Final answer:
In addition to an emergency alarm box, a train operator will find an automated external defibrillator (AED) at a blue light location in the subway, providing essential instructions and assistance for cardiac emergencies.
Step-by-step explanation:
Besides finding an emergency alarm box at a blue light location in the subway, a train operator would also always find an automated external defibrillator (AED). These portable units are crucial for providing assistance in the event of a cardiac emergency. Placed in many public places, AEDs offer verbal instructions to facilitate usage by bystanders, even those without medical training, during the critical first minutes following a cardiac attack.