How does the parking brake valve typically work in relation to air pressure, in terms of push or pull control?

Pick an answer

1. Pulling the control out releases the parking brakes rather than applying them, the opposite of how it actually works
2. The control has no relationship to air pressure at all
3. Pushing the control in releases the parking brakes (using air pressure to hold springs back), and pulling it out applies them
4. Pulling the control out always releases the parking brakes

Correct!

Not quite. The correct answer is highlighted.