What is the critical rule during a breakdown recovery?

The critical rule during a breakdown recovery focuses on maintaining an equal or greater number of good cars to ensure the train can continue operations. This principle is vital because it enables the train to maintain its operational capability and safely transport passengers even in the event of a breakdown. Having enough functional cars allows for proper weight distribution and stability during transit, minimizing the risk of further complications or accidents.

While the other options highlight important aspects of safety and operational protocol, they do not directly address the immediate requirement for successful breakdown recovery. Checking all cars for mechanical issues, conducting complete inspections before moving, and accounting for passengers are crucial for overall safety and management but are secondary to the immediate necessity of ensuring that the train can still operate effectively with the resources available. In a situation where rapid recovery is required, having a sufficient number of functioning cars is paramount to executing a safe and timely resolution.