What must an employee do after cutting out air brakes on a car?

After cutting out the air brakes on a car, the most appropriate action for the employee is to notify the train operator. This is crucial because the air brakes are an essential safety feature that ensures the train can stop effectively. By informing the train operator, you ensure that they are aware of the changed status of the car and can take any necessary precautions or make informed decisions regarding the operation of the train. This communication is vital for maintaining safety protocols and operational integrity on the rail system.

The other actions—cutting out traction motors, documenting the action, and inspecting the car's wheels—are not the primary step required after air brakes have been cut out. While documentation may be necessary for recordkeeping and safety audits, it follows the immediate need to inform the train operator. Similarly, inspecting the wheels may be part of a routine procedure but is not specifically mandated as an immediate response to cutting out air brakes.