The diamond drill. (Crystal Falls, Iron County, Mich.) 1887-1996, 1891-10-24

tertes and controlled by signal lever
Of the pneumatic machine. When air
ID admitted 70 the cylinder the piston
rod Is forced up aud the semaphore
blade Is lowered When the air Is ex-
hausted the counterpoise on the soma
phore brings II TO danger again.
ALTHOUGH the operating mechan-
isnis OF the switch and signal are sepa-
rate, the switch and its signal are far
from being independent Of each other.
Iiy Ingenious automatic devices. me.
chanical and electrical II Is made inn
possible for the operator TO know
clear signal until after switch Is
moved and securely locked In the
proper position. and each signal when
cleared automatically locks the lever
operating IL and prevents its being
used TO release conflicting signals or
switches until IL has been ngain placed
completely ut danger. These auto
matte devices are called the interlocls-
ing mechanism.
''Ovcr the pneumatic machine. in
closed In glass ease. is miniature
model OF the switching yard showing
every track, switch. frog and every
movable frog between Taylor street
and the station. Whenever switch Is
moved the model switch moves too, SO
that the operator can tell at glance
the position of affairs in the yard under
his charge"
After the old-timer had satisfied his
mechanical curiosity 10y examining
every switch IN the yard. the party
swarmed aboard switch engine and
rolled on 10 the main track toward
Robey street TO look into the electric
pneumatic block signaling system.
Electrician Ray called attention 10
high post on the right side of the track
having two large scmaphore blades,
the upper one red, the lower green.
This is block signal and the move
ment of the semaphores Is controlled
entirely and automatically 10y the en-
CINE, car or hand car passing over the
rails. A block is the section OF track
between two such signals. the lengths
of blocks varying according To circum-
stances ana eXigencies The sema-
phores are thrown TO safety or clear
that Is, the blades then point down at
an angle OF 60 degrees, by compressed
air. Unlike the semaphores on switch
signals, block semaphores stand nor
mally at clear. Now, little electro
magnate operates the valve which adj
mits or exhausts the compressed air
into the cylinder of the mechanism
which moves the semaphores.
A. current of electricity Is passed
around n piece of soft iron. giving the
property OF magnetism 90 the iron only
so long as the current is on. Now, the
steel rails OF the track within n block
are the conductors which carry the
electric current, generated by common
gravity batteries. through the electro
magnet, which operates the com
pressed air valve Of the signal mechan-
ism. The rails are connected with
each other at the splice bars by wire,
and, ms the rails of each block are en-
tirely insulated from those adjoining.
each block has its own circuit,
As the current is always on, the arma.
ture OF the magnet operating the valve
nolds il open, and the air pressure
keeps the semaphore blades at
safety" But suppose the electric
-urrent is suddenly switched off the
electro magnet IL loses its magnetism.
the armature no longer attracted 20 II
is drawn back by n spring the valve
turns, shutting off the air pressure and
the heavy counter weights on the
semaphore causes II 20 rise 10 horizon
tai position, and SO indicates danger.