Where does the regulating valve derive its input pressure from?

Where does the regulating valve derive its input pressure from?

• A. Brake pipe
• B. Main reservoir
• C. The atmosphere
• D. Air intake

Answer: (B)

The regulating valve draws its input pressure from the main reservoir. In a train braking system, the main reservoir stores high-pressure air that is kept there by the compressor. The regulator then steps that high pressure down to the lower, controlled pressure used in the brake pipe and cylinders. The atmosphere isn’t used to feed the regulator, and the brake pipe is the output being controlled, not the source feeding the regulator. So the input to the regulating valve is the pressure from the main reservoir.

The regulating valve draws its input pressure from the main reservoir. In a train braking system, the main reservoir stores high-pressure air that is kept there by the compressor. The regulator then steps that high pressure down to the lower, controlled pressure used in the brake pipe and cylinders. The atmosphere isn’t used to feed the regulator, and the brake pipe is the output being controlled, not the source feeding the regulator. So the input to the regulating valve is the pressure from the main reservoir.