buting valve when making an
independent application of the brake.

A. When the independent brake valve handle is moved to application
position, air is admitted from the reducing valve pipe through the
application cylinder pipe to the application chamber and cylinder.
Pressure forming in the application cylinder will move the application
piston 10 to the right, carrying with it the exhaust valve 16 and the
application valve 5, closing the exhaust port and opening the supply
port, admitting main reservoir air from chamber "a" to the brake
cylinders (see Fig. 12) until the pressure in the brake cylinders and
chamber "b" slightly exceeds that in chamber "g", when the application
piston 10 and valve 5 will move back to lap position. By moving the
brake valve handle to either release or running position, the air is
exhausted from the application cylinder and chamber, thus reducing the
pressure in chamber "g", allowing the pressure in chamber "b" to force
the piston to the left, carrying with it the exhaust valve 16, opening
the exhaust ports "e" and "d", allowing the air from the brake cylinders
to escape to the atmosphere, thus releasing the brake.

DISTRIBUTING VALVE DEFECTS

140. Q. If the locomotive brake released with the automatic brake valve
in lap position, where would you look for the trouble?

A. Would look for a leak in the application cylinder pipe or in the
application cylinder cap gasket.

141. Q. If the brake remained applied in lap position, but released in
release or holding position, where would you look for the trouble?

A. Would look for a leak in the distributing valve release pipe.

142. Q. If the distributing valve release pipe and application cylinder
pipe were crossed, what would be the effect?

A. A brake application made by the automatic brake valve cannot be
released by the independent brake valve.

143. Q. If the safety valve leaks, what will be the effect?

A. This may prevent the brake applying, and in an independent
application if the brake does apply, it will release when the brake
valve is returned to lap position.

BROKEN PIPES

144. Q. If the main reservoir supply pipe to the distributing valve
breaks, what should be done?

A. Plug the pipe toward the main reservoir. The locomotive brake is
lost, but if the distributing valve is equipped with a quick action cap,
when an emergency application is made, the air coming from the brake
pipe, through the quick actio