White Bluffs spokesman. [volume] (White Bluffs, Wash.) 1907-1938, 1926-09-17

been attained by the Great Northern,
according to official announcement of
the completion by that road of an
automatic block signal system extend
ing from st. Paul to Seattle, a dis
lance of 1,794 miles. This is said. to
be the longest unbroken signal install
lation on single railway anywhere
in the world. On this route train
leaving st. Paul for Seattle operates
under the block system every foot of
the journey, there being no gaps or
breaks whatever in the continuity of
the signaling system. Other main
line mileage provided with the auto
matte block system brings the total
up to 2,9SS.5 miles SO equipped on the
Great Northern lines.
This work was started in small
way during 1905, at which time the
three position upper-quadrant sema-
phore signal was adopted as standard.
In 1907, 100 miles of track was pro-
vided with automatics in Northern
Minnesota, and In 1908 block signal
ing and interlocking for all main line
switches on the four track railroad
were installed from st. Paul to Min
neapolis. During the succeeding
years this work progressed gradually
until the close of the year 1922. Be-
ginning with the year 1928 the devel-
opment in the science of optics made
hn NJ hn funf
signal possible. The outstanding adj
vantages of this new type Of signal
over the old style semaphore war
ranted it's adoption as standard on the
Great Northern. This signal affords
great simplicity and reliability Of in
dication, there being no rotary or NOV
ing parts subject to arrangement in
operation or to freezing in the
clear" positions.
At night time railway signals of
necessity are displayed by lights and
1t Is consistent to use the same colors
by day, now that 1t is feasible to do
So This produces uniformity of sig
nails for the guidance of enginemen
and trainmen throughout the "a hours
of the day. The colored light signal
has the further advantage over the
semaphore of greater average VISIBLE
ity. This is particularly important
during the hours Of darkness, also
during the twilight zone preceding
sunrise and following sunset, or in
the presence of smoke, or In foggy
weather. The colored light signal has
excellent penetrability and when most
needed Is at its best, contributing
much to the safety of train operation.
For clearance reasons the semaphore
signal Is mounted on a high mast
while the colored light signal is
mounted on a low mast which brings
1t into more direct line of the vision of
the man in the engine cab.
One of the interesting features of
the colored light system In use on the
Great Northern is the remarkable re-
suits which have obtained with lamps
which are even smaller than those
commonly used in an automobile
headlight. The skillful use of lenses
with Swat lamp has produced a
signal with beam of light brilliant
enough to be seen by the engineer
for more than a mile in bright day
light, and at night, of course, this
beam of light could be seen much fur
Their.
Another interesting feature Is the
manner In which the supply of current
OF constant voltage Is furnished to
these signals in territory where gen
orally there Is no commercial power
available. A considerable part of the
Great Northern Is constructed through
the mountains, and in such districts
where no outside supply of power Is
ated by means of primary chemical
batteries which are constantly charg
Ing set OF storage batteries, which
In turn furnish current of constant
voltage and volume to the signals.
1t is of special interest to note that
there is not a single oil lamp In use
In these signals the entire distance
from st. Paul to Seattle, electric
lamps being used throughout
The entire signal system Is 80 in
stalled that If anything should go
wrong with any part of the apparatus
the result would be a red signal dis
played, to an approaching train.
Great Northern officials claim their
road has gone farther in the installa-
ton of colored light signals than any
other road in the country. and the
locomotive engineers have been espe-
cially pleased with the results OBJ
tanned, inasmuch as the system Is at
Its best when 1t Is needed most; that
is, at night, in the rain or In smoke
or fog.
In the 1874 miles OF signaling be-