What must be done if it is necessary to cut out the air brakes on the rear car?

Setting the car out at the first available location is the correct procedure when it becomes necessary to cut out the air brakes on the rear car. This is crucial for ensuring safety and maintaining the train’s operational integrity. If the brakes on the rear car are cut out, it may pose a risk for that car to become unstable or difficult to control.

By setting the car out at the first available location, you can take it off the train, reducing the risk of potential accidents related to the inoperative brakes. This action also allows the remainder of the train to operate safely without the complications introduced by a car with non-functioning brakes.

Other options may not address safety adequately: leaving the car in place could create hazards during movement, moving the car forward might exacerbate the situation with ineffective braking, and cutting out the brakes and continuing could lead to uncontrolled movement issues. Therefore, setting the car out is the most prudent choice for maintaining safety and train integrity.