Eagle River review. [volume] (Eagle River, Wis.) 1890-1927, 1909-11-19

lNIOI rs it universally used?'
mo. There's only one
NH IlA line from Chicago to New
AIR HIN York thus protected, and
IIO iii of the total in the United
III HIN States one-tilird is on the
uI I|1 Union and Southern Pa
kW~uU cific.
Take three blocks at the beginning
of line with train in each. Train
in first must not move to second until
the train in second goes to third, and
train in second must not go into third
until third moves to fourth.
LAS number three goes into fourth, IT
tells train in two it has done so. and
train in two going into block three makes
the movable arm say to train in one.
Come on. I've gone into block two.
"As an illustration, let's take three
connecting rooms at your home, com
municating without doors Now attach
on the right hand-going from the front
to the back-of each door frame a NOV
able stick which can be pushed to right
angles with the door frame, or pointed
down about as you would point your arm
at a spot on the floor two feet from you
Got that? Your stick represents the
'semaphore, arm Now, then, the
middle room is your private office. Your
servant knows by the arm being at right
angles she must not enter. and when
you are not in there the stick will point
downward at so degrees and she may
usher a visitor in.
Gail very simple you say; but on a
busy morning you rush in your office
and forget to change the arm to denote
occupied The servant ushers in the last
person in the world you want there, just
then-and the scheme is a disastrous
failure Then you improve so the stick
left to itself will remain firmly at right
angles. Can't forget that, you figure
Next thing you do is to forget to change
the position of the stick. The employe
sees signal occupied and turns away an
important client with disaster almost
equal to that caused by admitting the
one she shouldn't.
"You change things so the stick will
move from right angle to pointing to
the floor, when you are not in your
office. You can in walking from the
front room into your Office release the
ARM which will go to horizontal; it will
stay in that position as long as you are
in there; and when you walk out of
your office into the back room it will be
pulled down to indicate you have vacat-
ed; and your employe may take the next
caller in.
Gin other words, you have changed this
device from a possible human forgetful-
ness to positive mechanical perform
ance; you have an automatic signal.
Substitute the consecutive lengths of
a railway for your rooms, and you have
the block signal"
''Then, as l understand it, a sema-
phore arm located at the entrance to
block set at right angle to the post is
signal to an approaching train to stop
and when pointing diagonally toward the
ground means keep Oh SO4HS Les
you call it automatic?'
"1t is. Just as your stick is kept at
90 degrees incline, when your office is
vacant. SO is the semaphore arm on the
line when a block is unoccupied. When
a train enters a block it affects the en-
ergy which is part of automatic sig
Mailing, SO that the arm goes to and re-
mains horizontal as long as the block is
occupied.
"You build these signals so their nor
NAL position is stop and then you apply
force that makes them show keep
going. Why is that?"
because the trains must keep going
They have not only the problems of
safety but of hurry up. They work by
minutes and seconds. The first duty
is safety. Having that cinched, the au-
tomato hangs out the signal to keep
moving. Only when, something occu's
does this scheme cause signal to go to
stop position
What's the energy you referred tor
from?' Battery near each post" How
is it worked?" ''The rails of each block
are made just as if all one piece, by
connecting all joints with wire. Then
complete circuit. The current flows in
this circuit. Machinery made out of ex-
perience, wheels, springs and things is
moved by this current; and it's move
ments either hold the arm down or per-
nit it to stay horizontal:
with no train in block, the current
makes the mechanism pull the arm down
and hold it there. When train enters
block it destroys this combination. The
wheels and aXles combined with the rails
make a shorter circuit. Electric current
deserts the longer for the shorter way
round. The energy that held the arm
down is withdrawn, and up it swings to
horizontal
each block is independent of all other
blocks. When the last wheels of train
leave it, the current resumes it's flow,
and the SIGNAL hack ar the
entrance is pulled down to proceed. Be
fore the hind wheels have ceased doing
what I've just stated. the front wheels
of the locomotive have entered the next
block and repeated what it did in the
previous blocks"