If blocks are applied to a switch that cannot be locked, what additional action is required?

When blocks are applied to a switch that cannot be locked, it is critical to ensure its safety and proper functioning. By ensuring the switch is lined and spiked or wedged, you are taking the necessary steps to secure the switch in a fixed position, which minimizes the risk of unintended movement. This action provides physical security to the switch, maintaining its alignment and ensuring that it does not accidentally change position, which could lead to dangerous situations on the track.

This precaution is essential in situations where locking is not possible, as it compensates for the lack of a locking mechanism by physically restraining the switch in its desired position. When a switch is effectively lined and spiked or wedged, it mitigates any potential hazards that could arise from a misaligned switch or unexpected train movements.

In contrast, removing the switch or notifying only the engineer fails to address the immediate safety needs of the scenario. Conducting a full system check, while important in broader contexts, does not provide the immediate corrective action required for securing a non-lockable switch.