Evening journal., 1907-04-01
SIGNALS THAT
CAN BE SEEN
New 5, stem On Pennsylvania
Railroad Branch For Test
ing Eneinemen
is SIMPLE AND EFFICIENT

- SANA LL nltB II lOlLlN ! ]
For use in the magnificent new unionl
terminal in Washington. an improved
system Of signaling trains has been de-
vised. In order to be perfectly sure that
its operation will be satisfactory in every
respect a trial installation has just been
completed on a branch line of the Penn
sylvania railroad, running southwest from
Philadelphia to Media.
For some years It has been apparent
that signalling methods We're growing
over-complex. Engineers sometimes conn
planned that when running at 7O-mile or
more gait il was difficult to read with.
absolute accuracy the signs displayed on
post oftentimes containing as many As
fve semaphore arms Therefore tho de-
signers Of this particular system set out
TO reduce the subject to the simplest terms
and remove every possible opportunity for
mistake.
The particular feature Of this SYSTEM
accordingly, is its simplicity. All the nee
essary Instructions - TO running his train
are given to the engineer by two scma-
phore arms in the daytime, or two lights
az night upon each signal post In most
present systems the number Of arms or
lights on any one post varies according 70
location and the surrounding track arr
rangement Some posts may have two sig
mails and others az many as five.
Tho former systems We're gradually built
up to meet the conditions. and as the track
arrangements became more complicated
arms and lights were added, but the
system as a whole was not reconstructed
70 take care OF modern conditions. The
new system is the result oi several years
study. covering an examination OF the
best signals in use in this country and in
Europe. The signals may be operated
either automatically by the train or by
men in signal towers.
| II is surprising that with only two arms
and two lights on each post all the infor-
nation necessary 10 properly run tho train
can be given. Each arm may be independ-
emily placed in three positions. when it
stands out horizontally it means "ston
and the same meaning Is conveyed when
the lamp shows "a red light al night when
the arm Is raised until it stands upright Il
means clear track ahead" and the light
at night is white; when the arm is raised
I half way up il means caution" and the
Hight is green.
The upper signal arm on each pole gov
erns trains running az high speed. and the
second arm governs train movements At
medium speed
The system is based ON the principle OF
speed signalling. instead Of route signal.
ling. In route signalling it Is customary
20 have a separate arm for each possible
route. and Il Is Therefore necessary for th,
engineer 20 remember exactly what eaci
arm on each particular signal pole means
This is an extremely difficult thing TO do
for the number OF arms on dinerent post
by the route system varies according q
the particular track arrangement and
each engineer has 20 have constantly Il
mind complete map OF an the surround
ing tracks and switches
4 With the new system n the engineer
running a high speed train and the upnc
signal shows clear" he goes along with
out paying further attention to che signals
realizing that the track is prepared fo
him. II however. the top signal is put Il
the stop" position and the medium spec,
or second signal is put in the clear" posi-
tion, he realizes that the movement wh.cl
his train is TO carry out must not be don,
at high speed but can be properly car
ried out al say 30 miles an hour. He can a
once conform to the signals. and inter
prets them with certainty
Tho arrangement OF the particular
switches indicates to him which moderate
! speed route ne is 70 take. and th's is reail,
a matter of secondary Importance. for j.
his speed is properly lowered he is pre-
pared for any Of the moderate spec,
routes.
Slow train movements upon side track
and other low speed routes are govsrne,
by small signal arms and low powe
lights, placed tolerubly close to the groun,
so that they in no way interfere with tn
two-arm two-light principle embodied p
this new system. There are. Of course
many places where the track arrangcmen
Is such shat 20 medium route exists. Fo
instance, between stations there will b
many miles Of track without switches o
II erossovers Of any kind and movement OF
this track would be safe at any speed, an
Is consequently governed by the higl
; speed signal.
: In such locations as these. the sigma
arm for the moderate speed route IS sta
tionary. and is fixed in the stop position
The light also burns red at night. Their
are other locations IN which II is impossi
be 10 run at high speed under any condi
tion. and where all trains must take IN
moderate speed signal. In these location
the high speed signals are fixed in tn
horizontal position. indicating stop" an
the light burns red.
The engineer always expects to see tw
signal arms or two lights and he alway
finds them, so that the Interpretation O
the meaning Of The signals ON any on
pole is exactly the same as the interpreta
tion Of their meaning on any other pole
1t H. this uniformity which is Of such grea
assistance in securing accuracy in the in
structions conveyed to the engineer.
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