What must be visually determined during a Class III Brake Test if there is no operative EOTD on the rear of the train?

During a Class III Brake Test, if there is no operative End of Train Device (EOTD) on the rear of the train, it is necessary to visually confirm that the brakes apply and then release on the rear car. This step is crucial because it ensures that the entire train's braking system is functioning properly and that the rear car can effectively stop when needed.

Checking the application and release of brakes on the rear car is a safety measure to confirm that the braking system engages and disengages correctly throughout the train. If the brakes do not apply or fail to release, this could result in unsafe conditions while the train is in motion. Therefore, this visual determination is a critical aspect of the Class III Brake Test, ensuring compliance with safety regulations and operational standards.

The other options do not encompass the necessary actions required during this specific scenario. For example, merely confirming that brakes release only would not provide adequate assurance of the braking system's functionality, nor would stating that brakes do not apply address the need for testing the rear car effectively. Lastly, dismissing the need for action doesn’t align with safety protocols that mandate thorough inspection and testing of all components.