Cameron County press. [volume] (Emporium, Cameron County, Pa.) 1866-1922, 1909-11-18

iiiIj ing, but the instant he
Egl iii finds the arm stretching
out over the track, he
must come to a stop,
knowing that that block is occupied
by another train.
The energy mentioned above is cleo
tric!ty; the current being obtained
from a battery near each post. The
rails Of each block are made as if all
of one piece by connecting the joints
with wire. The extreme ends are then
connected and thus circl is formed
in which the current flows. When no
train is in the block, the mechanism
operated by the current pulls the arm
down and holds it there. When a
train enters the block the wheels and
aXles, combined with the rails, form
shorter circuit, the energy that held
the arm down is withdrawn and up it
swings to horizontal position.
Each block is independent of all
other blocks. When the last wheels
of train leave it, the current re-
sumes its flow and the signal arm
at the entrance is pulled down to the
proceed" position. But before the
hind wheels have finished doing this,
the front wheels of the locomotive
have entered the next block and
caused the arm there to rise to the
stop"
For single track line the auto
matte arrangement is the same, but
there is a signal at each end of the
block. TO prevent two trains on
single track line entering block at
the same time from opposite ends, be-
fore the entrance to a single track
block is reached the train sets a stop
signal at the far end of that block,
and as 1t enters it sets the entrance
signal 10 stop just as is done on
double track Half mile or more
before reaching the entrance signal of
each block the engineer comes to
what is called the distant" which
tells him how the other or "home"
signal is set.
AS the automatic signal is con-
structed it cannot show 'go ahead"
unless the entire combination of rails,
wire, current, magnet, etc, is work
ing perfectly. If wire parts, rail
breaks battery
: : :: !: !: E: :: :! !: :: =.
fails, a switch point
opens the slightest, NR
t h combination kS
fails and the re ~
leased arm re &4-KN
sumes the hori- "
zontal position. SO, Hh
when the engineer I'm
sees the stop sig y
nal, he knows that III ~
there may be \
train on the block,
an open switch, or
a broken rail or n
signaling appa ii
ratus.
At night colored lights are display
ed on the same posts. The lamps
will burn eight days without replen-
ishing, but are refilled every four or
five days. When the home signal is
at stop, the engineer sees the flame
through a red glass. The caution light
on the distant is yellow. green
lights means go ahead and is used
on both the home and distant signals.
Where two or more lines cross at
grade the general plan of semaphore
arms for day and colored light for
night is the same, but owing to the
complications all signals are con.
trolled by levers operated by men
from central station. The crossing
and contiguous tracks are governed
by the interlocking system. When
this is in perfect order and the cross
ing unoccupied, it displays stop" to
every track approaching the crossing.
Any change must be made by the sig
mailman, and to display proceed" he
must first lock all other approaches
with the stop signal.
There are now about II 900 miles
of railway equipped with the block
system. The only line thus protected
every inch from Chicago to California
is via the Northwestern, Union and
Southern Pacific. One-third of the
1000 miles of automatic signaling is
on the Hartman lines-and the North
western has more miles of double
track automatic than any other rail.
way.