In what position must the drum switches be at both operating ends of a PA5 train ready for passenger service?

The correct response is the "Isolate position." This position is necessary to ensure that the train systems are disabled and safe for maintenance or inspection before entering passenger service. When the drum switches are in the isolate position, it prevents any unintended activation of traction or other systems that could pose a risk during operations.

This is crucial for the safety of both passengers and crew. If the switches were in an active position, it could lead to accidental movements or operations of the train systems. Being in a neutral position may not provide the necessary safety measures; while it might disengage some functions, it does not guarantee the full isolation needed before allowing passengers onboard. The emergency position is designed for use during specific emergency situations and is not appropriate for standard passenger service readiness.