What is the correct pressure in the brake pipe when fully released for PA4 cars?

The correct pressure in the brake pipe when fully released for PA4 cars is 110 psi. This specification is critical as it ensures safe and efficient operation of the train’s braking system. When the brake pipe pressure is at 110 psi, it indicates that the system is correctly set to allow for proper functioning of the air brakes. This operating pressure ensures that the brakes can release effectively, allowing for smooth acceleration and deceleration as needed.

Understanding the acceptable pressure range is important for train engineers as it affects overall train safety and performance. If the brake pipe pressure is significantly lower or higher than this specified value, it may lead to improper brake function, risking the safety of the train and its passengers.