The Manitowoc pilot. [volume] (Manitowoc, Wis.) 1859-1932, 1909-11-18

rake three blocks at the beginning
OF a line with train in each. Train
IN nrst 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.
AS number three goes into fourth. 1t
tells train in two II has done so, and
traln 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
municating without doors. Now attach
on the right hand-gong from the front
to the back-of each door frame 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 spot on the floor two feet from you
Got that? Your stick represents the
semaphore, or arm Now, them the
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 60 degrees and she may
usher a visitor in.
"All very simple you say but on
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 cmplOye
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 win
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 1t will
N no ng
in there; and when you walk out of
your office into the back room 1t will be
pulled down to indicate you have vacat-
ed and your employe may take the next
caller in.
an other words, you have changed this
device from a possible human forgetful-
ness to a positive mechanical perform
ance: you have an automatic signal.
Substitute the consecutive lengths of
railway for your rooms. and you have
the block signal"
Then, as l understand It. a sema-
phore arm located at the entrance TO a
block set at right angle to the post is a
signal to an approaching train to stop,
and when pointing diagOnally toward the
ground means keep on going?' Yes"
you call 1t 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 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
a 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 occurs
does this scheme cause signal to go to
stop position
whats the energy you referred tor
Electric current" where does It come
from? Battery near each post" How
is ii worked?' THE rails Of each block
are made just as If all one piece by
connecting all joints with wire. Then
connecting the extreme ends forms "a
complete circuit. The current flows in
this circuit. Machinery made out of eN-
moved by this current; and its 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 a train enters
a block it destroys this combination The
wheels and axles combined with the rails
make 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 a train
leave 1t, the current resumes it's flow,
ana the signal arm away back at 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 ii did in the
previous blocks"