What occurs when an emergency alarm box in the subway is activated?

When an emergency alarm box in the subway is activated, it triggers a comprehensive safety protocol designed to protect both passengers and personnel. This includes the critical action of removing power from the third rail, which is essential for preventing electric shock or accidents. Additionally, an alarm will sound to alert the appropriate authorities and other passengers that there is an emergency situation in the area.

This dual response ensures that immediate action is taken to address the emergency while maintaining safety in the train system. The combination of these actions enhances the overall safety measures in place, differentiating this response from scenarios where only one action might occur. Therefore, the correct response accounts for both the activation of alarms and the disconnection of power, highlighting the seriousness of the situation and the need for rapid intervention.