The herald., 1893-09-19
ELECTRIC TRACTION.
THE HYDRAULIC PRINCIPLE APPLIED
TO ELECTRICITY.

How the Trolley Works--A Continuous
Current That May Be Tapped at Any
Point. Like Water Main. Supplies the
Motive Power For Thousands OF Cars.
"Within very few years" said Presi-
dent Lewis Of the Brooklyn City Rail-
road company, "horse cars viii bethings
Of the past. All the big cities have
adopted or are experimenting with cable
or electric cars, and there is no hkeli-
hood Of a return to the old system. The
popular prejudice against the trolley is
dying out, and as its cleanliness and su-
perior accommodation and facilities are
appreciated there will be an irresistible
demand for its introduction. There was
a great outcry against 1t at first, princi-
pally because Of the universal ignorance
Of electricity and dread OF its applica-
ton. Now that it has been practically
demonstrated that travel on the trolley
car is, no more dangerous than in the
horse car people are beginning to forget
that'they know absolutely nothing of the
power by which they are carried nor Of
the manner in which that force is ap-
Piled"
"Those are just the points The Eagle
desires to explain to its readers"
II cannot explain them. am satis-
fed to accept the general result and to
leave the intricacies of the system to the
electricians and engineers"
The reporter found M. j. Starrett, the
chief electrician Of the Brooklyn City
Railway company, in his Office and pro-
pounded to him the questions that had
foored President Lewis.
''The points are difficult to explain, i"
said Mr.. Starrett. ''because of their SIM
plicity yet comprehensibility. But l
will try what can do. You must keep
In your minds eye picture of the
tracks on which the car travels and the
single wire above, which is connected
with the car by the trolley pole Then
You must remember that under certain
pressure electricity will flow through q
wire the same as water will fowthrough
a pipe. Electricity is generatedsby ma
chinery at the power stations Of the car
companies and stored as water is stored
in the reservoirs and is conducted through
the wires by pressure as the water is
conducted through the mains. The cleo
tricity forced through the wires is never
expended as long as the pressure is kept
up at the power station. It is drawn
upon and does its work, returning to the
power station through the rails and re-
turn wires laid under the tracks.
"In the same manner the water of an or
namental fountain spurts through tubes
and falls to its reservoir to be spurted
up and fall again ad infnitum. The big
wires running alongside the car tracks
are reservoirs Of electricity-feeders, as
it were, to the single trolley wire. These
are carefully insulated except at the
points Of contact with the conducting
feeders. The small wire could not con-
tain the amount of electricity needed any
more than a two inch pipe could carry
more than two inches of water. That
current of electricity is the propelling
force Of the trolley cars
"Above each car is pole. At the up
per end of the pole is metal wheel. The
pole itself is made of hollow steel, be-
cause steel, good conductor, is lighter
and has more spring than any other ma
terial yet discovered. Wood, with a
wire run through the center, would serve
the same purpose, but would not be as
cheap or as durable. The base of the
trolley pole is Joined to suitable wiring
that, concealed in the woodwork of the
car, connects beneath the car with the
controlling devices that operate the
wheels. There are four Of these devices,
and others are being invented and expert
mented with frequently.
1.-TWO of these devices are for cutting
off the current, and the others are for
braking the wheels. The conductor of
the car can also shut off the current by
disconnecting the trolley pole from the
overhead wire. With the devices under
the car in operating order the current
reaches the motor. There, under the
manipulation of the motorman, it does
its work in causing shaft geared to the
axles to revolve. The motor applying
the pressure force to the electricity that
reaches it from the overhead wire acts
as a counterpart Of the generator at the
power station. The power there for the
first time becomes mechanical and not
electrical. The majority Of the motors
are of 25 horsepower each, and there are
two to each car"
sis there no danger of any accident
from the uninsulated wire?" asked the
reporter.
"None whatever. An accident is, to
all intents and purposes, impossible. A
sparrow resting on the wire would nei-
therinterrupt the current nor suffer from
the contact. A man might climb to the
wire and swing on it, and unless his feet
touched the rails or rested on a piece of
iron he would not feel the slightest
shock. If he stood on ladder with
wooden rungs, it would be the same. If
the wheels of car were lifted from the
tracks, the circuit would be cut and the
trolley pole could not draw electricity
from the wire. If car should run off
the track only an inch, it would stop for
want Of propelling power. Stones are
not conductors. and stones are laid be-
tween and outside all electric car tracks.
The comparatively few accidents that
have occurred since the development Of
the system are in no way to be attribut-
ed to electricity"
When the trolley system is fully devel-
oped on the 200 miles Of streets controlled
by the Brooklyn City company, electrical
power will be supplied from three sta
tions, each station independent of the