When should an operator use the route request button at interlocking home signals?

Using the route request button at interlocking home signals is crucial for maintaining efficient train operations and safety protocols. The correct context for using this button is when the signal indicates stop. When a signal displays a stop indication, it typically means the route is not yet clear, and the operator must confirm their route before proceeding.

In this scenario, activating the route request button allows the operator to signal their intention to proceed while ensuring that the signaling system processes their request for the route to be cleared. This proactive step is vital for avoiding potential conflicts with other trains, ensuring that the interlocking system can safely manage traffic based on real-time conditions.

If the signal indicates clear, there is no need to use the route request button as the operator can proceed directly. Preparing for departure or approaching a station may require other actions related to train control and communication, but they do not specifically involve the use of the route request button in the context of an interlocking home signal.