What action should be taken if a switch cannot be locked in place?

The appropriate action when a switch cannot be locked in place is to set it to the required position with blocks applied. This ensures that the switch remains in the correct position for safe train operation, preventing unintended movement that could lead to accidents. Applying blocks provides a physical barrier that holds the switch securely in place even if it cannot be locked mechanically, helping maintain operational safety until the issue can be resolved completely.

It's important to prioritize safety and ensure that the switch functions as intended whenever it is in use; thus, merely notifying the train crew or leaving the switch unlocked would not adequately mitigate potential risks. Similarly, removing the switch from service may not be necessary if it can be safely managed in the interim with block application, allowing for continued operations with caution.