What must be done with a defective switch until it has been inspected and repaired?

The requirement to remove a defective switch from service immediately emphasizes the critical nature of safety in railway operations. A defective switch poses significant risks to both the trains and crew, as it can lead to operational failures or accidents. By taking this immediate action, it ensures that the switch is not used in its compromised state, potentially preventing incidents that could arise from malfunctioning equipment.

Furthermore, this protocol aligns with safety regulations that prioritize the integrity of railway infrastructure. Inspections and repairs are crucial steps that need to be carried out before any further use. This approach helps maintain overall safety standards and operational reliability on the railway system, ensuring that all components function correctly and reducing the risk of accidents.

In this context, other options suggest varying degrees of continued use despite the defect, which could jeopardize safety and lead to even more severe consequences. Hence, the immediate removal from service is the only appropriate action to uphold safety protocols.