On a Push-button Control Panel, an Auxiliary Switch operating key is used to move and lock a switch when?

The correct choice is that an Auxiliary Switch operating key is used to move and lock a switch without setting up a route. This reflects a fundamental aspect of railway signaling and control systems, where it is crucial to ensure that switches can be manipulated manually under certain circumstances for safety or operational efficiency.

In scenarios where no route has been established, the use of an Auxiliary Switch operating key allows an operator to intervene directly with the switch mechanism. This is important during maintenance operations, emergency situations, or when addressing signal malfunctions, ensuring that the infrastructure remains functional and safe.

Additionally, this capability is essential because moving switches only after a route is established or when signals are clear typically relies on automated systems that prevent conflicts and ensure safe passage. However, operators must retain the ability to manage infrastructure flexibly, especially when automated systems are not engaged.