Which of the following is NOT a position on the Brake Valve handle on PA4 cars?

The position that is considered NOT a valid option on the Brake Valve handle for PA4 cars is partial charge. The brake valve handle typically includes positions such as Full Release, Snow Brake, and Emergency, which are essential for regulating the braking systems in various situations during train operations.

Full Release allows the brakes to be released completely, enabling the train to move freely. The Snow Brake position is specifically designed to provide enhanced braking performance in snowy conditions, preventing wheel slip. The Emergency position is used for situations requiring immediate and maximum braking force, like a sudden stop to prevent an accident.

In contrast, a Partial Charge position is not standard terminology or functionality associated with the Brake Valve handle in PA4 cars. It does not reflect a common or defined state for braking action on this specific type of train. Understanding these distinct positions and their purposes is crucial for effective train operation and safety in various scenarios.