The morning news. [volume] (Savannah, Ga.) 1887-1900, 1895-01-06

pressure IN the pipe and setting the
brakes. When The handle Is moved 90
set the brakes the pert through which the
air enters the train pipe from the main
reservoir is closed. so that no ar Is re-
leased from this tank while the brakes
are being set A governor on the pump
shuts off the steam and thus stops the
pumD when the maximum air pressure
has been accumulated IN the train pipe
and reservoirs. About severity pounds or
air are kept IN the auxiliary reservoirs
for experience has shown that a higher
pressure sets the brakes so hard ihat
the wheels slide The air in The main res
ervoir Is kept at about ninety pounds
pressure. SO that the engineer always
has an excess of pressure at his COM
mand
The triple valve Is the controlling mech
anisru of the system after the air gets
past the engineer. II is called the triple
valve because through il the auxiliary
reservoir is charged from the train pipe;
the brake cylinder is charged from the
auxiliary reservoir and, in an emergency
stop, from the train pipe. and the air Is
released from the brake cylinder after the
brakes are set ami the train is ready to
move on. These triple functions are Sc
cured 10y an arrangement OF valves within
the casing Of the triple valve. When the
engineer opens the port In his valve,
which permits the air from the main
reservoir to escape into the train pipe. he
holds it open until the pressure gauge
before him tells him that the train pipe
has seventy pounds of air. The air passes
from the train pipe into the triple valve
and through q small opening on the rim
OF the seat Of large valve into the aux
Hilary reservoir Until the auxiliary res
ervoir is fully charged the pressure on this
large seated valve is greater ON the side
" 10 he in rtfp " q 10 r.
voir is fully charged the pressure IS the
same and the valve is balanced. In this
condition there is no pressure in the brake
cylinder. and, in fact, by means Of port
or opening in the triple valve, the brake
cylinder IS open to tine outside air. When
the engineer approaches a station he
moves the handle Of his valve TO a Ger
tain position and allows some of the air
in the train pipe to escape. The instant
this is done the pressure in the train pipe
is lowered. and the broad-seated valve
in the triple valve Is pushed out by the
compressed air in the auxiliary reservoir.
As this valve moves back, il first closes
the port which connects the brake cyin-
der with the outside air and let's the air
from the tank under the car enter the
brake cylinder The opening is small, but
compressed air IS elastic, and the air
rushes through this opening and forces
the piston in the brake cylinder forward.
The piston in turn pushes the piston rod
out Of the cylinder, and this rod, con-
nected with the brake levers, sets the
brakes.
The experienced engineer can handle
his valve so that the pressure is gradually
applied. When he wishes TO release the
brakes he opens the port which allows
air 10 pass from the main reservoir to the
train pipe. and as the pressure IN the pipe
is now greater than the pressure IN the car
tanks the broad-seated valve is moved
forward again. closing the port between
the reservoir and the brake cylinder and
at the same time opening the port be-
tween the brake cylinder and the outside
air The compressed air IN the cylinder
thus escapes. and as the pressure f. re-
duced cooled spring So the brake cyln-
der reacts and shoves the piston back to
its original position, thus releasing the
brakes.
When the engineer sees danger ahead
and knows that he must bring every
brake shoe on the train against the
wheels in the shortest possible time and
as hard as air can move them he throws
the handle of his valve to the emergency
stop, This opens the large port. and the
air in the train pipe is suddenly released
in large volumes and this as suddenly
lowers the pressure. Then the stored
pressure in the reservoirs under the cars