What is the overall purpose of the automatic brake valve?

What is the overall purpose of the automatic brake valve?

• A. To lower or raise the brake pipe pressure, thus applying and releasing the train air brakes
• B. To increase reservoir pressure
• C. To seal lines
• D. To monitor speed

Answer: (A)

The automatic brake valve controls the train’s braking by changing the brake pipe pressure. When it is set to apply, it lowers the brake pipe pressure, which causes each car’s triple valve to release air from the brake cylinders and apply the brakes. When it’s set to release, brake pipe pressure is restored and the brakes release. This is how braking is enacted along the entire train, either for an automatic service brake or a full release, based on the pressure in the brake pipe. It doesn’t directly boost reservoir pressure, seal lines, or monitor speed.

The automatic brake valve controls the train’s braking by changing the brake pipe pressure. When it is set to apply, it lowers the brake pipe pressure, which causes each car’s triple valve to release air from the brake cylinders and apply the brakes. When it’s set to release, brake pipe pressure is restored and the brakes release. This is how braking is enacted along the entire train, either for an automatic service brake or a full release, based on the pressure in the brake pipe. It doesn’t directly boost reservoir pressure, seal lines, or monitor speed.