status of the track. This clear communication is important to maintain a safe operating environment during the repair process, thereby protecting both the maintenance crew and train operations.

The other options do not adequately address the safety and communication needs during switch repairs. Keeping all signals green could lead to confusion and possible safety hazards, as trains might continue moving towards a switch that is under repair. Resuming normal operations without clear restrictions would jeopardize safety, and confining repairs to nighttime hours may not be practical or necessary for all situations, particularly if immediate repairs are needed.