What must a train operator do after stopping at a red automatic signal with a "K" sign?

After stopping at a red automatic signal with a "K" sign, the train operator must pull up to the signal and stop, then release the automatic stop arm. This procedure is critical because it ensures that the train is stopping correctly in accordance with track signals and safety protocols.

The "K" sign indicates that there are specific actions that need to be taken after stopping at the red signal. This stop allows the operator to assess the situation and react appropriately to any potential hazards or instructions. By stopping first, the operator ensures the safety of the train and its passengers, maintaining a controlled environment before proceeding.

Releasing the automatic stop arm is also necessary, as it typically signals the system that the train is ready to continue, provided conditions are safe. This is a standard operation to prevent false signals that could lead to confusion on the track or with other train operations.

Choosing to proceed without stopping, using a manual override, or waiting for further instructions may not comply with local regulations or safety guidelines. These alternatives could compromise safety or lead to violations of operating procedures. Thus, following the established protocol of stopping, assessing, and then releasing the stop arm is the correct course of action for a train operator.