The train engineer or operator can normally use a lever or handle to operate the SA-9 Independent Brake Valve. The operator can control the braking force and ensure a smooth train stop or deceleration by adjusting the air pressure provided to the brakes through the lever.
The valve controls how much compressed air travels from the air reservoirs in the railway to the brake cylinders on each vehicle. The valve opens and permits the air pressure to flow from the reservoirs to the brake cylinders, applying the brakes and slowing the train. This happens when the operator moves the lever or handle to the "brake on" position. The brakes are removed and the train is free to move when the lever is shifted to the "brake off" position, when the valve closes and the air pressure is released.
Because it offers accurate and independent control over the braking power, the SA-9 Independent Brake Valve is a crucial part of train braking systems. In order to operate trains safely and effectively, it enables the modification of braking force based on the weight, speed, and other variables.