release position of the brake valve, air from the main reservoir
flows direct to the brake pipe, causing a rise of pressure which is felt
in chamber "p" on the right or brake pipe side of the equalizing piston
26; this increase of pressure will cause the piston to move toward the
left, carrying the graduating valve 28 and slide valve 31 to release
position.

[Illustration: Fig. 10. Service Lap.]

This allows the air from the application chamber and cylinder to flow to
the distributing valve release pipe "IV" and on through the independent
brake valve to the automatic brake valve, where the port to which this
pipe leads is blanked by the automatic rotary valve, thus preventing the
air from leaving the application chamber and cylinder, holding the
locomotive brake applied while the train brakes are being released. The
movement of the parts, and the results obtained are the same where the
release is made in holding position.

133. Q. Explain the movement of the parts in the distributing valve when
the brake valve is moved to running position after having first been
moved to release or holding position, following a brake application.

A. In this position of the brake valve the port to which the
distributing valve release pipe is connected is open to the exhaust,
thus allowing the air to escape from the application chamber and
cylinder. The reduction of pressure in chamber "g", will allow the brake
cylinder pressure in chamber "b" to force the application piston and its
valves to release position, thus allowing the brake cylinder air to
escape to the atmosphere, through the exhaust ports "e" and "d". (See
Fig. 8.)

134. Q. Explain how an independent release of the locomotive brake is
obtained after an automatic application has been made.

A. If the brakes have been applied throughout the train, by means of the
automatic brake valve, and it is desired to release the locomotive
brakes without releasing the train brakes, the handle of the independent
brake valve is placed in release position. In this position of the
independent brake valve, the application cylinder in the distributing
valve is connected through the application cylinder pipe to the direct
exhaust port of the independent brake valve; thus exhausting the air
from the application cylinder, causing a release of the locomotive
brake. This independent release of the locomotive brake does not cause
the equalizing piston and its slide valve in the distributing va