Evening star. [volume] (Washington, D.C.) 1854-1972, 1906-10-06

poles to the far end of the section behind
simultaneously fixes the fish-tailed dis
tant' signal there.
The joints Of the rails carrying these
currents are filled with wires insuring
good electrical conductor. At the ends of
each block section where the current crosses
through the coil to the returning rail there
Is an insulation preventing the electricity
from passing on to the rails Of the adjoining
section.
To avoid the expense and complication Of
a separate home and distant" signal
at every post, what is known as the three
position automatic signal has been de-
vised. In this there is for each track but
one semaphore arm, which when hori-
zontai means STOP" vertical. go ahead.
full speed" and at an angle of forty-ave
degrees, stop at next signal" This
makes 1t combined home and distant sig
nal, for when there Is a train in the sec
ond but not the first section ahead it
stands at the angle mentioned, thus giving
the same warning as the lower Of the pair
of semaphores above described when the
latter Is horizontal.
Thus we have seen so far how trains Sig
nal each other without the interference Of
man. With this automatic system one
man can attend to the switching and sig
mailing Of a large railway terminal and can
thus do the work of the five or more need
ed in one tower to throw the heavy levers
of the manual system. He has standing
vertically before him perfect working
model of the complicated system Of tracks
system is equipped with little rails and
switches which automatically turn when
ever he turns the corresponding real
switches down in the yard and by con-
slant reference to this mechanical toy he
always knows where he is at The cur
rents darling in all directions from the
electric buttons or switches at his fingers
ends control the switches and signals by
embarrassing various kinds of motive pow
er-some electro-ma gnetic, some electro
pneumatic, some 'all air. and others ALI
electric" depending upon the system adopt
ed The accompanying photographs show
the automatic system as installed by the
Union Switchboard and Signal Company,
which has equipped the heavy traffic lines
of the Pennsylvania and other great rail-
roads.
Interlocking Systems.
With both the manual and automatic
systems "interlocking'' safety devices are
now generally used. The moving of a
number of manual levers or electric
switches in wrong sequence may at any
time result in collision. But at crossings
interesting lines are by this invention
now "interlocked'' against each other. the
apparatus refusing to give clear" signals
to both tracks at the same time, just as at
draw bridges signals are interlocked with
the apparatus locking the draw. At such
danger points diverging track Is provided,
often to carry the train out OF danger IN
case the engineman disobeys the stop
signal
Railway Experts Opinion.
This whole problem of railway control was
clearly summed up for the writer the other
day by Mr.. Clifford Stanley Sims. former
general manager of the Baltimore and Ohio
railroad, and now railway expert whose
professional advice is being sought by the
officials of the great roads Of the country.
1.-The old train order system is still used