The Appeal. [volume] (Saint Paul, Minn. ;) 1889-19??, 1909-06-26

RI kxZI3z%X1Ea printed from the
SS$A lSME Popular Science
Monthly. I'm con-
| sidering," he be-
| TES= gins, whether
| = some of our fire.
Quent railroad accidents may not be
due to the character of the signals we
employ, it should be borne in mind
that these signals must be caught and
instantly translated into action under
conditions of uncommon mental stress
And for this reason defects of the SYM
bols which might otherwise be far
from serious do NOT become of vital
moment"
| Prof. Stratton goes on to tell about
the severity of locomotive engineers
work. He says:
He must know that his outside
lights are burning bright, that the wa
ter in the boiler is sufficient, that the
alr-brakes are in perfect working. He
must from moment to moment glance
at the hands of his watch, and must
know exactly where he is upon the
road. And yet all the while his eyes
must hardly be taken from the dark
ness into which his engine rushes, to
catch the first glimmer of the signal
| which is his guide.
Since the safety of many lives
thus depends upon these signal lights
and upon their sudden clearness to a
mind that must attend to many things
at once, the symbols should at all
times be the least ambiguous that can
DO planned. Yet the present night sig
nails, given by colored lights beside
| the track-upon many roads, white for
Safety red for danger and green for
proceed with caution-are open to
grave objections.
For the human eye at it's best and
without abnormality is liable to mis-
take the signal hues at night, especial
~ when the outward conditions are
anyw1se untoward, whether by the dis
lance or the low burning of the lamp
| Or by fog or smoke Or storm. And
even when the colors are perceived
with perfect accuracy the use of the
common oil light called 'white,' as one
OF the signal colors, throws a danger
GUS task upon the engineer, inasmuch
as it requires him to take constant
heed lest he regard some window
lamp or other meaningless light along
his course as a sign that all is we'll
and in consequence rush onward to his
trains destruction.
In regard to the use of white as
part of the signal code at night the
danger from this source has long been
recognized by leading signal engineers.
although in spite of this recognition
It's use continues on large number Of
our American roads. 1t is not many
years ago that an accident occurred
at Whittenton Junction, Mass. from
this very cause. The, engineer mis-
took lantern hanging from the gate
at street crossing for his safety sig
nal and crashed into another train.
More recently Mr.. Baggett of the Gal
weston, Harrisburg & San Antonio
road has given an instance where dis
| aster resulted from the use of white.
The railway signal in this case was
| SAOSIAy III AAAO Will d 4lSuL SQll1n2
from'a high bay window; and when
the signal light itself was out one
night the engineer mistook the light in
| the window for his signal and seri-
GUS accident was the outcome.
'sThe disadvantage under which the
red danger signal labors is, however.
quite insufdciently expressed by say
ing that the ruby glass often virtually
destroys fully four-fifths of the light
from lantern flame already none too
bright, and to this extent increases
the liability that the most momentous
| of the signals will at some crisis be
seen too late or not at all. Even the
| remaining portion is often far less ef-
fectual upon the eye than it's physical
quality would lead us to expect. The
Importance Of the matter for signaling
| will perhaps Justify some further &C.
| count.
IF, by reliable devices of the labora.
tory. semaphore light showing
white be gradually reduced in bright
ness, point can easily be found
| where the eye, grown accustomed to
the dark, can just perceive the light.
| And when, for comparison, a railroad
ruby glass, or ROUNDED II placed be-
fore the lamp, the observer now OBJ
tains no conscious impression at all.
But, instead Of having to increase five
fold the brightness coming through
the glass Gas one might expect, know
ing that the red glass is pervious. say.
to but one-fifth of the light of the
dame), it is necessary to increase it
no less than fourteen-fold.
'Such an increase is the least I have
found necessary when experimenting
at night over a stretch of more than
1000 feet, and when smoke gave a rel
alive advantage to the red. Within
the laboratory the red has never been
perceptible until the light was in
creased Is times the brightness re-
Quired for white. Such, however. are
the most favorable experiments, and
are by no means average ones. On the
average, 1t is necessary to increase
the light as much as 30 times before
any conscious impression at all is
made by the light through the red
glass"